Lung cancer pathophysiology: Difference between revisions
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==Overview== | ==Overview== | ||
The [[pathophysiology]] of lung cancer includes both [[genetic]] and [[Environmental factor|environmental factors]]. [[Causality]] of majority of lung cancer is linked to [[Tobacco|tobacco usage.]] [[Carcinogen|Carcinogenic]] effects of [[tobacco smoking]] may result in [[DNA]] | The [[pathophysiology]] of lung cancer includes both [[genetic]] and [[Environmental factor|environmental factors]]. [[Causality]] of the majority of lung cancer is linked to [[Tobacco|tobacco usage.]] [[Carcinogen|Carcinogenic]] effects of [[tobacco smoking]] may result in [[DNA]] mis-replication and [[mutation]]. [[Smoking]] starts a [[cascade]] of events that leads to [[cancer]] development, even decades after [[smoking cessation]]. Besides [[Smoking|smokers]], [[Patient|patients]] with the history of prior [[Respiratory tract neoplasm|respiratory tract]] or [[gastrointestinal tract cancer]] comprise a high-risk population. Other [[Environmental factor|environmental factors]] include [[radon]], [[asbestos]], [[viral infections]], and states of [[Pulmonary inflammation|chronic lung inflammation]], all of which may [[Predisposition|predispose]] to [[cellular]] damage and [[DNA mutations]] that [[Predisposition|predispose]] to the development of lung cancers. | ||
==Pathophysiology== | ==Pathophysiology== | ||
The [[pathophysiology]] of lung cancer includes both [[genetic]] and [[Environmental factor|environmental factors]].<ref name="KanwalDing2017">{{cite journal|last1=Kanwal|first1=Madiha|last2=Ding|first2=Xiao-Ji|last3=Cao|first3=Yi|title=Familial risk for lung cancer|journal=Oncology Letters|volume=13|issue=2|year=2017|pages=535–542|issn=1792-1074|doi=10.3892/ol.2016.5518}}</ref><ref name="KadaraScheet2016">{{cite journal|last1=Kadara|first1=H.|last2=Scheet|first2=P.|last3=Wistuba|first3=I. I.|last4=Spira|first4=A. E.|title=Early Events in the Molecular Pathogenesis of Lung Cancer|journal=Cancer Prevention Research|volume=9|issue=7|year=2016|pages=518–527|issn=1940-6207|doi=10.1158/1940-6207.CAPR-15-0400}}</ref><ref name="RasoWistuba2007">{{cite journal|last1=Raso|first1=Maria Gabriela|last2=Wistuba|first2=Ignacio I.|title=Molecular Pathogenesis of Early-Stage Non-small Cell Lung Cancer and a Proposal for Tissue Banking to Facilitate Identification of New Biomarkers|journal=Journal of Thoracic Oncology|volume=2|issue=7|year=2007|pages=S128–S135|issn=15560864|doi=10.1097/JTO.0b013e318074fe42}}</ref> | The [[pathophysiology]] of lung cancer includes both [[genetic]] and [[Environmental factor|environmental factors]].<ref name="KanwalDing2017">{{cite journal|last1=Kanwal|first1=Madiha|last2=Ding|first2=Xiao-Ji|last3=Cao|first3=Yi|title=Familial risk for lung cancer|journal=Oncology Letters|volume=13|issue=2|year=2017|pages=535–542|issn=1792-1074|doi=10.3892/ol.2016.5518}}</ref><ref name="KadaraScheet2016">{{cite journal|last1=Kadara|first1=H.|last2=Scheet|first2=P.|last3=Wistuba|first3=I. I.|last4=Spira|first4=A. E.|title=Early Events in the Molecular Pathogenesis of Lung Cancer|journal=Cancer Prevention Research|volume=9|issue=7|year=2016|pages=518–527|issn=1940-6207|doi=10.1158/1940-6207.CAPR-15-0400}}</ref><ref name="RasoWistuba2007">{{cite journal|last1=Raso|first1=Maria Gabriela|last2=Wistuba|first2=Ignacio I.|title=Molecular Pathogenesis of Early-Stage Non-small Cell Lung Cancer and a Proposal for Tissue Banking to Facilitate Identification of New Biomarkers|journal=Journal of Thoracic Oncology|volume=2|issue=7|year=2007|pages=S128–S135|issn=15560864|doi=10.1097/JTO.0b013e318074fe42}}</ref> | ||
* Lung cancer | * Lung cancer consists of several [[Histologically|histological types]]. | ||
* Main [[Histological|histological types]] of lung cancer include: | * Main [[Histological|histological types]] of lung cancer include: | ||
** [[Small cell lung cancer]] | ** [[Small cell lung cancer]] | ||
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*** [[Large cell carcinoma of the lung]] | *** [[Large cell carcinoma of the lung]] | ||
*** [[Sarcomatoid carcinoma of the lung]] | *** [[Sarcomatoid carcinoma of the lung]] | ||
* [[Smoking]] starts a cascade of events that leads to [[cancer]]. | * [[Smoking]] starts a [[cascade]] of events that leads to [[cancer]]. | ||
=== | === Lung Cancer Pathogenesis === | ||
* [[ | * Lung cancer [[pathogenesis]] can be understood with the help of the following [[hypothesis]]: | ||
* | |||
* [[ | ===== '''Familial lung cancer''' ===== | ||
** [[ | |||
** | **[[Chromosome 6 (human)|6q23–25]] [[Locus (genetics)|locus]] has been identified as a [[Susceptible individual|susceptibility]] [[gene]] for familial lung cancer. | ||
** | ===== '''Multistep tumorigenesis''' ===== | ||
** | |||
**[[Tumor|Tumors]] of [[Organ (anatomy)|organs]] such as [[Skin cancer|skin]], [[lung]] and [[Colorectal cancer|colon]] are developed through a process called [[Tumorigenesis|multistep tumorigenesis]]. | |||
** As with other [[Epithelium|epithelial]] [[Cancer|malignancies]], lung cancers are believed to arise from [[Precancerous|preneoplastic]] or precursor [[lesions]] in the [[Respiratory system|respiratory]] [[mucosa]]. | |||
**[[Tumorigenesis|Multistep tumorigenesis]] is the development of [[tumor]] through a series of progressive [[Pathological|pathologic]] events such as [[Precancerous|preneoplastic]] or [[Precursor|precursor lesions]] with corresponding [[genetic]] and [[Epigenetic|epigenetic aberrations]]. | |||
**[[Hyperplasia]], [[squamous metaplasia]], [[Dysplasia|squamous dysplasia]], and [[Carcinoma in situ|carcinoma ''in situ'' (CIS)]] comprise changes in the [[Bronchus|large airways]] that precede or accompany [[squamous cell carcinoma of the lung|invasive squamous cell carcinoma of the lung]].<ref name="pmid18039118">{{cite journal |vauthors=Wistuba II, Gazdar AF |title=Lung cancer preneoplasia |journal=Annu Rev Pathol |volume=1 |issue= |pages=331–48 |date=2006 |pmid=18039118 |doi=10.1146/annurev.pathol.1.110304.100103 |url=}}</ref> | |||
** Multistep [[tumorigenesis]] explains [[pathogenesis]] of centrally located [[squamous cell carcinoma of the lung]] very well but fails to explain the [[pathogenesis]] of [[Large cell carcinoma of the lung|large cell lung carcinomas]], [[Adenocarcinoma of the lung|lung adenocarcinomas]], and [[small cell lung cancer]]. | |||
===== '''Accumulation of Molecular Abnormalities''' ===== | |||
** Another [[theory]] on the [[pathogenesis]] of lung cancer is the accumulation of [[Molecule|molecular]] abnormalities beyond a certain threshold point, rather than the sequence of alterations. | |||
* | ** There are no known [[Precancerous|preneoplastic lesions]] for the most common type of [[Carcinoid syndrome|neuroendocrine lung tumors]], [[Small cell lung cancer|small cell carcinoma of the lung]], | ||
**[[Adenocarcinoma of the lung pathophysiology|Atypical adenomatous hyperplasia (AAH)]] is the only sequence of [[Morphology (biology)|morphologic]] change identified leading to the development of [[Adenocarcinoma of the lung|invasive adenocarcinoma of the lung.]] | |||
*[[Pathogenesis]] of lung cancer is thought to be result of both due to stepwise, sequence-specific and multistage [[Molecular pathology|molecular pathogenesis]] and due to accumulation and combination of [[Genetics|genetic]] and [[Epigenetics|epigenetic]] abnormalities. | |||
=== Field of Injury and Field Cancerization === | |||
* | *[[Premalignant condition|Preneoplastic lung lesions]] frequently extend throughout the [[respiratory epithelium]], indicating a field effect in which much of the [[respiratory epithelium]] has been [[Mutagen|mutagenized]], presumably from exposure to [[tobacco]]-related [[Carcinogen|carcinogens]].<ref name="DevarakondaMorgensztern2015">{{cite journal|last1=Devarakonda|first1=Siddhartha|last2=Morgensztern|first2=Daniel|last3=Govindan|first3=Ramaswamy|title=Genomic alterations in lung adenocarcinoma|journal=The Lancet Oncology|volume=16|issue=7|year=2015|pages=e342–e351|issn=14702045|doi=10.1016/S1470-2045(15)00077-7}}</ref><ref name="pmid27006378">{{cite journal |vauthors=Kadara H, Scheet P, Wistuba II, Spira AE |title=Early Events in the Molecular Pathogenesis of Lung Cancer |journal=Cancer Prev Res (Phila) |volume=9 |issue=7 |pages=518–27 |date=July 2016 |pmid=27006378 |doi=10.1158/1940-6207.CAPR-15-0400 |url=}}</ref><ref name="AuerbachStout1961">{{cite journal|last1=Auerbach|first1=Oscar|last2=Stout|first2=A. P.|last3=Hammond|first3=E. Cuyler|last4=Garfinkel|first4=Lawrence|title=Changes in Bronchial Epithelium in Relation to Cigarette Smoking and in Relation to Lung Cancer|journal=New England Journal of Medicine|volume=265|issue=6|year=1961|pages=253–267|issn=0028-4793|doi=10.1056/NEJM196108102650601}}</ref> | ||
** | *[[Epithelium|Epithelial cells]] lining the entire [[respiratory tract]] that have been exposed to [[smoking]] show [[Molecular pathology|molecular alterations]] that may signify the onset of lung cancer, a [[paradigm]] known as the "airway field of injury”. | ||
** | * | ||
** [[ | *[[Premalignant]] [[airway]] fields in the [[molecular]] [[pathogenesis]] of lung cancer: | ||
**[[Smoking]] induces widespread [[Molecular pathology|molecular alterations]], such as [[gene expression]] changes in exposed [[Epithelium|epithelia]] throughout the [[Respiratory tract|respiratory tract.]] | |||
** The [[airway]] field of [[injury]] can be seen in [[Smoking|smokers]] with or without lung cancer and is highly relevant for the identification of [[Tumor marker|markers]] for [[Minimally invasive adenocarcinoma of the lung|minimally invasive]] and early detection of lung cancer. | |||
** The adjacent [[airway]] field of [[Oncogenesis|carcinoma]] represents the field in normal appearing [[Airway|airways]] adjacent to [[lung]] [[Tumor|tumors]]. | |||
** It has been suggested that in this adjacent field of [[tumor]], there is closer [[Molecular pathology|molecular genealogy]] between lung cancers and [[Airway|airways]] that are in closest proximity to the [[Tumor|tumors]] compared to [[Airway|airways]] that are more distant from the [[tumors]]. | |||
** The progression of the [[molecular]] [[airway]] field of [[injury]] to [[Precancerous|preneoplasia]] and [[lung]] [[malignancy]] is still not clear. | |||
**[[Molecular pathology|Molecular changes]] involved in the development of the [[airway]] field of [[injury]] and changes mediating progression of this field to [[lung]] [[Precancerous|preneoplasia]] may help the identification of early [[Marker|markers]] for lung cancer detection and [[Chemoprophylaxis|chemoprevention]]. | |||
==Genetics== | ==Genetics== | ||
*Lung cancer is initiated by activation of [[oncogene]]s or inactivation of [[tumor suppressor gene]]s.<ref name="Fong">{{cite journal | last =Fong | first =KM | coauthors = Sekido Y, Gazdar AF, Minna JD | title =Lung cancer. 9: Molecular biology of lung cancer: clinical implications | journal =Thorax | volume =58 | issue =10 | pages =892–900 | publisher = BMJ Publishing Group Ltd. | date =Oct 2003 | pmid =14514947 }}</ref> | *Lung cancer development is initiated by the activation of [[oncogene]]s or inactivation of [[tumor suppressor gene]]s.<ref name="Fong">{{cite journal | last =Fong | first =KM | coauthors = Sekido Y, Gazdar AF, Minna JD | title =Lung cancer. 9: Molecular biology of lung cancer: clinical implications | journal =Thorax | volume =58 | issue =10 | pages =892–900 | publisher = BMJ Publishing Group Ltd. | date =Oct 2003 | pmid =14514947 }}</ref> | ||
*[[Mutation]]s in the ''[[Ras|K-ras]]'' [[proto-oncogene]] are responsible for 20% to 30% of non-small cell lung cancer cases.<ref name="Aviel-Ronen">{{cite journal | last =Aviel-Ronen | first =S | coauthors = Blackhall FH, Shepherd FA, Tsao MS | title =K-ras mutations in non-small-cell lung carcinoma: a review | journal =Clinical Lung Cancer | volume =8 | issue =1 | pages =30–38 |publisher =Cancer Information Group | date =Jul 2006 | pmid =16870043 }}</ref><ref name="pmid23122493">{{cite journal |vauthors=Karachaliou N, Mayo C, Costa C, Magrí I, Gimenez-Capitan A, Molina-Vila MA, Rosell R |title=KRAS mutations in lung cancer |journal=Clin Lung Cancer |volume=14 |issue=3 |pages=205–14 |year=2013 |pmid=23122493 |doi=10.1016/j.cllc.2012.09.007 |url=}}</ref> | *[[Mutation]]s in the ''[[Ras|K-ras]]'' [[proto-oncogene]] are responsible for 20% to 30% of non-small cell lung cancer cases.<ref name="Aviel-Ronen">{{cite journal | last =Aviel-Ronen | first =S | coauthors = Blackhall FH, Shepherd FA, Tsao MS | title =K-ras mutations in non-small-cell lung carcinoma: a review | journal =Clinical Lung Cancer | volume =8 | issue =1 | pages =30–38 |publisher =Cancer Information Group | date =Jul 2006 | pmid =16870043 }}</ref><ref name="pmid23122493">{{cite journal |vauthors=Karachaliou N, Mayo C, Costa C, Magrí I, Gimenez-Capitan A, Molina-Vila MA, Rosell R |title=KRAS mutations in lung cancer |journal=Clin Lung Cancer |volume=14 |issue=3 |pages=205–14 |year=2013 |pmid=23122493 |doi=10.1016/j.cllc.2012.09.007 |url=}}</ref> | ||
*[[Chromosome|Chromosomal]] damage may also result in [[loss of heterozygosity]], which subsequently leads to the inactivation of [[tumor suppressor genes]]. | *[[Chromosome|Chromosomal]] damage may also result in the [[loss of heterozygosity]], which subsequently leads to the inactivation of [[tumor suppressor genes]]. | ||
*Damage to the following [[chromosomes]] are particularly common in small cell lung carcinoma: | *Damage to the following [[chromosomes]] are particularly common in small cell lung carcinoma: | ||
**[[Chromosome 3|Chromosome 3p]] | **[[Chromosome 3|Chromosome 3p]] | ||
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*Several [[genetic polymorphism]]s are associated with lung cancer. These include [[polymorphisms]] in [[gene]]s coding for:<ref name="Engels">{{cite journal | last =Engels | first =EA | coauthors =Wu X, Gu J et al. | title =Systematic evaluation of genetic variants in the inflammation pathway and risk of lung cancer | journal =Cancer Research | volume =67 | issue =13 | pages =6520–6527 | publisher =American Association for Cancer Research | date =Jul 2007 | pmid =17596594 }}</ref><ref name="Wenzlaff">{{cite journal | last =Wenzlaff | first =AS | coauthors =Cote ML, Bock CH et al. | title =CYP1A1 and CYP1B1 polymorphisms and risk of lung cancer among never smokers: a population-based study | journal =Carcinogenesis | volume =26 |issue =12 | pages =2207–2212 | publisher =Oxford University Press | date =Dec 2005 | pmid =16051642 }}</ref><ref name="Son">{{cite journal | last =Son | first =JW | coauthors =Kang HK, Chae MH et al. | title =Polymorphisms in the caspase-8 gene and the risk of lung cancer | journal =Cancer Genetics and Cytogenetics | volume =169 | issue =2 | pages =121–127 | date =Sep 2006 | pmid =16938569 }}</ref><ref name="Yin">{{cite journal | last =Yin | first =J | coauthors =Vogel U, Ma Y et al. | title =The DNA repair gene XRCC1 and genetic susceptibility of lung cancer in a northeastern Chinese population | journal =Lung Cancer | volume =56 | issue =2 | pages =153–160 | date =May 2007 |pmid =17316890 }}</ref> | *Several [[genetic polymorphism]]s are associated with lung cancer. These include [[polymorphisms]] in [[gene]]s coding for:<ref name="Engels">{{cite journal | last =Engels | first =EA | coauthors =Wu X, Gu J et al. | title =Systematic evaluation of genetic variants in the inflammation pathway and risk of lung cancer | journal =Cancer Research | volume =67 | issue =13 | pages =6520–6527 | publisher =American Association for Cancer Research | date =Jul 2007 | pmid =17596594 }}</ref><ref name="Wenzlaff">{{cite journal | last =Wenzlaff | first =AS | coauthors =Cote ML, Bock CH et al. | title =CYP1A1 and CYP1B1 polymorphisms and risk of lung cancer among never smokers: a population-based study | journal =Carcinogenesis | volume =26 |issue =12 | pages =2207–2212 | publisher =Oxford University Press | date =Dec 2005 | pmid =16051642 }}</ref><ref name="Son">{{cite journal | last =Son | first =JW | coauthors =Kang HK, Chae MH et al. | title =Polymorphisms in the caspase-8 gene and the risk of lung cancer | journal =Cancer Genetics and Cytogenetics | volume =169 | issue =2 | pages =121–127 | date =Sep 2006 | pmid =16938569 }}</ref><ref name="Yin">{{cite journal | last =Yin | first =J | coauthors =Vogel U, Ma Y et al. | title =The DNA repair gene XRCC1 and genetic susceptibility of lung cancer in a northeastern Chinese population | journal =Lung Cancer | volume =56 | issue =2 | pages =153–160 | date =May 2007 |pmid =17316890 }}</ref> | ||
**[[Interleukin 1|Interleukin-1]] | **[[Interleukin 1|Interleukin-1]] | ||
**[[Cytochrome P450]] | **[[Cytochrome P450]] | ||
**[[ | **[[Caspase]]-8, an [[apoptosis]] promoter | ||
**[[XRCC1]], a [[DNA]] repair molecule | **[[XRCC1]], a [[DNA]] repair molecule | ||
*Individuals with these [[polymorphisms]] are thought to be more likely to develop lung cancer following exposure to [[Carcinogen|carcinogens]]. | *Individuals with these [[polymorphisms]] are thought to be more likely to develop lung cancer following exposure to [[Carcinogen|carcinogens]]. | ||
==Environment== | ==Environment== | ||
Although genetics play a significant role in the [[pathogenesis]] of lung cancer, it is thought that exposure to environmental risk factors plays an equally | Although genetics play a significant role in the [[pathogenesis]] of lung cancer, it is thought that exposure to environmental [[Risk factor|risk factors]] plays an equally important role in the development of lung cancer. The main causes of lung cancer include [[carcinogen]]s (such as those present in [[tobacco smoke]]), [[ionizing radiation]], and [[virus (biology)|viral]] infections. [[Chronic (medical)|Chronic]] exposure results in cumulative alterations to the [[DNA]] in the [[Tissue (biology)|tissue]] lining the [[bronchi]] of the [[Lung|lungs]] (the [[bronchial]] [[epithelium]]). Irreversible [[DNA]] changes following exposure to [[carcinogens]] are directly associated with the development of lung cancer.<ref name="pmid22054876">{{cite journal |vauthors=Dela Cruz CS, Tanoue LT, Matthay RA |title=Lung cancer: epidemiology, etiology, and prevention |journal=Clin. Chest Med. |volume=32 |issue=4 |pages=605–44 |year=2011 |pmid=22054876 |pmc=3864624 |doi=10.1016/j.ccm.2011.09.001 |url=}}</ref> | ||
===Smoking=== | ===Smoking=== | ||
*[[Cigarette]] smoking is a leading cause of lung cancer | *[[Cigarette]] [[smoking]] is a leading cause of lung cancer.<ref name="pmid10413421">{{cite journal |vauthors=Hecht SS |title=Tobacco smoke carcinogens and lung cancer |journal=J. Natl. Cancer Inst. |volume=91 |issue=14 |pages=1194–210 |year=1999 |pmid=10413421 |doi= |url=}}</ref><ref>Kluger, R. (1996). Ashes to ashes: America's hundred-year cigarette war, the public health, and the unabashed triumph of Philip Morris. New York: Alfred A. Knopf.</ref><ref>{{cite book | last = Proctor | first = Robert | title = The Nazi war on cancer | publisher = Princeton University Press | location = Princeton, N.J. Oxford | year = 2000 | isbn = 978-0691070513 }}</ref><ref name="Morabia2012">{{cite journal|last1=Morabia|first1=Alfredo|title=Quality, originality, and significance of the 1939 “Tobacco consumption and lung carcinoma” article by Mueller, including translation of a section of the paper|journal=Preventive Medicine|volume=55|issue=3|year=2012|pages=171–177|issn=00917435|doi=10.1016/j.ypmed.2012.05.008}}</ref><ref>Mueller F. Tabakmissbrauch und Lungencarcinom. Z. Krebsforsch. 1939;49:57–85.</ref><ref>Wynder, E. L. (1994). Prevention and cessation of tobacco use: Obstacles and challenges. J. Smoking-Related Dis. 5(Suppl. 1), 3–8.</ref><ref>Hanspeter Witschi ITEH and Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California 95616</ref><ref name="Hecht">{{cite journal | last =Hecht | first =S | title =Tobacco carcinogens, their biomarkers and tobacco-induced cancer | journal =Nature Reviews. Cancer | volume =3 | issue =10 | pages =733–744 | publisher =Nature Publishing Group | date =Oct 2003 | url =http://www.nature.com/nrc/journal/v3/n10/abs/nrc1190_fs.html;jsessionid=A78B217DFCAD36DD965F2DBA685CF121 | doi =10.1038/nrc1190 |pmid =14570033 | accessdate =2007-08-10 }}</ref><ref name="Nordquist">{{cite journal | last =Nordquist | first =LT | authorlink = | coauthors =Simon GR, Cantor A et al. | title =Improved survival in never-smokers vs current smokers with primary adenocarcinoma of the lung | journal =Chest | volume =126 | issue =2 | pages =347–351| publisher = American College of Chest Physicians | date =Aug 2004 | url =http://www.chestjournal.org/cgi/content/full/126/2/347 |pmid =15302716 | accessdate =2007-08-10 }}</ref><ref name="Peto">{{cite book | last = Peto R | first = R | coauthors = Lopez AD, Boreham J et al. | title = Mortality from smoking in developed countries 1950–2000: Indirect estimates from National Vital Statistics | publisher = Oxford University Press | date = 2006 | url=http://www.ctsu.ox.ac.uk/~tobacco/ | id = ISBN 0-19-262535-7 |accessdate =2007-08-10 }}</ref> | ||
*[[Cigarette]] | *[[Cigarette smoke]] contains over 60 known [[Carcinogen|carcinogens]] including [[radioisotopes]] from the [[radon]] decay sequence, [[nitrosamine]], and [[benzopyrene]]. | ||
*[[Nicotine]] is thought to reduce the [[immune response]] to [[malignant]] growths in exposed tissue. The length of time an individual smokes, as well as the amount, significantly increases the person's chance of developing lung cancer. | *[[Nicotine]] is thought to reduce the [[immune response]] to [[malignant]] growths in the exposed [[Tissue (biology)|tissue]]. The length of time an individual [[Smoking|smokes]], as well as the amount, significantly increases the person's chance of developing lung cancer. | ||
*Among individuals who stopped [[smoking]], the risk of lung cancer steadily decreases as [[lung]] [[Tissue (biology)|tissue]] repairs itself and as contaminant particles are eliminated from the [[lungs]]. | *Among individuals who stopped [[smoking]], the risk of lung cancer steadily decreases as [[lung]] [[Tissue (biology)|tissue]] repairs itself and as contaminant particles are eliminated from the [[lungs]]. | ||
*It is thought that the risk of lung cancer among persons with a history of [[smoking]] (even when stopped) is always higher than those who never [[Smoke|smoked]]. | |||
===Radon | ===Radon Gas=== | ||
The association of [[radon]] gas exposure to lung cancer is described below:<ref name="Catelinois">{{cite journal | last =Catelinois | first =O | coauthors = Rogel A, Laurier D et al. | title =Lung Cancer Attributable to Indoor Radon Exposure in France: Impact of the Risk Models and Uncertainty Analysis | journal =Environmental Health Perspectives | volume =114 |issue =9 | pages =1361–1366 | publisher =National Institute of Environmental Health Science | date =May 2006 | url =http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=16966089 | doi =10.1289/ehp.9070 | pmid =16966089 |accessdate =2007-08-10 }}</ref><ref name="radon">University of Minnesota.http://enhs.umn.edu/hazards/hazardssite/radon/radonmolaction.html#Anchor-Molecular-23240/</ref> | The association of [[radon]] [[gas]] exposure to lung cancer is described below:<ref name="Catelinois">{{cite journal | last =Catelinois | first =O | coauthors = Rogel A, Laurier D et al. | title =Lung Cancer Attributable to Indoor Radon Exposure in France: Impact of the Risk Models and Uncertainty Analysis | journal =Environmental Health Perspectives | volume =114 |issue =9 | pages =1361–1366 | publisher =National Institute of Environmental Health Science | date =May 2006 | url =http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=16966089 | doi =10.1289/ehp.9070 | pmid =16966089 |accessdate =2007-08-10 }}</ref><ref name="radon">University of Minnesota.http://enhs.umn.edu/hazards/hazardssite/radon/radonmolaction.html#Anchor-Molecular-23240/</ref> | ||
*[[Radon]] is a colorless and odorless [[gas]] generated by the breakdown of [[radioactive]] [[radium]] (decay product of [[uranium]]) found in the Earth's crust. The radiation decay products ionize [[genetic]] material, causing [[mutations]] that sometimes turn [[cancerous]]. | *[[Radon]] is a colorless and odorless [[gas]] generated by the breakdown of [[radioactive]] [[radium]] (decay product of [[uranium]]) found in the Earth's crust. The [[radiation]] decay products [[Ionization|ionize]] [[genetic]] material, causing [[mutations]] that sometimes turn [[cancerous]]. | ||
*[[Radon]] exposure is the second major cause of lung cancer following [[smoking]]. | *[[Radon]] exposure is the second major cause of lung cancer following [[smoking]]. | ||
*The mechanism of lung damage following radon exposure is not thought to be due to the [[radon]] gas itself, but due to the short-lived alpha decay products that cause cellular damage and [[DNA]] [[mutations]]. | *The [[Mechanism (biology)|mechanism]] of [[lung]] damage following [[radon]] exposure is not thought to be due to the [[radon]] [[gas]] itself, but due to the short-lived alpha decay products that cause [[Cell (biology)|cellular]] damage and [[DNA]] [[mutations]]. | ||
===Asbestos=== | ===Asbestos=== | ||
*[[Asbestos]] exposure is associated with many lung diseases, including lung cancer.<ref name="JärvholmÅström2014">{{cite journal|last1=Järvholm|first1=Bengt|last2=Åström|first2=Evelina|title=The Risk of Lung Cancer After Cessation of Asbestos Exposure in Construction Workers Using Pleural Malignant Mesothelioma as a Marker of Exposure|journal=Journal of Occupational and Environmental Medicine|volume=56|issue=12|year=2014|pages=1297–1301|issn=1076-2752|doi=10.1097/JOM.0000000000000258}}</ref> | *[[Asbestos]] exposure is associated with many [[lung diseases]], including lung cancer.<ref name="JärvholmÅström2014">{{cite journal|last1=Järvholm|first1=Bengt|last2=Åström|first2=Evelina|title=The Risk of Lung Cancer After Cessation of Asbestos Exposure in Construction Workers Using Pleural Malignant Mesothelioma as a Marker of Exposure|journal=Journal of Occupational and Environmental Medicine|volume=56|issue=12|year=2014|pages=1297–1301|issn=1076-2752|doi=10.1097/JOM.0000000000000258}}</ref> | ||
*Tiny [[asbestos]] fibers | *Tiny [[asbestos]] fibers released into the [[air]] are [[Breathing|breathed]] into the [[lungs]]. The fibers become lodged in the [[lungs]] and are stuck for an indefinite amount of time. They can eventually lead to [[Scar|scarring]] and [[inflammation]]. | ||
=== Viruses === | === Viruses === | ||
*[[Virus]]es | *[[Virus]]es known to be associated with the development of lung cancer in [[animals]] and [[Human|humans]] include:<ref name="Leroux">{{cite journal | last =Leroux | first =C | coauthors =Girard N, Cottin V et al. | title =Jaagsiekte Sheep Retrovirus (JSRV): from virus to lung cancer in sheep |journal =Veterinary Research |volume =38 | issue =2 | pages =211–228 | date =Mar-Apr 2007 | pmid =17257570 }}</ref><ref name="Palmarini">{{cite journal | last =Palmarini | first =M | coauthors =Fan H | title =Retrovirus-induced ovine pulmonary adenocarcinoma, an animal model for lung cancer| journal =Journal of the National Cancer Institute | volume =93 | issue =21 | pages =1603–1614 | publisher =Oxford University Press| date =November 2001 | url =http://jnci.oxfordjournals.org/cgi/content/full/93/21/1603 | pmid =11698564 | accessdate =2007-08-11}}</ref><ref name="Cheng">{{cite journal | last =Cheng | first =YW | coauthors = Chiou HL, Sheu GT et al. | title =The association of human papillomavirus 16/18 infection with lung cancer among nonsmoking Taiwanese women | journal =Cancer Research | volume =61 | issue =7| pages =2799–2803 | publisher = American Association for Cancer Research | date =Apr 2001 | url =http://cancerres.aacrjournals.org/cgi/content/full/61/7/2799 | pmid =11306446 | accessdate =2007-08-11 }}</ref><ref name="Zheng">{{cite journal | last =Zheng | first =H | coauthors =Aziz HA, Nakanishi Y et al. | title =Oncogenic role of JC virus in lung cancer | journal =Journal of Pathology | volume =212 | issue =3 | pages =306–315 | date =May 2007 | pmid =17534844 }}</ref><ref name="Giuliani">{{cite journal | last =Giuliani | first =L | coauthors =Jaxmar T, Casadio C et al. | title =Detection of oncogenic viruses (SV40, BKV, JCV, HCMV, HPV) and p53 codon 72 polymorphism in lung carcinoma | journal =Lung Cancer | volume=57 | issue=3 | pages=273–281 | date =Sep 2007 | pmid =17400331}}</ref><ref name="Engels 2">Eric A Engels.11/30/11. Inflammation in the development of lung cancer:epidemiological evidence.Expert Review of Anticancer Therapy.Apr.2008.p605</ref> | ||
**[[Human papillomavirus]] | **[[Human papillomavirus]] | ||
**[[JC virus]] | **[[JC virus]] | ||
**[[SV40|Simian virus 40 | **[[SV40|Simian virus 40 (SV40)]] | ||
**[[BK virus]] | **[[BK virus]] | ||
**[[Cytomegalovirus]] | **[[Cytomegalovirus]] | ||
**[[HIV]] | **[[HIV]] | ||
*These [[viruses]] may affect the [[cell cycle]] and inhibit [[apoptosis]], allowing uncontrolled [[cell division]]. | *These [[viruses]] may affect the [[cell cycle]] and [[Inhibition|inhibit]] [[apoptosis]], allowing uncontrolled [[cell division]]. | ||
*[[HIV]] has also been thought to increase the risk of developing lung cancer. Although the mechanism is unknown, [[HIV]] is thought to be associated with a state of chronic [[lung]] [[inflammation]] that may potentiate [[cellular]] damage and [[DNA mutations]]. | *[[HIV]] has also been thought to increase the risk of developing lung cancer. Although the [[Mechanism (biology)|mechanism]] is unknown, [[HIV]] is thought to be associated with a state of [[Chronic (medical)|chronic]] [[lung]] [[inflammation]] that may potentiate [[cellular]] damage and [[DNA mutations]]. | ||
===Infection and Inflammation=== | ===Infection and Inflammation=== | ||
*There may be a correlation between general [[inflammation]] of lung tissue and the development of lung | *There may be a correlation between general [[inflammation]] of [[lung]] [[Tissue (biology)|tissue]] and the development of lung cancer.<ref name="Engels 2" /> | ||
*[[Neutrophils]] are released in response to [[bacterial]] infection and are considered to be the initial responders during [[inflammation]]. | *[[Neutrophils]] are released in response to [[bacterial]] [[infection]] and are considered to be the initial responders during [[inflammation]]. | ||
*The hypothesis is that [[neutrophils]] may activate [[Reactive oxygen species|reactive oxygen]] or [[nitrogen]] species, which can bind to [[DNA]] and lead to [[genomic]] alterations. Accordingly, [[inflammation]] may be thought of as an initiator or [[promoter]] of lung cancer development. Also, tissue repair from [[inflammation]] is associated with [[cellular]] [[Cell growth|proliferation]]. During [[cellular]] [[proliferation]] there may be errors in [[chromosomal]] [[replication]] that can cause further [[DNA mutations|DNA mutation]]. | *The [[hypothesis]] is that [[neutrophils]] may activate [[Reactive oxygen species|reactive oxygen]] or [[nitrogen]] species, which can bind to [[DNA]] and lead to [[genomic]] alterations. Accordingly, [[inflammation]] may be thought of as an initiator or [[promoter]] of lung cancer development. Also, [[Tissue (biology)|tissue]] repair from [[inflammation]] is associated with [[cellular]] [[Cell growth|proliferation]]. During [[cellular]] [[proliferation]] there may be errors in [[chromosomal]] [[replication]] that can cause further [[DNA mutations|DNA mutation]]. | ||
*[[Angiogenesis]], a significant process during tumor growth, may be promoted by chronic states of [[inflammation]], which often require increased [[blood flow]] to sites of [[inflammation]]. | *[[Angiogenesis]], a significant process during [[tumor]] growth, may be promoted by [[Chronic (medical)|chronic]] states of [[inflammation]], which often require increased [[blood flow]] to sites of [[inflammation]]. | ||
==References== | ==References== |
Latest revision as of 20:22, 2 July 2019
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Kim-Son H. Nguyen M.D. Cafer Zorkun, M.D., Ph.D. [2] Dildar Hussain, MBBS [3] Michael Maddaleni, B.S.
Overview
The pathophysiology of lung cancer includes both genetic and environmental factors. Causality of the majority of lung cancer is linked to tobacco usage. Carcinogenic effects of tobacco smoking may result in DNA mis-replication and mutation. Smoking starts a cascade of events that leads to cancer development, even decades after smoking cessation. Besides smokers, patients with the history of prior respiratory tract or gastrointestinal tract cancer comprise a high-risk population. Other environmental factors include radon, asbestos, viral infections, and states of chronic lung inflammation, all of which may predispose to cellular damage and DNA mutations that predispose to the development of lung cancers.
Pathophysiology
The pathophysiology of lung cancer includes both genetic and environmental factors.[1][2][3]
- Lung cancer consists of several histological types.
- Main histological types of lung cancer include:
- Smoking starts a cascade of events that leads to cancer.
Lung Cancer Pathogenesis
- Lung cancer pathogenesis can be understood with the help of the following hypothesis:
Familial lung cancer
- 6q23–25 locus has been identified as a susceptibility gene for familial lung cancer.
Multistep tumorigenesis
- Tumors of organs such as skin, lung and colon are developed through a process called multistep tumorigenesis.
- As with other epithelial malignancies, lung cancers are believed to arise from preneoplastic or precursor lesions in the respiratory mucosa.
- Multistep tumorigenesis is the development of tumor through a series of progressive pathologic events such as preneoplastic or precursor lesions with corresponding genetic and epigenetic aberrations.
- Hyperplasia, squamous metaplasia, squamous dysplasia, and carcinoma in situ (CIS) comprise changes in the large airways that precede or accompany invasive squamous cell carcinoma of the lung.[4]
- Multistep tumorigenesis explains pathogenesis of centrally located squamous cell carcinoma of the lung very well but fails to explain the pathogenesis of large cell lung carcinomas, lung adenocarcinomas, and small cell lung cancer.
Accumulation of Molecular Abnormalities
- Another theory on the pathogenesis of lung cancer is the accumulation of molecular abnormalities beyond a certain threshold point, rather than the sequence of alterations.
- There are no known preneoplastic lesions for the most common type of neuroendocrine lung tumors, small cell carcinoma of the lung,
- Atypical adenomatous hyperplasia (AAH) is the only sequence of morphologic change identified leading to the development of invasive adenocarcinoma of the lung.
- Pathogenesis of lung cancer is thought to be result of both due to stepwise, sequence-specific and multistage molecular pathogenesis and due to accumulation and combination of genetic and epigenetic abnormalities.
Field of Injury and Field Cancerization
- Preneoplastic lung lesions frequently extend throughout the respiratory epithelium, indicating a field effect in which much of the respiratory epithelium has been mutagenized, presumably from exposure to tobacco-related carcinogens.[5][6][7]
- Epithelial cells lining the entire respiratory tract that have been exposed to smoking show molecular alterations that may signify the onset of lung cancer, a paradigm known as the "airway field of injury”.
- Premalignant airway fields in the molecular pathogenesis of lung cancer:
- Smoking induces widespread molecular alterations, such as gene expression changes in exposed epithelia throughout the respiratory tract.
- The airway field of injury can be seen in smokers with or without lung cancer and is highly relevant for the identification of markers for minimally invasive and early detection of lung cancer.
- The adjacent airway field of carcinoma represents the field in normal appearing airways adjacent to lung tumors.
- It has been suggested that in this adjacent field of tumor, there is closer molecular genealogy between lung cancers and airways that are in closest proximity to the tumors compared to airways that are more distant from the tumors.
- The progression of the molecular airway field of injury to preneoplasia and lung malignancy is still not clear.
- Molecular changes involved in the development of the airway field of injury and changes mediating progression of this field to lung preneoplasia may help the identification of early markers for lung cancer detection and chemoprevention.
Genetics
- Lung cancer development is initiated by the activation of oncogenes or inactivation of tumor suppressor genes.[8]
- Mutations in the K-ras proto-oncogene are responsible for 20% to 30% of non-small cell lung cancer cases.[9][10]
- Chromosomal damage may also result in the loss of heterozygosity, which subsequently leads to the inactivation of tumor suppressor genes.
- Damage to the following chromosomes are particularly common in small cell lung carcinoma:
- The TP53 tumor suppressor gene, located on chromosome 17p, is often mutated in lung cancers.[11]
- Several genetic polymorphisms are associated with lung cancer. These include polymorphisms in genes coding for:[12][13][14][15]
- Interleukin-1
- Cytochrome P450
- Caspase-8, an apoptosis promoter
- XRCC1, a DNA repair molecule
- Individuals with these polymorphisms are thought to be more likely to develop lung cancer following exposure to carcinogens.
Environment
Although genetics play a significant role in the pathogenesis of lung cancer, it is thought that exposure to environmental risk factors plays an equally important role in the development of lung cancer. The main causes of lung cancer include carcinogens (such as those present in tobacco smoke), ionizing radiation, and viral infections. Chronic exposure results in cumulative alterations to the DNA in the tissue lining the bronchi of the lungs (the bronchial epithelium). Irreversible DNA changes following exposure to carcinogens are directly associated with the development of lung cancer.[16]
Smoking
- Cigarette smoking is a leading cause of lung cancer.[17][18][19][20][21][22][23][24][25][26]
- Cigarette smoke contains over 60 known carcinogens including radioisotopes from the radon decay sequence, nitrosamine, and benzopyrene.
- Nicotine is thought to reduce the immune response to malignant growths in the exposed tissue. The length of time an individual smokes, as well as the amount, significantly increases the person's chance of developing lung cancer.
- Among individuals who stopped smoking, the risk of lung cancer steadily decreases as lung tissue repairs itself and as contaminant particles are eliminated from the lungs.
- It is thought that the risk of lung cancer among persons with a history of smoking (even when stopped) is always higher than those who never smoked.
Radon Gas
The association of radon gas exposure to lung cancer is described below:[27][28]
- Radon is a colorless and odorless gas generated by the breakdown of radioactive radium (decay product of uranium) found in the Earth's crust. The radiation decay products ionize genetic material, causing mutations that sometimes turn cancerous.
- Radon exposure is the second major cause of lung cancer following smoking.
- The mechanism of lung damage following radon exposure is not thought to be due to the radon gas itself, but due to the short-lived alpha decay products that cause cellular damage and DNA mutations.
Asbestos
- Asbestos exposure is associated with many lung diseases, including lung cancer.[29]
- Tiny asbestos fibers released into the air are breathed into the lungs. The fibers become lodged in the lungs and are stuck for an indefinite amount of time. They can eventually lead to scarring and inflammation.
Viruses
- Viruses known to be associated with the development of lung cancer in animals and humans include:[30][31][32][33][34][35]
- These viruses may affect the cell cycle and inhibit apoptosis, allowing uncontrolled cell division.
- HIV has also been thought to increase the risk of developing lung cancer. Although the mechanism is unknown, HIV is thought to be associated with a state of chronic lung inflammation that may potentiate cellular damage and DNA mutations.
Infection and Inflammation
- There may be a correlation between general inflammation of lung tissue and the development of lung cancer.[35]
- Neutrophils are released in response to bacterial infection and are considered to be the initial responders during inflammation.
- The hypothesis is that neutrophils may activate reactive oxygen or nitrogen species, which can bind to DNA and lead to genomic alterations. Accordingly, inflammation may be thought of as an initiator or promoter of lung cancer development. Also, tissue repair from inflammation is associated with cellular proliferation. During cellular proliferation there may be errors in chromosomal replication that can cause further DNA mutation.
- Angiogenesis, a significant process during tumor growth, may be promoted by chronic states of inflammation, which often require increased blood flow to sites of inflammation.
References
- ↑ Kanwal, Madiha; Ding, Xiao-Ji; Cao, Yi (2017). "Familial risk for lung cancer". Oncology Letters. 13 (2): 535–542. doi:10.3892/ol.2016.5518. ISSN 1792-1074.
- ↑ Kadara, H.; Scheet, P.; Wistuba, I. I.; Spira, A. E. (2016). "Early Events in the Molecular Pathogenesis of Lung Cancer". Cancer Prevention Research. 9 (7): 518–527. doi:10.1158/1940-6207.CAPR-15-0400. ISSN 1940-6207.
- ↑ Raso, Maria Gabriela; Wistuba, Ignacio I. (2007). "Molecular Pathogenesis of Early-Stage Non-small Cell Lung Cancer and a Proposal for Tissue Banking to Facilitate Identification of New Biomarkers". Journal of Thoracic Oncology. 2 (7): S128–S135. doi:10.1097/JTO.0b013e318074fe42. ISSN 1556-0864.
- ↑ Wistuba II, Gazdar AF (2006). "Lung cancer preneoplasia". Annu Rev Pathol. 1: 331–48. doi:10.1146/annurev.pathol.1.110304.100103. PMID 18039118.
- ↑ Devarakonda, Siddhartha; Morgensztern, Daniel; Govindan, Ramaswamy (2015). "Genomic alterations in lung adenocarcinoma". The Lancet Oncology. 16 (7): e342–e351. doi:10.1016/S1470-2045(15)00077-7. ISSN 1470-2045.
- ↑ Kadara H, Scheet P, Wistuba II, Spira AE (July 2016). "Early Events in the Molecular Pathogenesis of Lung Cancer". Cancer Prev Res (Phila). 9 (7): 518–27. doi:10.1158/1940-6207.CAPR-15-0400. PMID 27006378.
- ↑ Auerbach, Oscar; Stout, A. P.; Hammond, E. Cuyler; Garfinkel, Lawrence (1961). "Changes in Bronchial Epithelium in Relation to Cigarette Smoking and in Relation to Lung Cancer". New England Journal of Medicine. 265 (6): 253–267. doi:10.1056/NEJM196108102650601. ISSN 0028-4793.
- ↑ Fong, KM (Oct 2003). "Lung cancer. 9: Molecular biology of lung cancer: clinical implications". Thorax. BMJ Publishing Group Ltd. 58 (10): 892–900. PMID 14514947. Unknown parameter
|coauthors=
ignored (help) - ↑ Aviel-Ronen, S (Jul 2006). "K-ras mutations in non-small-cell lung carcinoma: a review". Clinical Lung Cancer. Cancer Information Group. 8 (1): 30–38. PMID 16870043. Unknown parameter
|coauthors=
ignored (help) - ↑ Karachaliou N, Mayo C, Costa C, Magrí I, Gimenez-Capitan A, Molina-Vila MA, Rosell R (2013). "KRAS mutations in lung cancer". Clin Lung Cancer. 14 (3): 205–14. doi:10.1016/j.cllc.2012.09.007. PMID 23122493.
- ↑ Devereux, TR (Mar 1996). "Molecular mechanisms of lung cancer. Interaction of environmental and genetic factors". Chest. American College of Chest Physicians. 109 (Suppl. 3): 14S–19S. PMID 8598134. Retrieved 2007-08-11. Unknown parameter
|coauthors=
ignored (help) - ↑ Engels, EA (Jul 2007). "Systematic evaluation of genetic variants in the inflammation pathway and risk of lung cancer". Cancer Research. American Association for Cancer Research. 67 (13): 6520–6527. PMID 17596594. Unknown parameter
|coauthors=
ignored (help) - ↑ Wenzlaff, AS (Dec 2005). "CYP1A1 and CYP1B1 polymorphisms and risk of lung cancer among never smokers: a population-based study". Carcinogenesis. Oxford University Press. 26 (12): 2207–2212. PMID 16051642. Unknown parameter
|coauthors=
ignored (help) - ↑ Son, JW (Sep 2006). "Polymorphisms in the caspase-8 gene and the risk of lung cancer". Cancer Genetics and Cytogenetics. 169 (2): 121–127. PMID 16938569. Unknown parameter
|coauthors=
ignored (help) - ↑ Yin, J (May 2007). "The DNA repair gene XRCC1 and genetic susceptibility of lung cancer in a northeastern Chinese population". Lung Cancer. 56 (2): 153–160. PMID 17316890. Unknown parameter
|coauthors=
ignored (help) - ↑ Dela Cruz CS, Tanoue LT, Matthay RA (2011). "Lung cancer: epidemiology, etiology, and prevention". Clin. Chest Med. 32 (4): 605–44. doi:10.1016/j.ccm.2011.09.001. PMC 3864624. PMID 22054876.
- ↑ Hecht SS (1999). "Tobacco smoke carcinogens and lung cancer". J. Natl. Cancer Inst. 91 (14): 1194–210. PMID 10413421.
- ↑ Kluger, R. (1996). Ashes to ashes: America's hundred-year cigarette war, the public health, and the unabashed triumph of Philip Morris. New York: Alfred A. Knopf.
- ↑ Proctor, Robert (2000). The Nazi war on cancer. Princeton, N.J. Oxford: Princeton University Press. ISBN 978-0691070513.
- ↑ Morabia, Alfredo (2012). "Quality, originality, and significance of the 1939 "Tobacco consumption and lung carcinoma" article by Mueller, including translation of a section of the paper". Preventive Medicine. 55 (3): 171–177. doi:10.1016/j.ypmed.2012.05.008. ISSN 0091-7435.
- ↑ Mueller F. Tabakmissbrauch und Lungencarcinom. Z. Krebsforsch. 1939;49:57–85.
- ↑ Wynder, E. L. (1994). Prevention and cessation of tobacco use: Obstacles and challenges. J. Smoking-Related Dis. 5(Suppl. 1), 3–8.
- ↑ Hanspeter Witschi ITEH and Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California 95616
- ↑ Hecht, S (Oct 2003). "Tobacco carcinogens, their biomarkers and tobacco-induced cancer". Nature Reviews. Cancer. Nature Publishing Group. 3 (10): 733–744. doi:10.1038/nrc1190. PMID 14570033. Retrieved 2007-08-10.
- ↑ Nordquist, LT (Aug 2004). "Improved survival in never-smokers vs current smokers with primary adenocarcinoma of the lung". Chest. American College of Chest Physicians. 126 (2): 347–351. PMID 15302716. Retrieved 2007-08-10. Unknown parameter
|coauthors=
ignored (help) - ↑ Peto R, R (2006). Mortality from smoking in developed countries 1950–2000: Indirect estimates from National Vital Statistics. Oxford University Press. ISBN 0-19-262535-7. Retrieved 2007-08-10. Unknown parameter
|coauthors=
ignored (help) - ↑ Catelinois, O (May 2006). "Lung Cancer Attributable to Indoor Radon Exposure in France: Impact of the Risk Models and Uncertainty Analysis". Environmental Health Perspectives. National Institute of Environmental Health Science. 114 (9): 1361–1366. doi:10.1289/ehp.9070. PMID 16966089. Retrieved 2007-08-10. Unknown parameter
|coauthors=
ignored (help) - ↑ University of Minnesota.http://enhs.umn.edu/hazards/hazardssite/radon/radonmolaction.html#Anchor-Molecular-23240/
- ↑ Järvholm, Bengt; Åström, Evelina (2014). "The Risk of Lung Cancer After Cessation of Asbestos Exposure in Construction Workers Using Pleural Malignant Mesothelioma as a Marker of Exposure". Journal of Occupational and Environmental Medicine. 56 (12): 1297–1301. doi:10.1097/JOM.0000000000000258. ISSN 1076-2752.
- ↑ Leroux, C (Mar–Apr 2007). "Jaagsiekte Sheep Retrovirus (JSRV): from virus to lung cancer in sheep". Veterinary Research. 38 (2): 211–228. PMID 17257570. Unknown parameter
|coauthors=
ignored (help) - ↑ Palmarini, M (November 2001). "Retrovirus-induced ovine pulmonary adenocarcinoma, an animal model for lung cancer". Journal of the National Cancer Institute. Oxford University Press. 93 (21): 1603–1614. PMID 11698564. Retrieved 2007-08-11. Unknown parameter
|coauthors=
ignored (help) - ↑ Cheng, YW (Apr 2001). "The association of human papillomavirus 16/18 infection with lung cancer among nonsmoking Taiwanese women". Cancer Research. American Association for Cancer Research. 61 (7): 2799–2803. PMID 11306446. Retrieved 2007-08-11. Unknown parameter
|coauthors=
ignored (help) - ↑ Zheng, H (May 2007). "Oncogenic role of JC virus in lung cancer". Journal of Pathology. 212 (3): 306–315. PMID 17534844. Unknown parameter
|coauthors=
ignored (help) - ↑ Giuliani, L (Sep 2007). "Detection of oncogenic viruses (SV40, BKV, JCV, HCMV, HPV) and p53 codon 72 polymorphism in lung carcinoma". Lung Cancer. 57 (3): 273–281. PMID 17400331. Unknown parameter
|coauthors=
ignored (help) - ↑ 35.0 35.1 Eric A Engels.11/30/11. Inflammation in the development of lung cancer:epidemiological evidence.Expert Review of Anticancer Therapy.Apr.2008.p605