WBR0185
| Author | [[PageAuthor::Ogheneochuko Ajari, MB.BS, MS [1] (Reviewed by Serge Korjian)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Genetics, MainCategory::Pathology |
| Sub Category | SubCategory::Oncology |
| Prompt | [[Prompt::An 7-year-old boy is brought by his parents to the emergency department for severe left leg pain that started 2 days prior to presentation. His mother reports that the child has been very tired for the past few weeks. She also explains that he son has lost a lot of weight, and has been running out of breath with minimal activity recently. Upon further questioning, the child denies any trauma to his leg. On physical exam, you notice an ill appearing child with abdominal swelling and petechiae on the upper and lower extremities. A CBC is drawn and shows a Hb of 8.5 g/dL, hematocrit of 25, and a WBC count of 75,000/uL. Which of the following findings is considered a good prognostic marker in this patient?]] |
| Answer A | AnswerA::t(12;21) translocation |
| Answer A Explanation | AnswerAExp::t(12, 21) translocation offers a better or favorable prognosis in ALL and this aids in the selection of therapies for cases of ALL |
| Answer B | AnswerB::t(11;22) translocation |
| Answer B Explanation | AnswerBExp::t(11,22) translocation is associated with Ewing’s sarcoma |
| Answer C | AnswerC::Ten-eleven translocation 2 (TET2) |
| Answer C Explanation | AnswerCExp::Ten-eleven translocation 2 (TET2) is a gene located on chromosome 4q24. Mutations’ involving this gene is found in myeloid malignancies including myelodysplastic syndromes, CML, AML. It is not a prognostic indicator in ALL |
| Answer D | AnswerD::TdT |
| Answer D Explanation | AnswerDExp::TdT is a protein expressed early in the development of pre-T and pre-B cells but it is not a prognostic marker of the disease |
| Answer E | AnswerE::Isocitrate dehydrogenase 1/2 (IDH1/IDH2) |
| Answer E Explanation | [[AnswerEExp::Isocitrate dehydrogenase 1 (IDH1) is a gene located in chromosome 2q33.3 while IDH2 is located in chromosome 15q26.1. These genes are responsible for encoding enzymes catalyzing oxidative decarboxylation of isocitrate to alpha ketoglutarate. Mutations in this gene confer poor prognosis in certain subsets of AML]] |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy, accounting for approximately 30% of all cancers in patients younger than 14 years of age. It is a clonal lymphoid stem cell disease.
It could be of the early pre-B-cell leukemia or the T-cell ALL. T(12,21) translocation is the most common structural chromosome change on childhood cancer and is exclusively associated with the B-cell precursor subset of ALL. The translocation generates TEL-AML1 (ETV6-RUNXI) fusion gene, which is associated with a more favorable prognosis as evidenced by a significantly lower relapse rate. Evaluation of this and other prognostic markers helps in selecting low toxicity versus high toxicity therapies Educational Objective: t(12,21) translocation is a good prognostic marker in cases of ALL |
| Approved | Approved::Yes |
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| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |