Sandbox: Langerhans

• Several cellular markers have been associated with poor disease prognosis, including expression of certain metalloproteinases and gelosin, a regulatory protein involved in the disassembly of actin microfilaments.41 Other factors for poor prognosis include extensive organ involvement and younger patient age at diagnosis.8 Younger age at diagnosis is associated with multisystem disease.

• The table below lists prognostic factors for Langerhans cell histiocytosis patients:

Prognostic Factor	Description
Age	Older age at the time of diagnosis is associated with a worse prognosis.
Gender	Males are associated with a worse prognosis when compared to females.
Performance status	Patient's poor performance status is associated with a worse prognosis.
Stage	Binet stages B and C or Rai stages 2-4 are associated with a worse prognosis.
Lymphocyte doubling time	A rapid lymphocyte doubling time is associated with a worse prognosis.
Genetic mutations	Deletion of chromosome 17 short arm and chromosome 11 long arm are associated with a worse prognosis.
Prolymphocytes percent	An increased percentage of prolymphocytes is associated with a worse prongnosis.
Histological analysis	Diffuse histology on bone marrow aspiration is associated with a worse prognosis.
Lactate dehydrogenase (LDH) level	Elevated level of LDH is associated with a worse prognosis.
β2-microglobulin level	Elevated level of β2-microglobulin level is associated with a worse prognosis.
Lymphocyte surface markers	Over expression of CD38 is associated with a worse prognosis.
Immunoglobulin (Ig)VH gene	The absence of IgVH gene mutation is associated with a worse prognosis.
Membrane-bound proteins	The expression of zeta-chain-associated protein kinase 70 (ZAP) is associated with a worse prognosis.