BOF: Malignant (Leukaemia)

Which ONE of the following chromosomal translocations is characteristically associated with chronic myelomonocytic leukaemia (CMML)?

a) t(1; 22)

b) t(3;5)

c) t(4;11)

d) t(5;12)

e) t(9;22)

Answer:

d) t(5;12)

Explanation:

Balanced chromosomal translocations are rare in CMML, although associations with t(5;12) are reported, forming the tyrosine kinase fusion product TEL-PDGFRb. However, it is important to exclude chronic eosinophilic leukaemia in cases demonstrating this translocation, predominantly through the clinical phenotype, blood count and marrow findings. t(1; 22) is associated with childhood acute megakaryoblastic leukaemia, t(4;11) is a poor risk mutation in ALL particularly infant onset, t(9;22) produces the Philadelphia chromosome of CML and ALL and t(3;5) is associated with poor-risk AML (with MDS-related changes according to WHO 2008)

Reference:

Parikh SA, Tefferi A. Chronic myelomonocytic leukemia: 2012 update on diagnosis, risk stratification, and management. Am J Hematol 2012;87:610–619.