Novel translocation (2;4) with consistent involvement of 2p23 in acute nonlymphocytic leukemia (M2).

A translocation involving the short arm of chromosome 2 and the long arm of chromosome 4 is described in three patients, all of whom had acute nonlymphocytic leukemia (M2). One patient had M2 de novo, one progressed from refractory anemia with excess blasts in transformation to M2 over a 4-month period, and one had had sideroblastic anemia 30 years prior to development of M2. In all three patients, the translocation involved the breakpoint p23 on chromosome 2, but the breakpoints on chromosome 4 varied between q25, q31, and q35. Translocations specifically involving 2p23 have not previously been described in leukemia, but more cases are required to identify a specific association with either the FAB type or prognosis.