t(1;19)(q23;p13) in a case of acute monocytic leukemia

Translocation (1;19)(q23;p13) is considered a specific chromosome aberration in acute lymphoblastic leukemia (ALL). We report a case of M5 acute nonlymphocytic leukemia (ANLL) with t(1;19). In all mitoses studied from peripheral blood (PB) cells, the pathological karyotype 51,XX, t(1;19)(q23;p13),+8, +der(19)t(1;19)(q23;p13),+3mar was detected. No rearrangement of the E2A gene was detected. We believe this case shows that cytogenetically indistinguishable aberrations may be accompanied by quite different molecular events.