Acute mixed lineage leukemia and a t(6;14)(q25;q32) in two adults.

Acute mixed lineage leukemia (AMLL) is a rare form of leukemia in which both myeloid and lymphoid markers are present. Few chromosome abnormalities have been identified associated with this form of leukemia. A translocation involving the long arms of chromosomes 6 and 14 was previously described in four young individuals with acute leukemia and in three of these cases the diagnosis was mixed lineage. We identified a translocation involving the same chromosomes in two additional cases of adults with AMLL. The q32 breakpoint on chromosome 14 is shared by all six cases and five out of six cases also share the q25 breakpoint on chromosome 6. The rarity of the t(6;14) and the AMLL suggests a non-random association between these two events. The near cryptic appearance of the translocation might indicate that its occurrence is underestimated.