Unusual cytogenetic findings in two patients with t(4;11) acute leukemia.

Unusual cytogenetic findings are described in two patients with acute leukemia and rearrangements involving chromosomes 4 and 11. Both patients had clinical and phenotypic features often found in leukemia with t(4;11)(q21;q23). At initial diagnosis, one patient showed a standard t(4;11) with duplication of the 4q-translocation derivative. The latter finding has been described previously in a few patients with t(4;11) in association with disease progression. By analogy with the Ph1 chromosome in chronic myelogenous leukemia, duplication of the 4q-suggests that this derivative is the critical recombinant in the t(4;11). The second patient has a novel complex translocation, t(4;11;15)(q21;q23;q21). Analysis of this variant translocation implies that the 11q+ is the consistent chromosome rearrangement in this type of leukemia. The apparent contradiction of the findings in these and other relevant reported cases reviewed here suggests that genes on both the 11q+ and 4q- recombinant chromosomes are important, in either the etiology or the progression of this disease.