A possible specific chromosome marker for monocytic leukemia: three more patients with t(9;11)(p22;q24) and another with t(11;17)(q24;q21), each with acute monoblastic leukemia.

An apparently balanced 9;11 reciprocal translocation with break points most likely at 9p22 and 11q24 was found in 3 patients with acute monocytic leukemia [M5 in the French-American-British (FAB) classification schema]. This translocation was not observed in 6 other patients with M5 acute nonlymphocytic leukemia (ANLL) or in chromosome studies on 143 patients with other types of ANLL. This study supports the previously published suggestion that such 9;11 translocations may be associated with some patients with M5 ANLL. In this report, we have also included a patient with M5 ANLL who had an 11;17 translocation with break points apparently at 11q24 and 17q21. Perhaps this is a variant translocation of chromosome No. 11, which may also be associated with monocytic leukemia.