Among the FAB subtypes, the incidence of low BCL3 expression in M2 subtype was significantly higher than in the other subtypes M1/M2/M4/M5/M6/M7 (30/17, P = 0.006), whereas the frequency of high BCL3 expression in myelomonocytic/monocytic leukemia subtypes is mildly higher than leukemia with other cell types (26/50, P = 0.064). This evidence concerns the gene BCL3 and leukemia.