In accordance with the close association of BRCC3 mutations with t(8;21)(q22;q22.1) we found a pro-proliferative effect of BRCC3 inactivation in the t(8;21)(q22;q22.1) AML cell lines Kasumi-1 and SKNO-1 but not in a cell line without t(8;21)(q22;q22.1). The gene discussed is BRCC3; the disease is acute myeloid leukemia.