Minimally differentiated acute myeloid leukemia (AML M0): clinico-biological findings of 29 cases.

Twenty-nine cases of minimally differentiated acute myeloid leukemia or AML MO identified among 441 AML diagnosed in the last 12 years are reported. In all cases, flow cytometric analysis using a large panel of monoclonal antibodies and cytogenetic and molecular studies (IgH, TcRβ, BCR/ABL, AML1/ETO and CBFB-MYH11 rearrangements) were performed. Of the 29 patients, 27 were treated with intensive chemotherapy based on GIMEMA protocols. We noted a greater incidence of older (over 60 years) and male patients (52% and 65%, respectively). CD33, CD13, CD7 and TdT were expressed in 79.3%, 82.7%, 58.6% and 42.8% of cases, respectively. Antigenic MPO was present in 17 of 22 cases (77.3%). Most cases expressed CD34 (93.1%), HLA-DR (93.1%), CD117 (80%) and CD45RA (87%). CD45RO and CD90 were consistently negative. In all cases, we observed an up-expression of bcl-2 and a down-expression of CD95 with an inverse trend between the two markers (r -5253; p 0.03). Karyotypic abnormalities were demonstrated in 53.6% of case...