title: Minimally differentiated acute myeloid leukemia (AML M0): clinico-biological findings of 29 cases.
abstract: Twenty-nine cases of minimally differentiated acute myeloid leukemia or AML M0 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, TcRbeta, 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 cases. Of these, 6 involved chromosomes 5, 7 and 8, t(9;22), confirmed by the BCR/ABL transcript, was detected in one case. Rearrangements of the TcRbeta and IgH chains were observed in 3 and 2 cases, respectively. No AML1/ETO and CBFB-MYH11 transcripts were found. Twelve out of 27 patients (44%) achieved a complete remission (CR) (in 2 cases after rescue therapy). Seven early (range 1-9 months) and one late (32 months) relapses were observed. Five patients are alive, but only the 4 who underwent bone marrow transplantation are in persistent first CR. In conclusion, AML M0 is a subtype of AML antigenically well detectable, endowed with many adverse parameters (older age, TdT and CD34 expression, resistance to apoptosis, unfavorable cytogenetic abnormalities) and poor prognosis. A very aggressive consolidation treatment can be useful to improve the outcome.
authors.affiliation: Department of Hematology, I.R.C.C.S.-Casa Sollievo Della Sofferenza Hospital, San Giovanni Rotondo, Italy. nicola54@libero.it
authors.forename: N
authors.initials: N
authors.lastname: Cascavilla
authors.forename: L
authors.initials: L
authors.lastname: Melillo
authors.forename: G
authors.initials: G
authors.lastname: D'Arena
authors.forename: M M
authors.initials: MM
authors.lastname: Greco
authors.forename: A M
authors.initials: AM
authors.lastname: Carella
authors.forename: M R
authors.initials: MR
authors.lastname: Sajeva
authors.forename: G
authors.initials: G
authors.lastname: Perla
authors.forename: R
authors.initials: R
authors.lastname: Matera
authors.forename: M M
authors.initials: MM
authors.lastname: Minervini
authors.forename: M
authors.initials: M
authors.lastname: Carotenuto
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D016026:Bone Marrow Transplantation; D005260:Female; D015321:Gene Rearrangement; D006801:Humans; D016130:Immunophenotyping; D007621:Karyotyping; D007951:Leukemia, Myeloid / Q000145:classification* / Q000235:genetics / Q000276:immunology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D016019:Survival Analysis