Impact of trisomy 8 on cytobiological and clinical features of acute myelomonocytic and monocytic leukemia.

To evaluate the impact of trisomy 8 on cytobiological and clinical features of acute myelomonocytic and monocytic leukemia (M(4), M(5)), a total of 56 cases of acute myelomonocytic and monocytic leukemia were investigated. Karyotypes were analyzed by G-banding or R-banding. The immunotypes in all cases were detected by flow cytometry. And the clinical characteristics at the first visit were analyzed retrospectively. The results showed that thirty-four of 56 (60.7%) patients had normal cytogenetics; 10 (17.9%) patients had trisomy 8 in their karyotypes, including 3 (5.4%) patients with trisomy 8 as the sole aberration; and 12 (21.4%) patents had other cytogenetic abnormalities (except trisomy 8). All trisomy 8 cases demonstrated a increased expression frequency of surface markers of myeloid progenitor cells CD34 (P < 0.01) and CD117 (P < 0.05) and a decreased expression frequency of surface markers of mature monocytes CD11c (P < 0.01) and CD14 (P < 0.05), compared with normal cytogenetics cases. Patients with trisomy 8 were slightly older (P < 0.05), which had lower percentages of peripheral blasts (P < 0.05) and lower WBC (P < 0.05) than the patients without trisomy 8. Patients with trisomy 8 had a shorter disease-free survival time than that of patients with normal cytogenetics (P < 0.05). It is concluded that trisomy 8 may play an important role in the pathogenesis and progression of acute myelomonocytic/monocytic leukemia (M(4)/M(5)), whic seems to be related with a block in differentiation of monocytes. Therefore, trisomy 8 may be an adverse prognostic factor for patients with M(4) or M(5).