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Molecular-cytogenetic aberrations in B-cell adult acute lymphoblastic leukemia (B-ALL) - frequency and correlation with immunophenotype. 2006

Milena Velizarova, and Dora Popova, and Evgenii Hadjiev, and Kamelia Aleksandrova, and Ivanka Dimova, and Boriana Zaharieva, and Stavri Toshkov, and Mimoza Staneva, and Djansaran Hodjajik, and Marin Penev, and Draga Toncheva

B-cell acute lymphoblastic leukemia (B-ALL) accounts for 20-30% of acute leukemias in adults. Combined application of data from immunophenotyping, karyotyping and molecular analyses allows a better understanding of this heterogeneous disease. We studied 30 adult patients with newly diagnosed B-ALL by conventional cytogenetics, fluorescent in situ hybridization (FISH) and immunophenotyping analyses. We report statistically significant prevalence of structural aberrations (43%) over numerical changes (17%) (p=0.02). The most frequent structural changes were t(9;22)(q34;q11)/bcr-abl-17%, t(8q24)/C-MYC-10%, t(11q23)/MLL-6%, del 4p-6%, del12p-3%, and t(1;19)-3%. Complex karyotype was found in 17% and normal karyotype in 30%. The most frequent immunophenotype was of common B-ALL (43%), and cytogenetic and/or molecular abnormalities were found in 78% of them. We distinguished a relatively high incidence (17%) of mature B-ALL and 60% of them were associated with t(8;14)/C-MYC. We established association of cytogenetic aberrations with immunophenotype only in mature B-ALL. The other immunophenotypes are characterized by genetic heterogeneity and the presence of cytogenetic abnormalities unusual for adult B-ALL - trisomy 8 and t(1;19)(q23;p13).