RESUMO
The gross structure and the expression of the c-myc oncogene were analyzed in primary cells from 15 acute lymphoblastic leukemia patients. Southern blot analysis was used to detect possible alterations in the structure of this gene. Alterations (rearrangement and/or amplification) were observed in seven of the 15 samples studied. When the expression of MYC protein was evaluated by Western blot analysis, we found no correlation between c-myc gene alterations and p67 c-myc, which was expressed in the 15 samples studied. The analysis of expression also revealed various MYC-related proteins (115, 110 and 60 kD). These proteins were expressed at variable levels in all leukemic cells, other transformed cells, and in normal peripheral blood lymphocytes (PBL) induced to proliferate with interleukin 2. We detected the 110 kD and 40 kD MYC-related proteins in fresh normal PBL and in samples from patients in complete remission. These studies indicate that the c-myc alterations and protein expression are unrelated to percentage of leukemic blasts, cell morphology or immunophenotype. Our work shows that the expression of MYC-related proteins from 115, 60 and 40 kD is associated with mechanisms of cell activation, and perhaps these proteins may play a role in cellular proliferation-transformation.