The significance of studies of leukemic cell kinetic parameters in children with acute leukemia
Objective evaluation of the kinetic status of leukemic cells in children with acute leukemias is discussed. The authors studied the expression of cell cycle proteins (D and E cyclins, cdk2 and cdk4 cyclin-dependent kinases, E2F1 transcription factor, retinoblastoma gene protein - PRb and growth fraction) in leukemic cells of 79 children with acute lymphoblastic leukemia (ALL) and 37 children with acute myeloid leukemia. Peripheral blood lymphocytes from 7 donors served as the control. Proteins were measured by the standard Western blotting method. Cell growth fraction (Ki67) was measured by flow cytofluorometry. Drug sensitivity of leukemic cells was studied by the MTT-assay. Study of the kinetic status of leukemic cells showed that high values of leukemic cell growth fraction in B-cell lineage ALL before therapy can be regarded as a prognostic factor predicting poor efficiency of induction therapy. Low expression of cdk2, cdk4, D and E cyclins and high value of leukemic cell growth fraction before therapy were characteristics of ALL patients who developed relapses. Prognostic factors for relapse-free course are high expression of cdk2, cdk4, D and E cyclins, and low value of blast cell growth fraction before therapy. The data are discussed and compared with published reports.