Comparison of genetic changes between interphase and metapbase nuclei in monitoring CML and APL treatment using DC-FISH technique

Abstract

In leukemias, the monitoring techniques on the response after the treatment have clinical importance for evaluating new therapeutic approaches and identifying the risk of relapse. In this study, genetic changes before and after chemotherapy in interphase and metaphase nuclei of bone morrow of adults with provisional diagnosis of leukemia were compared to understand the molecular characterization and pathogenesis of the leukemia for the classification of diagnosis and prognosis. We examined bone morrow cells of 47 chronic myeloid leukemia (CML) cases (29 of 47 at the time of diagnosis, 31 of 47 after chemotherapy) with the bcr/abl translocation probes and of 10 acute promyelocytic leukemia (APL) cases (7 of 10 at the time of diagnosis, 4 of 10 after chemotherapy) with the PML/RARalpha translocation probes by using dual color-flourescence in situ hybridization (DC-FISH). For each case, 400 interphase nuclei and 11 to 25 metaphases nuclei were analysed. The ratios of translocations before and after chemotherapy were compared between interphase and metaphase nuclei. After chemotherapy, though, translocations were detected in interphase nuclei of 29 of the 31 CML and 4 of the 4 APL cases, these translocations were determined in metaphase nuclei of only 14 of the 31 CML and 1 of the 4 APL cases with very low ratios (p < 0.01). The results showed that the rates of translocation positive interphase nuclei were higher than the rates of translocation positive metaphase nuclei (p < 0.01) after chemotherapy, so there may be some factors effecting proliferative activity of metaphase formation in leukemias.