Variant forms of Philadelphia translocation in two patients with chronic myeloid leukemia.

During a 4-year period (December 1990-December 1994), among other diagnoses one hundred cases of chronic myeloid leukemia (CML) were analyzed in our department. We focused our attention on two cases with a variant form of Philadelphia translocation. Cytogenetic and molecular genetic studies were performed to resolve the status of BCR and ABL in the bone marrow or peripheral blood cells of the two CML patients with complex translocations involving chromosomes 3, 9, 22 and 9, 12, 22 respectively. In the first case the presence of Ph chromosome was detected cytogenetically, BCR-ABL translocation was detected by Southern hybridization. In the second case, only the PCR method showed BCR-ABL rearrangement. The second case, with a random variant form of Ph translocation, could be detected using different methods of clinical molecular genetics.