Missing Y chromosome in 2 patients with chronic myelocytic leukemia

Cytogenetic studies of Hodgkin's disease. Analysis of involved lymph nodes from 12 patients

Cytogenetic studies were performed on 12 involved lymph nodes from Hodgkin's disease patients utilizing conditioned medium from 12-O-tetradecanoylphorbol-13-acetate-staphylococcus enterotoxin A induced mononuclear cells. The majority of cells analyzed had a normal karyotype. An unusually high rate of nonclonal karyotypic abnormalities was noted in most cultures. Clonal abnormalities involving chromosomes 3 and 21 were noted in two patients. Cytogenetic analysis of cultures stimulated with conditioned medium or specific growth factors may lead to a better understanding of the genetic mechanisms involved in Hodgkin's disease.

Tetraploidy and Y chromosome loss in acute mixed-lineage leukemia

An unusual case of acute leukemia with mixed phenotype was followed up from diagnosis to death for about 12 months. The first cytogenetic examination revealed about 80% of the bone marrow cells in the diploid and 20% in the tetraploid range. After two courses of induction therapy, complete remission was achieved within 2 months. At this time the tetraploid cells were reduced to 3%, but 50% of the mitoses showed a Y chromosome loss, while the other mitoses had a diploid karyotype. Early intensification therapy was given 6 weeks later with slow recovery of blood counts. After four months a sharp decrease of the number of Y-missing mitoses was observed, while the marrow remained in full remission. Two months later a relapse occurred and the patient died. At this time the -Y clone had dropped to 2% and the tetraploid clone was totally absent. We conclude from these findings that the diploid clone was the most malignant one, whereas the -Y cells were probably not directly involved in the leukemic process.