Chromosomes and causation of human cancer and leukemia. L. Cytogenetics of leukemias complicating other diseases.

Complicating (secondary) leukemias in 20 patients, 18 of whom had various forms of neoplasia treated with chemotherapy and/or radiation, have been examined in regard to the karyotypic findings present in the leukemic cells of the marrow. In addition, the published cases of complicating leukemia have been tabulated. Based on the results of the present study and those in the literature it appears that chromosomes #3 and #17 should be stressed as being nonrandomly involved in complicating leukemia in addition to the previously stressed chromosomes #5 and #7. The results of the present study are discussed in relation to those reported in the literature, and stress put on the significance of cytogenetic changes in relation to possible causative factors of the complicating leukemia. The hypothesis is advanced that these nonrandom chromosome changes may reflect causative specificity of the complicating leukemia and that a concerted effort must be made to obtain more cogent information on the role of noxious agents in the causation of complicating leukemia.