[Radiation-related CML].

The clinical, cytogenetic and molecular-genetic findings of 55 patients with radiation related chronic myelocytic leukemia(CML) among the Hiroshima atomic bomb survivors were compared with 167 CML patients without a history of the radiation exposure. The retrospective analysis of the hematological data kept at the laboratory center where the survivors had been examined twice a year revealed a possible chronologic sequence in appearance of clinical and laboratory findings characteristic of CML. No particular differences were observed between the two groups in the incidence of Philadelphia chromosome and break points of the BCR gene, contrasting with those of radiation-related acute myelocytic leukemia which showed complex chromosome abnormalities without specific type of translocations, especially of 8;21 and 15;17, and a high incidence of genetic instability of the leukemic cells.