Association of in Vitro Radiosensitivity and Cancer in a Family with Acute Myelogenous Leukemia1

The y-ray sensitivity of skin fibroblasts from six members of a cancer family was investigated using a colony-forming assay. Fibroblasts from the three members with cancer (two sisters with acute myelogenous leukemia and the mother with cervical carcinoma) showed a significant (p < 0.05) increase in radiosensitivity, while three members without cancer (the father and two sons) showed a normal radioresponse. The possibility that the increased y-ray sensitivity was due to defective DMA repair was investigated using assays for DNA repair replication, single-strand break rejoining, and removal of enzyme-sensitive sites in y-irradiated DNA. Results of these assays indicate that the kinetics of enzymatic repair of radiogenic DNA damage in general, and the rejoining of single-strand scissions and exci sion repair of base and sugar radioproducts in particular, were the same in the cell lines from the sensitive and clinically normal family members.