FAMILIAL CLUSTERING OF BREAST-CANCER - POSSIBLE INTERACTION BETWEEN DNA-REPAIR PROFICIENCY AND RADIATION EXPOSURE IN THE DEVELOPMENT OF BREAST-CANCER

The capacity of peripheral blood lymphocytes to repair X-ray-induced D NA damage, manifest as chromatid damage 30-90 min after G(2)-phase X-i rradiation, was measured among available members of a family exhibitin g a cluster of breast-cancer cases occurring in one generation. The ca ncer patients had been exposed to repeated chest fluoroscopic examinat ions during early childhood and adolescence. The development of breast cancer was correlated with DNA repair proficiency and history of radi ation exposure. The results of the family study provide preliminary su pport for the hypothesis that a deficiency in repair of X-irradiation DNA damage may be a susceptibility factor for the development of breas t cancer. This hypothesis, however, requires confirmation in a larger study. Studying the combined effect of susceptibility factors and envi ronmental exposures may enhance our knowledge of the etiology of breas t cancer and provide leads for effective prevention strategies aimed a t reducing exposures or altering susceptibility to unavoidable exposur es. (C) 1995 Wiley-Liss, Inc.