Bleomycin-induced chromosome damage in lymphocytes indicates inefficient DNA repair capacity in breast cancer families

In vitro mutagen susceptibility has been observed as a predictor of cancer risk. To evaluate susceptibility to mutagen, we have studied the response t o in vitro bleomycin (BLM) treatment in cultured peripheral blood lymphocyt es (PBL) of 9 breast cancer families (BCFs). Eleven breast cancer patients (BCPs) and 36 healthy blood relatives (HBRs) from BCFs were included in the study. Data were compared with 22 healthy control women. The frequencies o f chromosomal aberrations were evaluated after exposure to BLM in the last five hours. Mean frequency of BLM-induced chromosomal aberrations per cell (CA) observed among BCPs was significantly higher as compared to their HBRs as well as control subjects. Moreover, mean BLM-induced CA/cell value obse rved for HBRs was also significantly higher than that of control subjects. In comparison to controls, it was observed that there was four times more c ancer risk in BCPs (OR=4.148, 95% CI=5.83-687.46) and 2.5 times more cancer risk in HBRs (OR=2.67, 95% CI=5.31-39.25). Lymphocytes from 90% of BCPs an d 69% of HBRs were found to he sensitive to BLM (using a cutoff value = con trols group mean + 1SD). Thus, lymphocytes of BCPs and their HBRs were more sensitive to BLM exposure as compared to controls. Our finding indicated i nefficient DNA repair capacity in BCFs. The HBRs in BCFs, having increased BLM-sensitivity, may be at higher risk to develop a similar cancer.