Analysis of repair of abasic sites in early onset breast cancer patients

Defective DNA repair has been suggested as a possible predisposing factor f or breast cancer. We have investigated the repair of the frequent endogenou s lesions abasic sites in sporadic early onset breast cancer patients and m atched control individuals. No significant difference was observed between the abasic site repair capacities of peripheral blood lymphocytes from case s and controls. Repair of abasic sites was also studied in tumor and surrou nding normal tissues of the patients. The 2 tissues showed marked differenc es in histology and protein composition with a fibro-collagenous component varying from sample to sample but invariably higher in normal tissues as co mpared with the adjacent tumor. These differences involved the need to calc ulate the repair activities of tissues on the basis of cellular DNA content for comparison purposes. After doing so, tumor and normal tissues exhibite d similar abasic site repair capacities, whereas lymphocytes showed a repai r capacity significantly lower than tissues. We conclude that early onset s poradic breast cancer patients show no evident defect in repair of abasic s ites at the level of both lymphocytes and tumor. (C) 2000 Wiley-Liss, Inc.