AN EPIDEMIOLOGY AND MOLECULAR GENETIC STUDY ON BREAST CANCER SUSCEPTIBILITY

Obieaites. To investigate the genetic susceptibility for breast cancer of Chinese, a hospital-besed case-control study, pedigree survey and molecular genetic study were conducted. Methods. Logistic regression model and stratification methods were used in the risk factors analysis. Li-Mantel-Gart and Falconer methods were used to analyze the segregation ratio and heritability. Polymemse chain reaction (PCR) and polyacrylamide gel electrophoresis were used to detect AI, G-banding technique was used to detect the chromosome aberration of peripheral blood lymphocyte. Results. Family history of breast cancer is related to enhanced breast cancer risk significantly, OR is 3.905(95% CI = 1.079—14.13), and it widely interacts with other risk factors. Accumulative incidence of breast cancer in first degree relatives is 9.99%, which is larger than that in second, third degree and non-blnod relatives. Segregation ratio is 0.021, heritability among first degree relatives is 35.6 ± 5.8%. Frequencies of LDH at BRCA1 and BRCA2 loci in sporadic breast cancer are 6.12% and 5.77% respectively. In the sibs, both of them show LOH at D13S173 locus, and high frequencies of chromosome abermtions were observed.Condusions. Genetic susceptibility contributes to breast cancer occurrence of Chinese, and its racial variation may be one of the important reasons for the large difference of incidence between western and eastern countries.