An Epidemiology And Molecular Genetic Study On Breast Cancer Susceptibility

To investigate the susceptibility to breast cancer which involves in genetic and environmental aspects and to further research its molecular mechanisms, a study on epidemiology and molecular genetics for breast cancer was conducted.In our study, a hospital-based case-control study and pedigree survey were carried out. 313 cases of new diagnostic breast cancer were included in the study, which collected from the large hospitals of four cities from October 1996 to January 1997. One non-cancer patient at similar age was selected from the same hospital as control to match each case. Meanwhile, 313 pedigrees of proband and the same number control pedigrees were determined. The survey included approximately forty possible susceptible factors of breast cancer as well as detail pedigree information which contained the number of blood relatives in their three generations, the number of non-blood relatives and the state of their cancer occurrence.In the course of data analysis, statistic softwares of STATA(3.0), EPI and PPAP(3.0) were in use. Logistic regression models, the methods of Li-Mantel-Gart and Falconer were used respectively to analyze the possible susceptible factors, segregation ratio and the hereditability of breast cancer. In addition, we obtained 30 pairs of samples of tumor and peripheral blood from sporadic breast cancer patients and 2 pairs of samples from 2 familial breast cancer patients. Methods of SSCP analysis and DNA length polymorphism analysis were used to detect mutations in P53 gene, LOH in BRCA1 and BRCA2 gene region. G-binding technique was used to detect the chromosome aberration of peripheral blood lymphocyte for 2 familial breast cancer patients.The main results manifest as follows:1. Family history of breast cancer is related to enhanced breast cancer risk significantly, OR is 5.333(95%CI=1.550-18.347). After adjusting other risk factors by multiple factors analysis, it is still a dominant risk factor. The results suggests that if a woman has family history of breast cancer, she will have enhanced genetic susceptibility to breast cancer.