Abstract: Objective 　To investigate the expression of HPV16 DNA and p53 protein in breast cancer and explore its relation between expression of HPV16 infection with p53 and the carcinogenesis of breast cancer. Methods 　HPV16 DNA and p53 protein were detected by in situ hybridization and immunohistochemical staining in 50 cases of invasive duct carcinoma and 30 cases normal breast tissues . Results 　There was a significant difference in the expression of p53 protein between HPV16 DNA positive and HPV16 DNA negative breast carcinomas group s ( P < 0. 01), with a significant less detectable p53 protein in the HPV16 DNA positive cases . Conclusion 　Inactivation and degradation of wild type p53 protein by HPV16 infection in human mammary epithelial cells may play an important role in the pathogenesis human breast carcinomas.