Abstract: Objective:To investigate the methylation of p16 gene promoter in patients with breast cancer tissue.Methods:The methylation status of p16 gene promoter in tumor tissue samples was detected through methylation-specific polymeras chain reaction (MS-PCR).Results:The positive rate of p16 gene promoter methylation was 30.5% in tumor tissue.The aberrant methylation of p16 gene promoter in tumor tissues had no correlation to patient's tumor staging,tumor size,histological type,menstruation status,lymphonode metastasis,hormone receptor and family history (P>0.05).Conclusions:p16 gene promoter methylation takes part in the breast cancer's carcinogenesis and this is an earlier event.Methylation of p16 gene promoter is probably used as molecular biology marker in early diagnosis and screen of breast cancer.