Research on DNA methylation in 5′CpG island of P16 gene and P16 expression in primary breast cancer and benign breast lesions / 重庆医科大学学报

ABSTRACT

Objective: To examine the involvement of methylation of p16 gene on the p16 status and tumor progression in primary breast cancer and the role of p16 protein in primary breast cancer.Methods: DNA was extracted from 45 cases of primary breast carcinomas and 15 cases of benign breast lesions.Polymerase chain reaction(PCR),using the extracted DNA and methylation-sensitive restriction enzymes(HpaⅡ?SacⅡ),was performed to detect the methylation of 5′CpG island in the p16 gene.The results were compared with the P16 expression by immunostaining.Results:(1) p16 was overexpressed in breast cancer.With the increase of histological grade of breast carcinomas,p16 expression decreased.In addition,the low expression of p16 in primary breast cancer was associated with tumor size and lymph node involvement.(2) Methylation of the CpG island of the p16 gene was inversely correlated with p16 expression in a subset of the primary breast carcinomas.With the increase of histological grade of breast carcinomas,DNA methylation was enhanced.Conclusion:Methylation of p16 gene may be the cause of loss of p16 expression.