Immunohistochemical study on expression of p185 and p16 proteins in benign and malignant breast tissues

To study the biological significance of p185 and p16 expression in benign and malignant breast tissues,their proteins were detected immunohistochemically in 37 benign breast tissues,including 17 cases without epithelial hyperplasia and 20 with hyperplasia,and 59 breast carcinomas.The results showed that in the groups of non-hyperplasisa,hyperhlasia,and breast cancer,p185 positive rates were 0%,15%and 47% respectively(p0.01),and p16 positive rates were 41%,30%and 34% respectively.No relationship was found between p185 and p16 expression.p185 overexpression and reduced p16 expression tended to be more frequently found in carcinoma in situ,early invasive carcinoma and invasive carcinoma with prominent intraductal carcinoma than in invasive carcinoma NOS.There was also a tendency towards more expression of both proteins with the increase of histologic grade and tumor size.In cases with lymph-node involved ,p185 positive rate was 64% which was twice that of the cases without lymph-node metastasis(p0.05).The results suggested that p185 overexpression and reduced p16 expression might take roles independently in carcinogenesis and development of breast cancer.p185 is an important tumor marker of breast cancer.