Abstract

Cyclin D1, a cell cycle regulator essential for G1 phase progression, is a candidate proto-oncogene implicated in pathogenesis of several human carcinomas including breast carcinoma. We studied the cyclin D1 expression in 101 cases of primary breast carcinoma tissues. The overexpression of cyclin D1 was immunohistochemically demonstrated in 34 (37.8%) of 90 cases of invasive breast carcinoma. Positive cyclin D1 staining was seen in 32 of 79 invasive ductal carcinomas, and 2 of 3 mucinous carcinomas. All 5 medullary carcinomas, 2 invasive lobular carcinomas, and 1 metaplastic carcinoma were negative. Cyclin D1 overexpression was observed in 9 of 11 ductal carcinoma in situ (DCIS). Normal epithelial components, either ductal or lobular, were not immunoreactive for cyclin D1. No significant correlations were observed between cyclin D1 immunoreactivity and other parameters including tumor size, clinical stage, nuclear or histologic grades, lymphatic or angioinvasion, lymph node metastasis, and immunohistochemical status of progesterone receptor, p53 and c-erbB-2. The overexpression of cyclin D1 was positively correlated with estrogen receptor status (p=0.025). Based on our results, the cyclin D1 protein aberration may play a role in tumorigenesis of breast carcinoma, but does not seem to have prognostic value in invasive breast carcinoma without hormonal treatment.

• Keywords: Breast carcinoma;Cyclin D1;Tumorigenesis;Estrogen receptor;Prognostic value;