Purpose: Cyclin D1 is a cell cycle regulatory gene emerging as a potentially significant oncogene in invasive breast cancers. In this study, we attempted to see the expression of Cyclin D1 in invasive ductal carcinomas of the breast in our population and correlate its expression with other known prognostic parameters.
Materials and methods: A total of 39 cases were selected from our case files from January 2011. Immunohistochemistry for Cyclin D1 was performed and interpreted as positive when >10% of the tumor cells expressed the marker with a moderate to strong intensity of staining. Clinicopathological parameters such as laterality, focality, tumor size, grade, ductal carcinoma in situ (DCIS), axillary lymph node (ALN) metastasis, hormone receptor status and human epidermal growth factor receptor 2 status were analyzed and correlated with Cyclin D1 expression.
Results: The patients' age ranged from 30 to 76 years (mean = 53.18). The tumors were unilateral and unifocal in 38 cases; one patient had bilateral synchronous tumors. The majority were grade2 (67.5%) and tumor size T2 (57.5%). Nearly 35% were associated with DCIS and 57.5% had ALN metastasis. Estrogen receptors (ER) and progesterone receptor (PgR) positivity was seen in 65% of the cases and 25% was triple negative. Cyclin D1 expression was seen in 67.5% of the cases in our study. Among the ER, PgR positive and Her-2 negative tumors, Cyclin D1 expression was seen in the majority of cases (92%) cases, whereas none of the triple negative tumors showed Cyclin D1 expression. The other prognostic parameters such as tumor size, grade and lymph node status did not show any association with Cyclin D 1 positivity.
Conclusions: Cyclin D1 expression was seen in 67.5% of ductal carcinoma and it showed a significant correlation with ER, PgR expression (92% in this study), which is in concordance with other similar studies in literature.