Background: Cyclin D1 has a central role in cell cycle control, but also directly affects the estrogen receptor. It has been shown that cyclin D can activate the estrogen receptor in a ligand-independent way and studies are implying that cyclin D overexpression may be linked to tamoxifen resistance. We wanted to explore the prognostic value of cyclin D overexpression in node negative breast cancer.

Patients and methods: We examined the expression of cyclin D1 using immunohistochemistry on tissue micro array (TMA) sections from a case control study (1:1) consisting of 380 patients with T1-2N0M0 breast cancer. Adjuvant radiotherapy and endocrine treatment was allowed, but not chemotherapy. Event was defined as breast cancer death. Breast cancer specific survival was analyzed in univariate and multivariate models using conditional logistic regression.

Results: Cyclin D1 was inversely correlated to Elston grade (rho = 0.2; p = 0.000); moderately correlated to PgR status (rho = 0.3, p = 0.000) and strongly correlated to ER status (rho = 0.4, p = 0.000). Cyclin D1 overexpression did not increase the risk for breast cancer death analyzing the whole patient population. However, subgroup analyses of hormone receptor positive patients showed an increased risk for breast cancer death (OR 4.2; 95% CI 1.4-12.6) and (OR 3.9; 95% CI 1.3-12) when adjusted for tumor size and age at diagnosis.Conclusion: Cyclin D1 is an independant prognostic factor of outcome in hormone receptor positive and node negative breast cancer with overexpression increasing the risk for breast cancer death 4-fold.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-02-02.