High Expression of Cyclin D1 is an Independent Marker for Favorable Prognosis in Middle Eastern Breast Cancer

Abstract Cyclin D1 protein regulates cell cycle progression which is mediated by its interactions with cyclin-dependent kinases. Over-expression of Cyclin D1 has been observed in several human cancers. This study was conducted to evaluate Cyclin D1 expression in a large cohort of Middle Eastern breast cancers and determine its prognostic significance. Cyclin D1 expression was assessed immunohistochemically and its association with clinico-pathological parameters was analyzed. Cyclin D1 was over-expressed in 59.4% (596/1003) of cases and significantly associated with a subset of breast cancers having favorable prognostic features such as low grade (p < 0.0001), low stage (p = 0.0276), estrogen receptor positive (p < 0.0001) and progesterone receptor positive (p < 0.0001) tumors. An inverse association was found with triple negative breast cancers (p < 0.0001). More importantly, Cyclin D1 expression was an independent predictor of favorable overall survival in our cohort (Hazard ratio = 0.69; 955 confidence interval = 0.48 - 0.98; p = 0.0405). Also, tumors that highly expressed cyclin D1 had a longer recurrence free survival. However, recurrence free survival was only significant in univariate analysis. In conclusion, our results reinforced the role of cyclin D1 in breast cancer pathology and revealed its expression as a valuable independent prognostic indicator for breast cancer from Middle Eastern ethnicity. Citation Format: Khawla S. Al-Kuraya, Abdul K. Siraj, Sandeep K. Parvathareddy, Sarah Siraj, Saud Azam, Padmanaban Annaiyappanaidu, Maria Angelita Sabido, Mark Ranier Diaz. High expression of Cyclin D1 is an independent marker for favorable prognosis in Middle Eastern breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1963.