Dual Roles of Cyclin D1 in Normal Physiology and Disease

The rate of division and proliferation of a cell is determined by a complex sequential process known as the cell cycle. This process is directed by a family of numerous regulatory proteins known as cyclins, which are expressed at various phases of the cell cycle. Among the different cyclins, cyclin D1 is one such important cell cycle nucleoprotein that regulates the rate of mitotic division as well as many other biological mechanisms. In the recent years, however, cyclin D1 has shown abnormal expression within the cell cycle machinery and has been overexpressed in a wide variety of tumors, therefore implying that it might have an influence in the cell cycle aberration and can initiate oncogenesis. Hence, the emergence of cyclin D1 expression in cancer has indicated its significance as a tumor biomarker. In addition, cyclin D1 has also raised questions regarding its molecular role in many other pathologies apart from cancer as well, and so till date, it continues to be a topic of interest.