Overview of Vitamin D Actions in Cancer

Throughout the last 2 or 3. decades it has become evident that vitamin D has effects beyond calcium and bone metabolism. A wide variety of cells and tissues are affected by vitamin D. These targets include tumor cells and the findings have led to a vast series of studies on the actions of vitamin D on cell growth regulation, treatment of cancer and development of potent synthetic vitamin D analogues as inhibitors of cancer cell growth. Various specialized chapters in this book will discuss in detail the effects of vitamin D on specific cancers. In this chapter our goal is to set the stage by providing an overview of the history and current state of knowledge of the field. We will address several areas: recent developments in studies of vitamin D and cancer, regulation of tumor cells, possible mechanisms, and clinical applications.