IGF1 and neoplasm: Vitamin D has the number of confirmed anti-tumor functions, acting through VDR, such as inhibition of cell proliferation, accelerated apoptosis, regulation of the cell cycle and differentiation, among others thanks to the presence of FOXO protein, cyclin-dependent kinase inhibitors like p21 or p27, insulin-like growth factor (IGF), transforming growth factor beta (TGFβ), and Wnt-β/catenin24.