Vitamin D and colon cancer

Colon cancer is one of the most frequent and lethal neoplasias and the first to be associated with vitamin D deficiency. Many epidemiological studies indicate a protective effect of vitamin D on colon cancer. This is supported by preclinical studies using vitamin D, 1,25(OH)2D3 or analogues in cultured cells and experimental animals. These compounds regulate colon carcinoma cell gene expression, survival, differentiation, proliferation and invasion and inhibit angiogenesis and metastasis during colon cancer progression. Remarkably, in animal and in vitro models vitamin D compounds inhibit the Wnt/β-catenin signaling pathway, whose aberrant activation initiates and maintains colon cancer. Moreover, recent data show that 1,25(OH)2D3 protects against colon cancer acting also on tumor stromal fibroblasts. However, clinical data are scarce and inconclusive, and a definitive answer about the role of vitamin D compounds in the prevention and treatment of colon cancer requires new, large, well-designed clinical trials.Peer reviewe