Abstract: The traditional role of vitamin D is to regulate calcium and bone metabolism.However,there is increasing evidence that vitamin D is closely related to the occurrence and development of malignant tumors.It has been found that low vitamin D levels are associated with increased risk of breast,colon,and prostate cancers.Although randomized controlled trials in the human body have not been able to determine the beneficial effects of vitamin D on cancer,some studies have shown that vitamin D deficiency increases the risk of cancer.Avoiding deficiency and adding vitamin D supplements may be an economical and safe way to reduce the incidence of cancer and improve the prognosis of cancer.This article focuses on the role and research progress of vitamin D in digestive system tumors,and explores its possible mechanism of action.

Key words: Digestive system tumors, Vitamin D, Vitamin D receptors, Review