The Role of Vitamin D and Sunlight Incidence in Cancer

Background: Vitamin D (VD) deficiency affects individuals of different ages in many countries. VD deficiency may be related to several diseases, including cancer. Objective: This study aimed to review the relationship between VD deficiency and cancer. Methods: We describe the proteins involved in cancer pathogenesis and how those proteins can be influenced by VD deficiency. We also investigated a relationship between cancer death rate and solar radiation. Results: We found an increased bladder cancer, breast cancer, colon-rectum cancer, lung cancer, oesophagus cancer, oral cancer, ovary cancer, pancreas cancer, skin cancer and stomach cancer death rate in countries with low sunlight. It was also observed that amyloid precursor protein, ryanodine receptor, mammalian target of rapamycin complex 1, and receptor for advanced glycation end products are associated with a worse prognosis in cancer. While the Klotho protein and VD receptor are associated with a better prognosis in the disease. Nfr2 is associated with both worse and better prognosis in cancer. Conclusion: The literature suggests that VD deficiency might be involved in cancer progression. According to sunlight data, we can conclude that countries with low average sunlight have high cancers death rate. New studies involving transcriptional and genomic data in combination with VD measurement in long-term experiments are required to establish new relationships between VD and cancer.