Current knowledge on the active form of Vitamin D synthesized in the skin and its effects on malignant melanoma.

The link between sunlight and skin cancer is a frequently discussed topic. However, ultraviolet radiation also induces the production of Vitamin D in the body. Keratinocytes and their ability to synthesize the active form of Vitamin D, which is consumed at the place of its origin in the skin, have a unique place in this discussion. We observe a remarkable sunshine-related paradox when we monitor the relationship between the dose of solar radiation and one type of skin cancer - malignant melanoma. Recent knowledge of the non-calcemic effects of Vitamin D, which include growth regulation, DNA repair, differentiation, apoptosis, membrane transport, metabolism, cell adhesion and oxidative stress, could help to further clarify this relationship. In this context, adjuvant Vitamin D therapy is currently being considered in patients with malignant melanoma, and this is expected to reduce tumor invasiveness and micrometastases and thus improve patient prognosis and reduce the risk of relapse.