Vitamin D plays a very important role in maintaining the proper functioning of our body, and its deficiency not only causes disorders of the skeletal system, but also contributes to the development of a number of lifestyle diseases, including cancer. The team of Prof. Michał Żmijewski from the Department of Histology of Medical University of Gdańsk is involved in research on the causes and effects of vitamin D deficiency and the use of vitamin D and its analogues in the treatment of cancer and skin diseases. In this context, the study of molecular mechanisms underlying the action of vitamin D and its interaction with other drugs seems particularly interesting.