Vitamin D probably does not protect against cancer, but reduces mortality. Daily intake in low doses between 400 and 4000 international units was decisive for the better chances of survival.
Vitamin D reactions in the body can probably inhibit tumor growth. People over 50 in particular should have their vitamin D level in their blood checked by their family doctor and to compensate for a possible deficiency. The German Cancer Research Center (DKFZ) employs more than 3000 people, making it Germany's largest biomedical research institution.