Scientists searching for a pill to prevent cancer have found an exotic form of vitamin D that blocks formation of breast tumors in laboratory cell cultures. Rajendra G. Mehta of the University of Illinois (Chicago) said some other forms of vitamin D have been shown to combat cancer, but only at doses that are toxic to cells. Vitamin D-5, the compound made by his lab, blocks cancer formation at high concentrations without damaging the cells.
Mehta reported in the Feb. 5 Journal of the National Cancer Institute that a standard lab test used to screen compounds for anti-cancer action showed that vitamin D-5 linked with cells in the culture and prevented them from making changes that often lead to cancer. Cell cultures not protected by D-5 did develop precancer lesions when exposed to the chemicals. The compound is being tested on animals, and Mehta said early results are promising.