Gene variants accounting for some of the differences between men in their risk of developing testis cancer have been identified according to two studies published online this week in Nature Genetics.

Testicular germ cell tumor is the most common malignancy in men between the ages of 15 and 45 years and is five times more common in men of European ancestry than in those of African ancestry. To find gene variants associated with risk of this disease, Michael Stratton, Katherine Nathanson and colleagues examined thousands of men of European ancestry in the UK and US.

One of the risk-associated genes they found -- KITLG -- also confers differences in skin and hair color. Since KITLG risk variants are more common in populations with recent European origins than in those with recent African origins, these genetic differences may explain some of the population differences in the incidence of the disease.