Scientists in Britain said they have found the first genes that are associated with testicular cancer, the commonest form of cancer for men between age of 15 to 45. Telltale variants in chromosomes 5, 6 and 12 are linked to the increased risk of the disease, according to their study, which compared the genetic code of 730 men who had testicular cancer with those of healthy men. Inheriting the basket of three factors boosts the risk of this cancer, called testicular gem cell tumour, by up to fourfold. The study is published online in the journal Nature Genetics. "We have known for some time that men whose father or brothers have had testicular cancer are likely to get it themselves. We have been searching for this genetic link," said one of the investigators, Elizabeth Rapley of the Institute of Cancer Research, in the southern English county of Surrey. "We believe there are more (risk factors) still to be found and we are working on identifying the rest." The three telltales lie near genes that nurture testicular cells which are precursors in sperm development. Worldwide, the incidence of testicular cancer is 7.5 cases per 100,000 men, but the rates vary remarkably between countries and also according to ancestry, the ICR said in a press release.