White males who have the "tanning gene" may be at a higher risk of prostate cancer.
About 80 percent of all men have this gene, which is important for skin tanning, a National Institute of Environmental and Health Sciences news release reported.
The team suggested that variations in a gene pathway associated with a tumor-blocking gene, called P53, could either help or hurt a patient health wise.
"Gene variations occur naturally, and may become common in a population if they convey a health benefit," Douglas Bell, Ph.D., author on the paper and researcher at the National Institute of Environmental Health Sciences (NIEHS), part of NIH, said. "It appears that this particular variant could help protect light-skinned individuals from UV skin damage, like burning or cancer, by promoting the tanning process, but it permits testicular stem cells to grow in the presence of DNA damage, when they are supposed to stop growing."
The team gathered data from the " intersection of more than 20,000 p53 binding sites in the human genome, 10 million inherited genetic variations genotyped in the 1000 Genomes Project, and 62,000 genetic variations associated with human cancers identified in genome-wide association studies (GWAS). "
Thousands of international researchers helped analyze the massive data set.
"In the end, one variant in the p53 pathway was strongly associated with testicular cancer, but also, surprisingly, displayed a positive benefit that is probably related to tanning that has occurred as humans evolved," Xuting Wang, Ph.D., of NIEHS, co-author and lead bioinformatics scientist on the paper, who led the data hunt, said.
The team conducted difficult lab procedures to confirm the link between the variant, cancer, and tanning.
"White males with a single nucleotide variation in KITLG, called the G allele, have the highest odds of having testicular cancer. In fact, the twofold to threefold increased risk is one of the highest and most significant among all cancer GWAS conducted within the past few years," said Bond. "The high frequency of this allele in light skin individuals may explain why testicular cancer is so much more frequent in people of European descent than those of African descent," Gareth Bond, Ph.D, a researcher from who conducted the molecular experiments, said.
Bond believes this can help explain why testicular cancer responds so well to chemotherapy treatments.
"Most other tumors have a mutant p53, but in these testicular cell tumors, the p53 is functioning properly, and the drugs used for testicular cancer appear to work in concert with p53's tumor suppression function to kill the cancer cells," Bond said.
