Four scientific studies have confirmed that the presence of a gene variant called rs6983267- which is commonly associated with colorectal cancer- increases the risk of developing prostate cancer.

According to scientists the incidence of the gene’s variant in the investigated subjects is alarming, despite the overall insignificant influence it has over cancer risk. Researchers say carriers of this variant have about a 20 percent higher risk of developing a colorectal malignancy compared to non-carriers, but the fact that it has been found in half  of the subjects raises serious questions.

"In other words, it is very common in the general population," said Dr. Malcolm Dunlop, of Cancer Research UK and the University of Edinburgh, Scotland.

After sifting through data containing DNA of more than 1,800 people from a variety of racial and ethnic backgrounds, researchers from University of Southern California, Los Angeles, led by Christopher Haiman, found that the rs6983267 variant conferred about a 22 percent increase in colorectal cancer risk. Previous studies had already linked this gene variant to an increased risk for prostate cancer.

"This is the first common genetic risk factor that has been reproducibly associated with risks in multiple cancers," Haiman told reporters. "The association observed with this variant in both prostate and colorectal cancer provides very strong support for the hypothesis that there may be a common biological mechanism underlying cancer risk in this region of the genome."

In the United States, colorectal cancer it is the fourth most common cancer in men and women, and it is more common in people over 50, with the risk increasing with age.