Genes May Explain Role of Race in Colon Cancer Risk

Genes May Explain Role of Race in Colon Cancer Risk
WEDNESDAY, Nov. 28 (HealthDay News) -- Genes may contribute todisparities in colorectal cancer rates between ethnic and racial groups, anew U.S. review suggests.
The research team, led by investigators at the University ofPittsburgh, analyzed 26 studies that included more than 25,000 people.
They found that people who have two "T" copies of the MTHFR gene thatmetabolizes folate -- a chemical needed to produce and maintain newcells -- are 19 percent less likely to develop colorectal cancer thanpeople with two "C" copies of the gene.
When they looked at specific racial/ethnic groups, the reviewers foundthat the risk of colorectal cancer in people with the two "T" copies,compared to those with the two "C" copies, was 31 percent less in Asians,8 percent less in whites, and 4 percent less in black Americans.
They also found that Hispanics who had one "T" copy and one "C" copy ofthe gene were 20 percent more likely to develop colorectal cancer thanHispanics with two "C" copies of the gene. However, the researchers saidthis finding was not statistically significant.
The results of the analysis were to be presented Wednesday at theAmerican Association for Cancer Research's conference on The Science ofCancer Health Disparities in Racial/Ethnic Minorities and the MedicallyUnderserved, in Atlanta.
The study shows that two copies of the "T" version of the gene "may beprotective in different degrees against colorectal cancer in somepopulations but not in others," lead investigator Mary A. Garza, deputydirector of the Center for Minority Health in the University ofPittsburgh's Graduate School of Public Health, said in a preparedstatement.
The finding that two "T" copies of the MTHFR gene may help protectagainst colorectal cancer in certain racial/ethnic groups warrants furtherstudy, she said.
This is the first pooled analysis to examine the association betweenspecific genes and the risk of developing colorectal cancer inracial/ethnic groups, according to Garza.
"We are trying to unlock the role genetics, through gene-environmentinteractions, may play in understanding the underlying causes of healthdisparities," she said.
Overall, colorectal cancer death rates in the United States have beendeclining, but blacks and other minorities account for a disproportionateshare of colorectal cancer patients.
"This disparity exists even after accounting for various environmentaland social factors, so it makes sense that genetics could play acontributing role in this cancer disparity," Garza said.
More information
The U.S. National Cancer Institute has more about colorectal cancer risk.