AACR: Genetics May Explain Colorectal Cancer Disparities

Variation in MTHFR gene may protect some populations

THURSDAY, Nov. 29 (HealthDay News) -- Homozygosity for the variant T copy of the 5 10-methelenetetrahydrofolate reductase (MTHFR) gene, which regulates blood levels of folate, may help protect against the development of colorectal cancer in some populations but not in others, according to research presented at the American Association for Cancer Research conference on The Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved, held this week in Atlanta.

Mary A. Garza, Ph.D., of the Center for Minority Health in the University of Pittsburgh's Graduate School of Public Health, and colleagues conducted a pooled analysis of 26 studies involving more than 25,000 participants.

Overall, the researchers found that homozygosity for the T copy of MTHFR was associated with a 19 percent lower risk of colorectal cancer than homozygosity of the wild-type C copy. But they found that homozygosity for the T copy was only associated with a significantly reduced risk among Asians (31 percent). They also found that homozygosity for the T copy was associated with a statistically insignificant reduced risk of 8 percent in whites and statistically insignificant increased risks of 4 percent in blacks and 20 percent in Hispanics.

The researchers conclude that further investigation is needed to explain why the TT version appears to protect against colorectal cancer in Asians and possibly other groups, excluding Hispanics. "Normally, if one carries the recessive TT, which means reduced enzyme activity, you would expect a higher risk of developing colorectal cancer; however, the opposite is true," Garza said in a statement.

Abstract #A14

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