April 1, 2009

• Protein variant tied to colon cancer in African-Americans

• Adds new detail to push for personalized medicine

BIRMINGHAM, Ala. - A new study reveals the first-ever genetic link to the reason African-Americans are at increased risk of dying from colon cancer.

The discovery by researchers at the University of Alabama at Birmingham (UAB) is focused on a protein variant called Pro72 identified through genetic testing. In the study, African-Americans with a Pro72 protein variant had more than double the risk of dying from an advanced form of colon cancer compared to whites, the researchers said.

The discovery boosts the scientific understanding of racial disparities in cancer and other diseases and adds new detail in the ongoing search for more personalized cancer-fighting therapies, said Upender Manne, Ph.D., an associate professor in the UAB Department of Pathology who led the study.

The findings are published in the April 1 issue of the journal Clinical Cancer Research.

Racial Disparity Link

Pro72 is a molecule that arises from alterations in a tumor suppressor gene called p53, a gene that has been linked to half of all cancers in the world.

"This paper shows that in a subset of patients with the Pro72 variant, the susceptibility to disruptive p53 alterations may be a possible molecular explanation for the racial disparity," said Manne, an associate scientist in the UAB Comprehensive Cancer Center.

The study included DNA analysis of 373 colorectal tumors. Researchers first sequenced the whole p53 gene in the tumors, and then analyzed the Pro72 frequency. Seventeen percent of African-Americans have a Pro72 variant, whereas only 7 percent of whites have the variant, Manne said.

UAB conducts community-based research and is a national leader in colorectal cancer prevention through its Minority Health & Health Disparities Research Center and treatment at the UAB Comprehensive Cancer Center.