Genome offers clues to esophageal cancer disparity

https://www.eurekalert.org/pub_releases/2018-12/mm-u-goc122018.php

Public Release: 20-Dec-2018
Michigan Medicine - University of Michigan

A genomic duplication may help explain why esophageal adenocarcinoma is much more common in Caucasians and presents a potential target for prevention

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Researchers found Caucasians have a duplication on a portion of the genome that appears to reduce the expression of GSTT2. This enzyme protects cells against oxidative damage, such as the type caused by reflux, a key risk factor for esophageal adenocarcinoma.

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"The risk factors for esophageal cancer such as obesity and reflux happen at the same rate for African-Americans and Caucasians. But African-Americans are not getting cancer," Beer says. "We see the highest risk of cancer in people who have this genomic duplication plus obesity. It's not just the presence of the duplication but these other factors contributing to the damage."

Rates of esophageal adenocarcinoma have increased 600 percent over the last three decades, caused by a rise in obesity and gastroesophageal reflux disease, or GERD. The other type of esophageal cancer, squamous cell carcinoma, is more frequently seen in African-Americans.

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Next, they used a cranberry proanthocyanidin extract and found it reduced levels of DNA damage in the esophagi of rats exposed to reflux. This suggests potential for preventing esophageal adenocarcinoma.

"They key with esophageal cancer is to prevent it. Many people don't know they have the disease until it's too late to treat it effectively," Beer says.

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