Updates in Colon Cancer Genetic Testing

In March of last year, I wrote a HealthConnect article called “4 Hereditary Colon Cancer Syndromes You Should Know” for Colorectal Cancer Awareness Month. In that article I discussed four of the more common hereditary colon cancer syndromes that we have been doing genetic testing for quite some time.

In this article, I’ll discuss some of the “newer” genes that are being offered as part of panel genetic testing related to colorectal cancer. Panels are simply broad genetic tests that are a cost-effective option to evaluate multiple genes at the same time.

GREM1

GREM1 is a newly described gene that is felt to cause Hereditary Mixed Polyposis syndrome (HMPS) that was originally identified in Ashkenazi Jewish families. HMPS is associated with multiple different kinds of colorectal polyps including: serrated polyps, hamartomatous polyps, juvenile polyps, and adenomatous polyps. People with HMPS are thought to be at an increased risk for colorectal cancer, but currently the risk is not well established. HMPS is thought to also be associated with colorectal polyps in adolescence.

POLD1 and POLE

POLD1 and POLE are two genes that are thought to be associated with some colon polyps, and an increased risk for colorectal, endometrial, and brain cancer. Cancer risk estimates are not clear yet for POLD1 and POLE, but it seems to be clearly tied to an increased risk for early onset colorectal cancer and/or multiple adenomatous colon polyps.

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In just the past year, the National Comprehensive Cancer Network (NCCN) has developed some medical management recommendations for those with gene mutations in GREM1, POLD1, and POLE. Although there are not clear risk estimates regarding the risk for colorectal cancer, the NCCN states that risk is presumed to be high from reports of families with these gene mutations. As research progresses, information will continue to develop for families with these mutations. Although there are no guidelines about when and who to test for these genes, many hereditary colon cancer gene panels are starting to include them.

If you or your family member has had negative genetic testing in the past due to personal/family history of colon cancer and/or colon polyps, you may want to consider re-visiting genetics to discuss these newly described genes in more detail.

If you have questions regarding genetic testing for hereditary colon cancer syndromes or genetic counseling, please call the ProMedica Cancer Institute’s Cancer Genetics Program at 419-824-5073.

Sarah AdelspergerSarah Adelsperger, MS, LCGC, is one of only two licensed and board-certified genetic counselors specializing in cancer in northwest Ohio and southeast Michigan. Sarah joined Kelly Morse, MS, LCGC, in the Cancer Genetics Program in May 2015 at ProMedica Cancer Institute.

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