Colorectal Cancer Awareness Month: Understanding Lynch Syndrome

Public interest in high risk hereditary cancer conditions is on the rise. We’ve seen firsthand how increased awareness of Hereditary Breast and Ovarian Cancer (HBOC) has led to more individuals being identified with BRCA1 and BRCA2 gene mutations. Recent studies have suggested that up to 95% of women with young onset breast cancer (<40 years) are pursuing genetic testing as part of their treatment decision-making (S Rosenberg JAMA Oncology, 2016). This is crucial given the known benefits of increased surveillance and other risk-reduction strategies. People with BRCA mutations are no longer living despite carrying mutations; they are living with these mutations.

Widespread public awareness of life-saving medical information is always the end goal for those in the medical community, and increased public interest in the interaction between genetics and personal health is just what genetic counselors like myself hope for. With that being said, and given that March is Colorectal Cancer Awareness Month, it might be time for another hereditary cancer syndrome to take some time in the spotlight. Enter center stage: Lynch syndrome.

Lynch syndrome is the most common hereditary colon cancer syndrome. Lynch syndrome is characterized by a significant risk of colon cancer and endometrial cancer as well as increased risks of a number of other cancers, such as ovarian cancer and other GI related cancers (stomach, pancreatic cancer, urinary tract, small intestine, etc.). The genetics community is trying to spread the word that “reproductive cancers” aren’t just related to the BRCA genes, and here’s a perfect example why. It has been estimated that 3% of all colon cancers and 2% of endometrial cancers are caused by Lynch syndrome. In other words, sometimes that random appearing collection of malignancies may not be random after all. It could be Lynch syndrome.

Lynch syndrome is caused by mutations in one of five genes: EPCAM, MLH1, MSH2, MSH6 and PMS2. Collectively, these genes are called mismatch repair genes. The mismatch repair pathway is important for maintaining genomic stability and therefore, if a mutation is present in one of these genes, genetic damage can accumulate at faster than normal rates causing a higher risk of cancer.

Thankfully, like being found to carry a BRCA mutation, individuals with Lynch syndrome can have increased surveillance beginning at younger ages and sometimes risk-reducing surgery too. While screening of the GI tract may not sound (or be) pleasant, it beats being diagnosed with cancer.

Nationwide we recognize Colorectal Cancer Awareness Month in March by wearing blue and promoting screening, diagnosis and prevention. And on March 22nd, we acknowledge Lynch Syndrome Awareness Day by increasing awareness of hereditary cancer syndromes. If you are interested in learning if you are at risk for Lynch syndrome or another cancer susceptibility condition, please contact Insight Medical Genetics at 312-981-4400.