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A closer look at Lynch Syndrome

Last Modified: February 09, 2022


Lynch syndrome

This post was written by Breck Hunnicutt, NP, High Risk and Cancer Risk Reduction Clinic, Parkview Packnett Family Cancer Institute.

Lynch Syndrome is an inherited condition that increases the risk of various cancers, including colorectal cancer and endometrial cancer. Lynch Syndrome is also known as hereditary nonpolyposis colorectal cancer (HNPCC), and approximately 1 in 279 individuals in the United States have the gene mutation associated with it.


When changes occur in specific genes such as MLH1, MSH2, MSH6 or PMS2, Lynch Syndrome is present. Typically, these genes (mismatch repair genes) work together to repair genetic errors during cell division or DNA replication. However, if there is a change or mutation in one of these genes, this decreases the ability to repair the errors during cell division, leading to the growth of abnormal cells and possibly cancer.


Lynch Syndrome is inherited in an autosomal dominant pattern, meaning only one copy of an altered gene in the MLH1, MSH2, MSH6, and PMS2 is needed to cause this genetic condition. Every person has two copies of each gene, with one copy inherited from each parent. This means a person with Lynch Syndrome has a 50% chance of passing this gene mutation to each of their children. However, it’s important to note that not every person with Lynch Syndrome develops cancer. 

When to turn to genetic testing

Someone should consider genetic testing if there is a family history of colon cancer or endometrial cancer in family members younger than 50 years old. Other reasons to have genetic testing can include:

  • A relative with multiple Lynch-related cancers
  • Multiple relatives with Lynch-associated tumors
  • Family members diagnosed with cancer before the age of 50
  • More than one generation of the family is affected by a type of cancer

Genetic or tumor testing may also be warranted for the following reasons:

  • You were diagnosed with multiple Lynch-related cancers.
  • You were diagnosed with colorectal cancer or endometrial cancer before 50 years old.
  • Immunohistochemistry (IHC) testing determined the presence or absence of proteins. Missing proteins may tell doctors which mutated gene caused the cancer. This does not necessarily mean the individual has Lynch Syndrome but may indicate germline genetic testing is needed.
  • Microsatellite instability (MSI) testing indicates errors or instability in the DNA sequences in the tumor cells. If instability is present, this could mean germline testing is needed to determine if Lynch Syndrome is present.

A provider may also recommend genetic testing to help look for any changes in genes, which could provide information about the presence of Lynch Syndrome.

Cancers associated with Lynch Syndrome

Individuals with Lynch Syndrome have an increased chance of developing various cancers, including:

The cancer risk for those with Lynch Syndrome can vary. It depends on the specific mutation identified in the MLH1, MSH2, MSH6 or PMS2 genes. In the presence of Lynch Syndrome, the most significant risk of cancer due to any of the genes is colon and/or endometrial cancer.

Management of Lynch Syndrome

Individuals with Lynch Syndrome will receive a personalized screening and treatment plan tailored to their specific needs. The cancer screening plan could include:

  • Colon cancer screening. Providers utilize specialized techniques for colonoscopy to examine the entire colon. This could include high-definition colonoscopy, a narrow band colonoscopy or a chromoendoscopy. These techniques can increase the ability to detect difficult polyps, common in Lynch Syndrome. People with the syndrome typically begin colonoscopy screening at age 25 or earlier depending on their family history, then continue screening every 1-2 years.
  • Endometrial cancer screening. Women with Lynch syndrome should consider having an endometrial biopsy every 1-2 years and an annual pelvic exam with a transvaginal ultrasound depending on their menopause status.
  • Ovarian cancer screening. Women should consider an annual ultrasound and blood test to screen for ovarian cancer.
  • Urinary system cancer screening. An annual urinalysis can help detect blood or cancer cells.
  • Gastrointestinal cancer screening. An endoscopy can help screen for stomach and small intestine cancer.
  • Pancreatic cancer screening. An endoscopic ultrasound (EUS) or MRI/MRCP can help patients with at least one first or second degree relative with pancreatic cancer.
  • Aspirin for cancer prevention. A daily aspirin may be beneficial as recent studies have suggested a decrease in several cancers related to Lynch Syndrome. This recommendation is individualized based on the potential benefits and risks.
  • Surgery to prevent cancers caused by Lynch syndrome. Individuals with Lynch syndrome may consider surgery to reduce their risk of cancer. This could include the removal of the uterus and ovaries to prevent or reduce the risk of uterine and ovarian cancer. Providers base this decision on an individual’s desires and timing regarding childbearing.
  • Surgery to remove your colon (colectomy). Surgery to remove most or all of the colon may be a consideration to reduce or even eliminate the chance that colon cancer could develop. A colectomy may also be an option if colon polyps go unmanaged by colonoscopy.
  • Annual Skin surveillance. A yearly skin screening may help detect sebaceous neoplasms, a rare type of cancer that begins in an oil gland in your skin.
  • Annual physical and neurological exam.

For more information about Lynch Syndrome or if you are concerned about your risk factors, contact the Parkview Packnett Family Cancer Institute, or call the High Risk and Cancer Risk Reduction Clinic at 833-724-8326 to schedule an appointment.

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