Identifying Patients at Risk for Lynch Syndrome and MAP

Finding patients at risk for Lynch syndrome and following up with them is perhaps the most critical step in potentially changing hereditary cancer outcomes. Although the MYH gene does not cause Lynch syndrome, patients with MYH-associated polyposis (MAP) can develop colorectal cancer even if they do not have a history of colon polyps. The following indicators in a patient’s personal or family history may indicate an increased risk for Lynch syndrome and help identify candidates for testing.

An individual with any of the following PERSONAL histories*:

  • Colorectal or endometrial cancer before age 50
  • MSI High histology before age 60:
    • Mucinous
    • Signet ring
    • Tumor infiltrating lymphocytes
    • Crohn’s-like lymphocytic reaction histology
    • Medullary growth pattern
  • Abnormal MSI/IHC tumor test result (Colorectal/Endometrial)
  • 2 or more Lynch syndrome cancers** at any age
  • Lynch syndrome cancer** with 1 or more relatives with a Lynch syndrome cancer**
  • A previously identified Lynch syndrome mutation in the family

An individual with any of the following FAMILY histories*:

  • A first or second degree relative with colorectal or endometrial cancer before age 50
  • Two or more relatives with a Lynch syndrome cancer**, one before the age of 50±
  • Three or more relatives with a Lynch syndrome cancer** at any age±
  • A previously identified Lynch syndrome mutation in the family

* Assessment criteria based on medical society guidelines. For these individual medical society guidelines, go to references

** Lynch-associated cancers include colon, endometrial, gastric, ovarian, ureter/renal pelvis, biliary tract, small bowel, pancreas, brain and sebaceous adenomas.

±Cancer history should be on the same side of the family