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Lynch Syndrome

What is Lynch Syndrome?

Lynch syndrome is the most common form of hereditary colorectal cancer. People with Lynch syndrome have an increased risk of developing colon cancer as well as cancers of the digestive tract, gynaecologic tract, and other organs. If one person in the family has Lynch syndrome, their close relatives may also have it.

Is my family at risk for Lynch syndrome?

Colorectal cancer is a common cancer. In Singapore, it is the most frequent cancer in males and the second most frequent cancer among women. However, most colorectal cancer is not hereditary.

The history of cancer in your close relatives is a clue to the risk of Lynch syndrome in your family. Close relatives include: children, brothers and sisters, parents, aunts, uncles, grandchildren and grandparents on one side of the family. A history of cancer in cousins and more distant relatives may also be important.

Lynch syndrome cancers include colorectal, endometrial, ovarian, stomach, small bowel, pancreatic, kidney, hepatobiliary, ureter, or brain cancer as well as certain skin tumors.

Lynch syndrome is more likely if one or more of the following features can be confirmed in your family:

  • A person with colorectal cancer at age 50 or younger.
  • A person with colorectal cancer and another Lynch syndrome cancer with one diagnosed at age 50 or younger.
  • Two close family members with a Lynch syndrome cancer at age 50 or younger.
  • Three close family members (across generations) with a Lynch syndrome cancer, including at least one case of colorectal cancer AND at least one cancer diagnosed at age 50 or younger.
  • Indicative immunohistochemistry (IHC) or microsatellite instability (MSI) results on tumor tissues.

How is Lynch syndrome diagnosed?

MSI and IHC are screening tests that can be performed on tumor (cancer) tissue to determine if Lynch syndrome is likely.

Definitive test for Lynch syndrome – Genetic testing

Lynch syndrome genetic testing is a blood test available through the service Genetic testing is complex, thus, individuals interested in testing will undergo genetic counselling to better understand the condition within the family, their personalised cancer risk and the implications of the genetic test.

If your family history of cancer is suggestive of Lynch syndrome, please talk to your doctor. A referral to the CGS can help you find out more about Lynch syndrome and genetic testing.

Download the English brochure.

Download the Chinese brochure.