Genetic predisposition to gastric cancer.

Gastric cancer ranks as the third leading cause of cancer mortality worldwide and confers a 5-year survival of 20%. While most gastric cancers are sporadic, ~1%-3% can be attributed to inherited cancer predisposition syndromes. Germline E-cadherin/CDH1 mutations have been identified in families with an autosomal dominant inherited predisposition to diffuse gastric cancer. The cumulative risk of gastric cancer for CDH1 mutation carriers by age 80 years is reportedly 70% for men and 56% for women. Female mutation carriers also have an estimated 42% risk for developing lobular breast cancer by age 80 years. However, most individuals meeting clinical criteria for hereditary diffuse gastric cancer syndrome (HDGC) do not have a germline CDH1 mutation, and germline CDH1 mutation carriers do not all exhibit similar clinical outcomes in terms of age of diagnosis or cancer types. E-cadherin (CDH1) as the one known causative gene for HDGC accounts for only 40% of cases, leaving 60% with an unknown genetic diagnosis. In addition to HDGC, we will review other genetic syndromes with elevated gastric cancer risk, as well as newly implicated alterations in other genes (CTNNA1, DOT1L, FBXO24, PRSS1, MAP3K6, MSR1, and INSR) that may affect gastric cancer susceptibility and age-specific penetrance.