Stomach cancer usually develops without a known underlying cause, but in some cases, it’s linked to certain genes passed through families.

Stomach cancer makes up about 1.5% of cancer diagnoses in the United States each year.

Research estimates that 1% to 3% of people with stomach cancer have a hereditary form caused by inherited genes. Additionally, about 10% of stomach cancers cluster in families.

In this article, we take a look at types of stomach cancer caused by inherited genes, stomach cancer risk factors, and prevention strategies.

Most people with stomach cancer don’t have a family history of it. Certain gene mutations can cause family cancer syndromes, such as Lynch syndrome or hereditary diffuse gastric cancer, that increase your risk of stomach cancer and other cancers.

A family cancer syndrome is a higher than normal risk of developing cancer due to certain genes passed from your parents.

Hereditary diffuse gastric cancer

According to a 2020 review, less than 3% of stomach cancers are caused by a family cancer syndrome called hereditary diffuse gastric cancer. About 40% of people with this syndrome have identified mutations associated with cancer in their CDH1 gene.

Men with hereditary diffuse gastric cancer have up to a 70% chance of developing stomach cancer before age 80, and women have as high as a 56% chance.

If one of your parents has hereditary diffuse gastric cancer, you have a 50% chance of having it too.

Other family cancer syndromes

Gene mutations have also been linked to other family cancer syndromes that increase your risk of stomach cancer.

Variants of the following genes are associated with an increased risk of stomach cancer:

GeneSyndromeRisk of developing stomach cancerOther cancers at increased risk
CDH1hereditary diffuse gastric cancer syndromeup to 70%lobular breast cancer
STK11Peutz-Jeghers syndromeup to 29%• gastrointestinal (GI) cancer
pancreatic cancer
breast cancer
SMAD4juvenile polyposisup to 21%GI cancer
APC promoter 1Bgastric adenocarcinoma and proximal polyposis of the stomach12%–20%GI cancer in some families
MLH1, MSH2, MSH6, PMS2Lynch syndrome1%–13%• GI cancer
ovarian cancer
uterine cancer
urinary tract cancer
APCfamilial adenomatous polyposisless than 1%GI cancer, thyroid cancer
TP53Li-Fraumeni syndrome1%–4%• breast cancer
brain cancer
• lung cancer
adrenal cortical cancer

When the cause of stomach cancer isn’t known, the cancer is referred to as “sporadic cancer.” Most stomach cancers are sporadic.

The four most common types of stomach cancer are:

  • Adenocarcinoma: About 90% to 95% of stomach cancers are classified as adenocarcinoma. Most of these cancers aren’t linked to a family history, except for cancers caused by family cancer syndromes.
  • Gastrointestinal (GI) stromal tumors: GI stromal tumors usually have no clear cause. In rare cases, they’ve been found in several members of the same family.
  • Neuroendocrine tumors: The vast majority of neuroendocrine tumors in the GI tract are not hereditary. About 10% of GI tract neuroendocrine tumors are associated with a hereditary syndrome called multiple endocrine neoplasia type 1.
  • Lymphomas: The two most common types of lymphoma that develop in your stomach are called mucosa-associated lymphoid tissue gastric lymphoma and diffuse large B-cell lymphoma. Neither type has been linked to family history.

In a 2022 review of studies, researchers identified the following risk factors for stomach cancer:

Risk factorPercentage your risk is increased by
H. pylori infection280%–480%
being male95%
family history50%–250%
moderate or high salt intake41%–68%
heavy alcohol intake20%–65%
type A blood11%–21%

Other risk factors that have been identified for stomach cancer include:

  • increasing age
  • ethnicity, with the highest risk in:
    • Hispanic Americans
    • African Americans
    • Native Americans
    • Asian Americans and Pacific Islanders
  • geography, with stomach cancer being most common in:
    • East Asia
    • Eastern Europe
    • South and Central America
  • overweight or obesity
  • a diet high in preserved foods
  • a diet low in fruits or vegetables
  • previous stomach surgery
  • some types of stomach polyps
  • pernicious anemia
  • Ménétrier disease, a condition characterized by the overgrowth of the mucous membranes inside your stomach

You can’t always prevent stomach cancer, but there are many habits you can adopt to minimize your risk. Habits that might help include:

Most cases of stomach cancer are not linked to family history. Less than 3% of stomach cancers are thought to be directly linked to genes inherited from your parents, and less than 10% of stomach cancers seem to cluster in families.

Some top risk factors for stomach cancer include H. pylori infection, being male, and smoking.

Avoiding smoking, maintaining a moderate body weight, and eating a nutritious, balanced diet are among the ways you can minimize your risk of developing stomach cancer.