Stomach cancer can occur when genetic changes cause stomach cells to grow and divide abnormally. Some of these genetic changes have a high risk of passing from parent to child.

A child who inherits these changes has a heightened risk of developing stomach cancer. However, very few stomach cancers run in families.

On average, stomach cancer affects around 1.87% of males and 0.79% of females. However, various risk factors can increase these percentages.

The article discusses whether stomach cancer can run in families, other stomach cancer risk factors, and how people can prevent this condition.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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There are many different types of stomach cancer. Not all stomach cancers run in families.

According to a 2019 review, only around 1–3% of stomach cancers are hereditary.

Stomach cancer arises due to genetic changes in stomach cells. Some people acquire these changes spontaneously during their lifetime, and some people inherit them from their parents.

For stomach cancer to run in families, it must stem from a hereditary genetic change that increases the risk of stomach cancer.

An individual who inherits these changes acquires a genetic syndrome. The syndrome is a risk factor for stomach cancer.

There are many such heritable genetic syndromes, and they affect the risk of stomach cancer differently.

The following table looks at some genetic syndromes and the risk of developing stomach cancer.

Heritable genetic syndromeRisk of stomach cancer
hereditary diffuse gastric cancer syndrome (HDGC)up to 70%
Peutz-Jeghers syndromeup to 29%
juvenile polyposisup to 21%
Lynch syndromebetween 1% and 13%
Li-Fraumeni syndromebetween 1% and 4%
familial adenomatous polyposisgreater than 1%

People with these syndromes will not necessarily pass them on to their children. However, there is a risk that they will.

HDGC syndrome is an inherited cancer syndrome that increases the risk of developing gastric cancer. Various genetic changes can cause HDGC.

Mutations of the CDH1 gene are prominent HDGC-causing genetic changes. Parents with this mutation have a 50% chance of passing it on to their children.

As HDGC develops, it can cause digestive issues. Symptoms of HDGC include:

Having HDGC syndrome also increases the risk of a certain type of breast cancer, called lobular breast cancer, in females.

Anyone with symptoms of HDGC should seek a doctor’s advice.

Stomach cancer risk factors are things that make stomach cancer likelier to develop.

Aside from inherited genetic mutations, several things increase the risk of this condition.

Risk factors for stomach cancer include:

Some demographic factors, such as age and gender, are also relevant to stomach cancer risk.

This condition is more common in males and older individuals.

Ethnicity is another important demographic factor. In the United States, stomach cancer is least common among non-Hispanic white people.

It is impossible to completely eliminate all risks of stomach cancer.

However, some actions may help reduce the risk of developing stomach cancer. They include:

Doctors sometimes recommend more drastic preventive measures.

It is advisable for people with a family history of HDGC to have genetic testing.

If the tests show that someone has a CDH1 gene mutation, doctors may suggest complete surgical removal of the stomach because the risk of developing stomach cancer is so high. This is called a total gastrectomy.

Anyone with a CDH1 gene mutation should carefully consider the risks and benefits of this operation.

Although it could be life-saving, total gastrectomies can cause significant changes in how a person can eat. An individual’s doctor can advise them about the likely outcomes of their decision.

This section answers some common questions about stomach cancer and genetics.

Who is at highest risk for stomach cancer?

Stomach cancer is most common in older non-white men. Its risk factors include overweight, tobacco smoking, and alcohol drinking.

What is the main cause of stomach cancer?

It is not always possible to determine the cause of stomach cancer.

Changes in the DNA of stomach cells may be the main cause, but experts are still unsure how risk factors may affect this.

It is more common for people to acquire these genetic changes as they go through life. However, in a minority of cases, people can inherit these DNA changes.

What kind of stomach cancers are genetic?

HDGC — hereditary diffuse gastric cancer syndrome — is a cancer that stems from heritable genetic mutations.

Several genetic changes can cause stomach cells to grow into stomach cancer.

Most of these changes do not run in families. Stomach cancer has many nonhereditary risk factors, including alcohol consumption and low fiber diets.

A variety of health conditions can also increase someone’s risk of stomach cancer.

Some cancer-causing mutations can pass from parent to child. These include mutations of the CDH1 gene.

This genetic change can result in HDGC, a heritable form of stomach cancer. Generally speaking, the mutation greatly increases the probability of developing stomach cancer.

Avoiding some stomach cancer risk factors is possible. Doing so could help to prevent the condition.

However, certain risk factors make any preventive steps difficult. For instance, doctors sometimes recommend a total gastrectomy to people with CDH1 gene mutations.