PTEN Gene Mutations (Cowden Syndrome)

What is PTEN and Cowden syndrome?

PTEN is a gene that helps repair damage to your DNA. People who are born with changes—called mutations—in the PTEN gene have a syndrome known as PTEN Hamartoma Tumor Syndrome (PHTS). PHTS may also be referred to as Cowden syndrome. People with an inherited PTEN mutation have an increased risk for several different types of cancer.   

Does everyone with an inherited PTEN mutation develop cancer?

Although the lifetime risk for cancer with a PTEN mutation is high, not everyone with the mutation develops cancer. Following the guidelines for screening and prevention increases the chances of preventing cancer or catching it at its earliest and most treatable stage.

My tumor has a PTEN mutation. Does that mean I have PHTS or Cowden syndrome?

No, testing positive for a PTEN mutation in your tumor does not necessarily mean you have PHTS or Cowden syndrome. 

PTEN mutations in tumors

Tumor testing (also known as biomarker testing) can look for different mutations within a cancer cell. Doctors order these tumor tests to make decisions about the best way to treat the cancer. Unlike normal cells, cancer cells often have many different types of mutations. Mutations that are only found within cancer cells are called acquired (somatic) mutations. PTEN is a common somatic mutation found in cancer cells. People with somatic PTEN mutations in their cancer cells do not develop PHTS or Cowden syndrome.  

Germline PTEN mutations

Most people who are born with PTEN mutations inherited the mutation from one of their parents. These people will have the mutation in every cell in their body. Mutations that are  inherited are called germline mutations. People with germline PTEN mutations have PHTS or Cowden syndrome. Genetic testing is used to test people for an inherited mutation in PTEN. 

De Novo PTEN mutations

Some people with PHTS did not inherit their PTEN mutation from either parent. This is known as a de novo mutation. De novo mutations happen to a person during development in the womb before they are born. People with de novo PTEN mutations may develop PHTS cancers, but depending on when the mutation happened during development, they may or may not have the mutation in every cell in their body. If the mutation is in their egg or sperm, they can pass the mutation on to their children. 

What are the signs of of an inherited PTEN mutation, PHTS or Cowden syndrome?

PHTS is complicated and not every family with a mutation will have all of the signs. It's important to speak with a genetics expert if you are concerned that PHTS may run in your family. Some of the signs that may indicate PHTS include one or more people in the family with:

• breast cancer, endometrial cancer or thyroid cancer. 
• many bengn growths in the gastrointestinal tract known as hamartomas. 
• multiple growths in the mouth or on the face. 
• spots of thickened skin on the hands or feet.
• a larger head size. 

This is not a complete list. FORCE recommends speaking with a genetic counselor who can help you make informed decisions about genetic testing. 

How do I find out if I have a PTEN mutation?

Genetic testing is a type of medical test that can help people learn if they have an inherited mutation in PTEN and other genes. The test can be performed on blood, saliva or tissue. The sample is collected and sent to a genetic testing lab. 

It's a good idea to speak with a genetics expert before having genetic testing. They will answer your questions about testing and ensure that the correct test is ordered. 

What are the cancer risks for people with a PTEN mutation?

People with an inherited mutation in PTEN have a high lifetime risk for different types of cancers, including:

• breast cancer
• endometrial cancer
• kidney cancer
• thyroid cancer
• colorectal cancer
• other cancers

The risks for cancer may begin at a young age.

What can people do if they have PHTS or Cowden syndrome?

If you test positive for a PTEN mutation, you have options. There are expert guidelines and clinical trials that focus on:

• cancer risks
• screening, early detection and risk-reduction
• cancer treatment

These guidelines are based on the most current research and updated yearly. People who test positive for a PTEN mutation should speak with a genetics expert to make sure that their medical care is based on the most up-to-date information. 

There may be other medical concerns for people with a PTEN mutation, including cancer risks for children beginning at a young age.

If you test positive for a PTEN mutation, you should inform your close blood relatives (first-, second-, and third-degree relatives) about your test results and encourage them to speak with a genetics expert.