TP53 Gene

February 13, 2026

This page was reviewed under our medical and editorial policy by Heather Hampel, M.S., C.G.C., professor, Department of Medical Oncology & Therapeutics Research, City of Hope^® Cancer Center Duarte.

Everyone has the TP53 gene, which stands for tumor protein p53. The TP53 gene plays an important role in helping the body stop tumors from growing (tumor suppression) and in fixing damaged DNA within cells (DNA repair). DNA is a molecule found in all cells and carries the instructions for how each cell develops and functions.

This guide to the TP53 gene and its role in cancer risk is designed to help patients find out more.

What Is a TP53 Mutation?

A TP53 mutation is a harmful change in the DNA sequence, or the order of chemical building blocks inside this gene. When these changes occur, they may change the way cells develop and increase a patient’s risk for developing cancer.

The TP53 gene makes a key protein called p53. When cells are damaged by things like ultraviolet (UV) radiation from the sun or chemicals, the p53 protein helps to either repair the cell’s DNA damage, making it a healthy cell again, or instruct the damaged cell to die off so that the abnormal cell does not multiply. If the TP53 gene is not working normally to make p53, damaged cells may stick around and divide and multiply, creating a tumor growth.

These mutations are linked to an increased cancer risk, and they are quite common.

When TP53 mutations occur, they are either inherited, meaning they are passed down from the genetics of a person’s parents, or acquired. Acquired (somatic) mutations are gene changes that occur within a person’s lifetime. Acquired TP53 mutations are common; they are found in more than 50% of all cancers, according to the U.S. National Library of Medicine (NLM).

Inherited TP53 mutations are rare and cause Li-Fraumeni syndrome, a rare disease that increases the risk for developing several cancer types, such as breast, bone and soft tissue sarcomas, lung cancer, leukemia, and adrenocortical carcinoma. It is found in 1 of every 5,000 to 20,000 people, according to NLM.

TP53 Gene Mutation and Cancer Risk

The TP53 gene is linked to an increased risk of several cancer types, including the following.

Lung cancer: About 50% of lung cancers contain acquired TP53 mutations. They are most common in small cell lung cancers.

Breast cancer: Acquired TP53 mutations are found in 20% to 40% of all breast cancers. They also tend to be more aggressive than breast cancers without the mutation. Inherited mutations are also linked to breast cancer, but they are less common.

Cholangiocarcinoma: This type of cancer begins in the bile ducts. It is linked to acquired TP53 gene mutations.

Bladder cancer: TP53 mutations are found in about 50% of nonmuscle invasive bladder cancers.

Ovarian cancer: Acquired TP53 mutations are found in nearly 50% of all ovarian cancer cases.

Melanoma: This type of skin cancer is linked to acquired TP53 mutations, and it has an inherited genetic link in a small percentage of cases.

Head and neck squamous cell carcinoma: Roughly 50% of these cancers have acquired TP53 mutations.

Wilms tumor: This is a type of kidney cancer that affects children. It is linked to TP53 mutations.

It may help patients with known TP53 mutations to discuss the ways they may reduce their cancer risk with their doctor. Increased cancer screening tests may be recommended to catch anything early, when it may be more treatable.

Family members of patients with inherited TP53 mutations or a history of breast, bone and muscle cancers may consider undergoing genetic testing themselves to understand their risk for developing cancer.

Who Is a Candidate for TP53 Genetic Testing?

There are two different kinds of genetic testing:

• Genetic testing for inherited TP53 gene mutations may be ordered by a genetic counselor and performed on blood, saliva or skin samples. This type of testing is performed to see if a patient has an inherited cancer syndrome.
• Tumor genomic testing for acquired TP53 and other gene mutations may be ordered by an oncologist and performed on a tumor sample or circulating tumor cells in the blood. This type of testing is performed to look for the acquired gene mutations that caused the tumor to develop, because this can sometimes give the care team options for targeted therapies.

Patients may discuss both types of genetic testing with their doctor to decide if it may be appropriate for them. Patients may be referred to a genetic counselor for hereditary cancer genetic testing to help weigh the pros and cons of testing and what the information may mean so that patients are comfortable and empowered with the information.

Tumor genomic testing always includes the TP53 gene and may be recommended for any patient with cancer.

Hereditary gene testing may be performed for several types of patients.

Patients already diagnosed with cancer: Understanding a cancer’s genetics may help doctors create a personalized treatment plan for the patient’s cancer type.

Patients with an increased risk of Li-Fraumeni syndrome: Individuals with close family members who have had cancer associated with this syndrome may benefit from testing. Cancers closely linked to Li-Fraumeni syndrome include:

• Brain tumors
• Breast cancer
• Acute leukemia
• Certain bone and soft tissue cancers
• Adrenal gland cancer

Cost of TP53 Gene Testing

For hereditary cancer genetic testing, in most cases a multi-gene panel test will be ordered. This type of test checks several genes at the same time and may be useful when a family has no known gene mutations. Some of the genes that are typically included in multi-gene panel tests for breast and other cancers are TP53, BRCA1, BRCA2, ATM, CHEK2, CDH1, PTEN and PALB2.

Multi-gene panel testing for TP53 mutations may be covered by health insurance if the patient meets testing criteria and it is recommended by a patient’s doctor. However, patients should contact their insurance provider to find out more.

As an alternative, patients may wish to pay out of pocket for TP53 testing. Self-pay costs vary, depending on the laboratory, but typically range from $250 to $400.

For tumor genomic testing, which always includes TP53 and many other genes, costs may be higher but the test is often covered by insurance if it is recommended by a patient’s doctor and may affect the treatment plan. These laboratories also often have financial assistance programs that may help reduce or eliminate the out-of-pocket costs for patients.

TP53 Test Results

After TP53 testing, results may be ready in about two to three weeks, but this may vary. Once test results are ready, they are discussed with the patient.

A positive test: This means a TP53 mutation (harmful genetic change) linked to an increased risk of breast, sarcoma, lung, leukemia, adrenocortical and other cancers was found. For patients testing positive, additional screening, risk-reducing surgeries, and preventive lifestyle changes may be recommended.

A negative test: This result is especially helpful in families with a known TP53 genetic mutation because it means the person tested did not inherit it. This result is known as a true negative. It means the person’s cancer risk is about the same as that of the general population. When a person has a strong family history of cancer but has no associated gene mutation, the negative result is known as an uninformative negative. This means a genetic mutation may be still involved, but it was not detected by current technology. Doctors may recommend further testing or check-ups as new technology becomes available.

An inconclusive result: A genetic change was found, but there is not yet enough information to know whether it increases cancer risk. This type of genetic change is referred to as a variant of uncertain significance (VUS). People with this finding are urged to stay in touch with their provider in case new information becomes available about their variant over time.

Sometimes TP53 gene mutations are found at a lower proportion than expected on a blood or saliva test. In these cases, additional testing using a skin sample may be required to determine if the patient really has Li Fraumeni syndrome.

Not all gene variations, or mutations, have been studied. Meeting with a genetic counselor to go over the pros and cons of testing may help patients understand the limitations of each test.