Is Cancer Genetic?

Learn about the impact of your genes on cancer risk

Grandmother with cancer holds grandchild or great-grandchild

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Cancer is caused by genetic changes that trigger cells to grow out of control, but it is not usually hereditary. Cancer-causing genetic mutations in segments of DNA can be inherited or, more commonly, acquired over time.

Inherited gene mutations are passed from parents’ reproductive cells (the egg or sperm) to their offspring—and are present in all body cells of the offspring. Acquired genetic mutations, on the other hand, originate in one cell due to things like cell division errors or exposure to carcinogens (cancer-causing substances), like tobacco or radiation.

Most cancers are multifactorial, which means your risk goes up depending on a variety of factors including your genetics, environment, lifestyle, and personal health history. Learn more about cancer genetics and how gene mutations may cause cancer

Hereditary Cancer Syndrome 

So, is cancer genetic? In about 5% to 10% of cases, inherited genetic mutations are indeed at the root of increased cancer risk. These are known as hereditary cancer syndromes or germline mutations. 

Sometimes, cancer can appear to “run in your family” when in fact a lifestyle or environmental factor that's shared by family members may be the culprit, such as a smoking habit.

Certain signs in your family’s medical history may indicate that you have inherited cancer risk. These include:

  • Cancer in many generations (like a grandmother, mother, and daughter)
  • Multiple cases of the same type of cancer, especially if it is uncommon or rare 
  • Cancer at younger ages than usual
  • Childhood cancer in siblings
  • More than one type of cancer in a single person
  • Cancer in a pair of organs (such as both eyes, breasts, or kidneys)
  • Cancer in the sex typically not affected (like male breast cancer)

The concern is particularly high if you notice a pattern of cancer in your immediate family or on one side of your family. In this case, many healthcare providers recommend genetic testing to rule out other causes, identify a hereditary cancer syndrome, and better guide your medical decisions in the future. 

Types of Inherited Cancers 

An inherited gene mutation doesn’t guarantee that you’ll develop cancer, but it means that you’re at an increased risk of developing the disease. 

Here are some types of cancer known to be linked to inherited genes:

Acquired Cancer-Causing Mutations 

Acquired cancer-causing mutations, also known as somatic changes, are at the root of most cancers. Sometimes, these mutations happen as a result of exposure to carcinogens. However, they can occur any time a cell divides. 

Carcinogens can cause cancer by causing direct damage to DNA in cells or speeding up cell division, which increases the risk of mutations. 

Factors that Cause Genetic Mutations 

Many environmental and lifestyle factors can contribute to the development of cancer.

These include: 

Genetic Testing for Cancer 

If you’re concerned about your cancer risk due to your family history, a healthcare provider can help you determine whether genetic testing for cancer is right for you. Depending on your individual situation, the results of your genetic testing may empower you to take steps to reduce your risk or to schedule cancer screenings for earlier detection and treatment. 

That said, genetic testing is not always helpful and can’t predict the future—which means your test results could also lead to stress and anxiety or even a misunderstanding of the results. According to the American Cancer Society (ACS), it’s best to talk to a trained genetic counselor rather than diving in on your own with an at-home genetic test.

Know your rights regarding genetic predisposition

Several laws help protect you against genetic discrimination in regard to access to health insurance and employment. However, these do not protect you if your employer has fewer than 15 employees or for other forms of insurance such as life, disability, or long-term care insurance.

Testing for Inherited Genes 

With a referral from your healthcare provider, you can meet with a specialist for genetic counseling. If you determine you want to have genetic testing done, you can send off a blood or saliva sample to a lab. There, it can be examined for changes in your DNA that could indicate genetic mutations for different types of cancer. 

Your genetic counselor can help you review your results to learn more about your hereditary cancer risk and next steps to consider to lower your cancer risk. 

Testing for Mutations to Cancer 

If you’ve recently been diagnosed with cancer, your healthcare providers may also recommend a different form of genetic testing known as genomic testing which examines the genetic makeup of cancer cells specifically.

These tests can come with many benefits. They may help better determine your prognosis, risk of cancer recurrence, and which treatments will (or won’t) work most effectively for your cancer type.

A Word From Verywell 

While cancer is genetic, the impact of your genes, lifestyle, and environment on your potential cancer risk can be complex and confusing. If someone close to you has recently been diagnosed with cancer or you’re concerned about your family history, ask your healthcare provider about genetic counseling.

With their help, you can empower yourself and gain some peace of mind with tools like genetic testing, lifestyle changes, and regular screenings.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Genetics and Cancer: Family Cancer Syndromes. American Cancer Society. August 2020.

  2. National Cancer Institute. Genetic testing for inherited cancer susceptibility syndromes. March 2019.

  3. American Cancer Society. Genetics and cancer: Should I get genetic testing for cancer risk? May 2016.

  4. MedlinePlus. What is genetic discrimination? September 2020.

  5. American Cancer Society. Genes and cancer: How genes can help in the diagnosis and treatment of cancer. June 2014.

By Lauren Krouse
Lauren Krouse is a journalist especially interested in covering women’s health, mental health, and social determinants of health. Her work appears in Women's Health, Prevention, and Self, among other publications.