Olivia Munn Reveals Her Mother Was Also Diagnosed with Breast Cancer, Underscoring the Importance of Genetic Risk Awareness
Actress and activist Olivia Munn has spoken candidly about her own battle with breast cancer since being diagnosed in 2024. Now, she’s revealing that her mother, Kim Munn, has also faced the disease — a discovery made after taking the same risk assessment test Olivia credits with saving her life.
In an Instagram post shared on July 9, Munn, 45, wrote:
“You may know that when I talk about my own battle with cancer I bring up the Lifetime Risk Assessment test that saved my life. I never would’ve predicted it would save my mom’s life as well.”
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Munn was diagnosed with Luminal B breast cancer in both breasts — a particularly aggressive subtype. In response, she underwent a double mastectomy. To further reduce her risk of recurrence, she also had a hysterectomy and a bilateral salpingo-oophorectomy, procedures that remove the uterus, ovaries, and fallopian tubes.
Her mother’s recent diagnosis brings renewed attention to the role of family history and inherited genetic mutations in breast cancer risk. Experts say this underscores the importance of early screening and genetic testing, especially for those with a known family history or BRCA gene mutations.
“[Genetic] tests look at the genes you were born with; therefore, one test will be truly lifelong,” said Dr. Louise Morrell, a medical oncologist and chief medical executive at the Lynn Cancer Institute, part of Baptist Health South Florida.
Healthline spoke with Dr. Morrell to better understand how genetic factors influence breast and other cancers — and why awareness and testing can be critical, even lifesaving. Around 5–10% of breast cancer cases are linked to inherited genetic mutations, making family history a key factor in proactive healthcare decisions.
This interview has been edited and condensed for clarity.
How Family History Influences Cancer Risk
Family history plays a significant role in cancer risk, largely due to inherited genetic mutations. According to Dr. Louise Morrell, some of the most powerful cancer-related genes — like BRCA1 and BRCA2 — dramatically increase the risk for breast and ovarian cancers. However, these mutations are relatively rare, occurring in about 3 to 4 out of every 1,000 people, and account for only approximately 5% of all breast cancer cases.
“There are also less potent cancer genes that contribute to breast cancer at a much lower rate,” Dr. Morrell explains. “These are found in about 10% of the breast cancer population.”
The presence of other cancers in the family — such as pancreatic or prostate cancer — may also point to a hereditary cancer syndrome. These syndromes are linked to high-risk mutations that can increase the likelihood of developing multiple cancer types.
“Generally, the highly potent cancer genes such as BRCA are ‘cancer syndrome’ genes,” says Dr. Morrell. “A family history involving multiple types of cancer can be a clue that a shared genetic mutation is driving risk.”
Understanding these genetic connections allows for targeted screening, early intervention, and informed decision-making — not only for the individual but potentially for their relatives as well.
The Most Common Genetic Mutations Linked to Hereditary Cancer
According to Dr. Louise Morrell, the most commonly identified genetic mutations associated with hereditary cancers include BRCA1, BRCA2, and PALB2, which are primarily linked to breast and ovarian cancers. Additionally, mutations in the so-called Lynch syndrome genes — such as MLH1, MSH2, MSH6, and PMS2 — are associated with increased risks of colon and uterine cancers.
“The good news,” Dr. Morrell noted, “is that one comprehensive gene panel test can now screen for all of these cancer-related mutations at once.”
This expanded access to broad-spectrum genetic testing enables earlier risk assessment and more personalized approaches to prevention, screening, and treatment.
The Importance of Cancer Screening and Personalized Risk Assessments
While family history is a well-known indicator of cancer risk, most cancers actually occur in individuals without a strong family history, explains Dr. Louise Morrell. That’s why personalized risk assessments — which take into account genetics, lifestyle, and other factors — are critical for identifying those who may benefit from earlier or more intensive screening.
“Most cancers remain unexplained by family history,” Dr. Morrell notes. “But other factors can help identify individuals who will benefit from screening tests. More importantly, a negative test for a well-known gene does not rule out the contribution of familial factors.”
She also addressed a common misconception: that testing positive for a BRCA mutation automatically leads to a recommendation for preventative mastectomy.
“The most common misconception is the belief that we will advise removal of the breasts for the BRCA gene,” she says. “While some individuals choose this option, most do not. Instead, we often recommend enhanced screening, such as breast MRI, which can significantly improve early detection.”
This balanced, personalized approach to cancer prevention helps patients make informed decisions based on their unique risk profiles — not just genetic test results alone.
Frequently Asked Questions
How much does family history affect my cancer risk?
Family history can be an important indicator of cancer risk, particularly when associated with high-risk genetic mutations like BRCA1, BRCA2, or Lynch syndrome genes. However, most cancers actually occur in individuals without a known family history, which is why risk assessment tools consider multiple factors beyond genetics.
What are the most common genetic mutations linked to hereditary cancer?
The BRCA1, BRCA2, and PALB2 genes are strongly linked to breast and ovarian cancers. Lynch syndrome–related genes, including MLH1, MSH2, MSH6, and PMS2, are associated with colon and uterine cancers. These mutations may also increase the risk for other cancers like prostate or pancreatic cancer.
How common are BRCA gene mutations?
BRCA mutations are found in about 3 to 4 out of every 1,000 people. While they significantly increase cancer risk, they account for only about 5% of all breast cancer cases.
What if I test negative for BRCA or other well-known genes—am I in the clear?
Not necessarily. A negative result for known mutations doesn’t eliminate your cancer risk. Other genetic, environmental, and lifestyle factors may still contribute. Also, there may be undiscovered or less potent genetic mutations at play.
Will I be advised to have a preventive mastectomy if I test positive for BRCA?
This is a common misconception. While some individuals choose preventive surgery, most do not. Many are advised instead to undergo enhanced screening, such as annual MRIs, which can aid in early detection and treatment.
What is a risk assessment test and why is it important?
A risk assessment test evaluates your personal and family health history to estimate your likelihood of developing cancer. When combined with genetic testing, it helps identify people who may benefit from earlier or more frequent screening — even if they don’t have a strong family history.
Conclusion
Olivia Munn’s story — and now her mother’s — underscores the life-saving potential of genetic testing, risk assessment, and early detection. While powerful genetic mutations like BRCA and Lynch syndrome genes are well-known, most cancers arise without a clear family history, making personalized screening strategies more important than ever.
As Dr. Louise Morrell emphasizes, understanding your genetic makeup is only part of the equation. A comprehensive approach that includes personal and family history, lifestyle factors, and access to preventive care can empower individuals to make informed decisions about their health.