Olivia Munn diagnosed with breast cancer despite a clear mammogram and testing negative for genes that increase risk

• Olivia Munn said she was diagnosed with breast cancer and underwent a double mastectomy in 2023.
• Munn said she had a normal mammogram and tested negative for known genes linked to cancer risk.

Olivia Munn, the actor who starred in "X-Men: Apocalypse," said she was diagnosed with breast cancer and underwent a double mastectomy after routine testing failed to flag "an aggressive, fasting moving" type of cancer.

Munn, 43, posted on Instagram Wednesday, telling followers that an extra precaution from her doctor may have saved her life.

Munn said she had undergone preventive testing in February 2023, which found she was negative for 90 different genes linked to cancer, including BRCA, the most well-known gene linked to breast cancer. She had also recently had a normal mammogram.

But Munn's doctor, whom she referred to as her "guardian angel," opted to take the additional step of calculating her Breast Cancer Risk Assessment Score, taking into account factors such as age and family history, according to Munn.

The test revealed Munn had a 37% lifetime risk, prompting her doctor to call for an MRI, followed by an ultrasound and biopsy.

Munn was then diagnosed with Luminal B cancer in both breasts in April 2023, two months after she thought she was in the clear based on the initial tests. This type of breast cancer tends to progress faster and have a worse prognosis than other subtypes, the Susan G. Komen Breast Cancer Foundation says on its website.

Munn said she has since undergone four surgeries, including a double mastectomy, and wanted to share her experience in the hope of helping others at risk.

"I'm lucky. We caught it with enough time that I had options," she wrote. "I want the same for any woman who might have to face this one day."