Tejal Somvanshi
Actress Olivia Munn announced Wednesday that her mother, Kim Munn, has been diagnosed with Stage 1 HER2 breast cancer, the same disease that Munn herself battled beginning in 2023. The 45-year-old actress shared the news in an emotional Instagram post, highlighting how the same risk assessment test that detected her own cancer also saved her mother’s life.
“My mother was diagnosed with breast cancer,” Munn wrote. “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.”
After Munn’s own diagnosis in 2023, she urged both her mother and sister to take the Breast Cancer Lifetime Risk Assessment test. Despite having a clear mammogram during her yearly screening, Kim Munn scored 26.2% on the Tyrer-Cuzick Risk Assessment test, well above the 20% threshold that doctors consider high risk for developing breast cancer.
The high score prompted Munn to insist her mother get an MRI, which led to the discovery of Stage 1 HER2 breast cancer. HER2-positive breast cancer is known to be fast-growing and invasive, with cancer cells having too many copies of the HER2 gene that promotes rapid cell growth.
“Going through cancer is really hard,” Munn shared. “But there’s something about watching a loved one go through it that is even more heartbreaking.”
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Kim Munn has since completed 12 rounds of chemotherapy and will continue receiving monthly Herceptin transfusions until this fall. Herceptin is a targeted therapy that specifically blocks the HER2 protein’s growth signals. She also underwent a double mastectomy, similar to the procedure Munn had following her own diagnosis.
The post included several touching moments from Kim’s treatment journey, including a video of her ringing the bell after completing chemotherapy, surrounded by hospital staff with supportive signs. Another video shows her cooking fried green tomatoes just days after surgery, demonstrating her resilience.
“I want to say how proud I am of my mom,” Munn wrote. “She’s handled all of this with bravery and humor while still driving us crazy. Just days after her double mastectomy, she tried to do laundry and make dinner – she’s insane.”
Munn’s husband, comedian John Mulaney, has been by both women’s sides throughout their treatments. Photos show him supporting Kim during her hospital visits and chemotherapy sessions.
Munn herself was diagnosed with aggressive Luminal B breast cancer in April 2023 after the same risk assessment prompted further testing despite negative mammograms and genetic testing. She underwent a double mastectomy in May 2023, just one month after her diagnosis, and has had multiple surgeries since.
Both cases highlight the limitations of standard mammograms, especially for women with dense breast tissue, where tumors can be harder to detect. The Tyrer-Cuzick model considers numerous factors beyond standard screenings, including age, ethnicity, reproductive history, family cancer history, prior breast biopsies, and breast density.
Munn is encouraging all women to take the free online risk assessment. “Anything above 20% is considered high risk for breast cancer and you should insist that your doctor order a breast MRI,” she wrote, adding that her mother wanted to share her story in hopes of saving others’ lives.
The actress has become a vocal advocate for proactive health measures since her diagnosis, emphasizing the importance of self-advocacy in healthcare decisions and comprehensive screening beyond traditional mammograms.
