Olivia Munn courageously revealed her breast cancer diagnosis in 2023, choosing to keep this significant health milestone private for a full year. This decision highlights the deeply personal and often challenging journey many face when dealing with serious illnesses.

In a heartfelt open letter shared on Instagram in March 2024, the former star of The Newsroom candidly detailed the process of how her luminal B cancer was discovered. She also provided insight into her reasons for keeping this information private until now. Since that time, Olivia has made it her mission to keep her fans updated on her health journey, aiming to raise awareness about luminal B cancer, which is recognized as the most prevalent form of cancer among women in the United States, excluding skin cancers. This type of cancer accounts for about 30% of all new female cancer cases each year, thereby underscoring the importance of early detection and education on the subject.

Stay informed about Olivia’s current health status and delve deeper into her breast cancer diagnosis and treatment journey below.

Understanding Olivia Munn’s Luminal B Cancer Diagnosis

On March 13, 2024, Olivia Munn, known for her role in X-Men: Apocalypse, recounted the moment she learned about her cancer diagnosis in an emotional Instagram post that resonated with many.

“In February of 2023, in an effort to be proactive about my health, I took a genetic test that checks for 90 different cancer genes,” Olivia shared. “Two months later, I received the shocking news that I was diagnosed with breast cancer. Over the past ten months, I have undergone four surgeries and spent countless days in bed. Surprisingly, I’ve only shed tears twice. I’ve chosen to share my experiences with others only when I felt energized, dressed, and capable of leaving the house, especially to take my baby boy to the park. The diagnosis, the worry, the recovery process, and the pain management remained my private battle.”

Olivia explained that her choice to withhold the diagnosis from the public stemmed from her need to “catch my breath and navigate through some of the hardest parts before sharing my journey.”

“Had it not been for my OBGYN, Dr. Thais Aliabadi, calculating my breast cancer risk assessment score, I wouldn’t have discovered my cancer until my next scheduled mammogram in another year,” Olivia continued, emphasizing, “Her decision literally saved my life.”

After evaluating various factors, such as her family’s cancer history and the fact that she had given birth after the age of 30, the doctor concluded that Olivia’s “lifetime risk” of developing breast cancer was 37 percent.

“Due to that score, I was referred for an MRI, which subsequently led to an ultrasound and then a biopsy,” Olivia explained. “The biopsy results confirmed that I had luminal B cancer in both breasts, which is an aggressive and fast-moving type of cancer. Just thirty days after that biopsy, I underwent a double mastectomy. I went from feeling perfectly healthy one day to waking up in a hospital bed after a grueling 10-hour surgery the next.”

Olivia expressed gratitude for her situation, stating that she felt “lucky” because she and her doctor “identified the cancer in time, allowing for various treatment options.” In closing her message, she expressed a desire for all women facing similar challenges to have the same opportunity for early intervention.

Insights into Luminal B Cancer

As stated by City of Hope’s cancercenter.com, luminal B is a type of breast cancer that “expresses estrogen or progesterone (or both) hormone receptors (HR)” and notably “does not express human epidermal growth factor receptor 2 (HER2) proteins.”

Furthermore, the site elaborates that luminal A and luminal B breast cancers differ significantly; luminal B “expresses the HER2 protein, which may accelerate the growth of cancer cells.” Consequently, luminal B breast cancer is generally more aggressive, resulting in a higher grade and poorer prognosis compared to luminal A.

Current Health Status of Olivia Munn

Olivia has bravely undergone several surgeries as part of her treatment, including a double mastectomy and a hysterectomy. Additionally, she has undergone hormone suppression therapy and made the proactive decision to freeze her eggs to preserve her fertility.

Throughout her health journey, Olivia has also embraced motherhood, raising her two children alongside her husband, John Mulaney. The couple welcomed their son, Malcolm Hiệp Mulaney, in November 2021, prior to her breast cancer diagnosis. They later expanded their family with the arrival of their daughter, Méi June Mulaney, in September 2024, who was born via surrogate.

In February 2025, Olivia shared optimistic news about her progress, stating that while she still has “years to go” in her breast cancer treatment, she feels healthy overall. At TIME’s Women of the Year gala, Olivia raised a toast “to good health and to bright days ahead,” sharing a touching anecdote about her daughter Méi, who had been experiencing discomfort and stomach pains. Trusting her “mother’s intuition,” Olivia switched her daughter’s formula, resulting in significant improvement within hours.

“It was one of my proudest moments as a mother,” Olivia reflected. “Seeing her smile and regain her health made me realize that I felt fairly well that day too. I have years of treatment ahead, but on that particular Friday, I felt good, free from the aches and discomfort associated with surgical menopause, and my mental clarity returned, at least for that day. Holding my daughter, I felt immense gratitude for being healthy enough to cherish every moment.”

Despite the ongoing health challenges she faces, Olivia has participated in numerous public events over the past few years. She attended the 2024 Oscars in Los Angeles, just days before publicly announcing her cancer diagnosis, and has graced red carpets with John, including at the SNL 50: The Anniversary Special.