What Is Luminal B Breast Cancer? Olivia Munn’s Diagnosis Explained.

Actress Olivia Munn announced on Instagram that she was diagnosed with breast cancer in 2023.

Specifically, Munn was diagnosed with luminal B breast cancer, which is one of the molecular subtypes of breast cancer, according to Dr. Rohit Rao, a breast cancer expert at Mayo Clinic Comprehensive Cancer Center. Luminal B breast cancer accounts for roughly 15% to 20% of all breast cancer diagnoses, Rao noted.

“It tends to be more aggressive and tends to have a higher growth rate,” Rao stated.

Additionally, this type of breast cancer is also more likely to present at a later stage, he said, “So, either with the larger size of the tumor or the cancer already having spread to the lymph nodes.”

Below, Rao explains the signs and who is at risk of this type of breast cancer, as well as what you can do to stay on top of your breast health.

The signs of luminal B breast cancer are the same as other kinds of breast cancer.

“It’s important to highlight that the symptoms are essentially the same as any other kind of breast cancer,” said Rao. “So, it’s not like this is an entirely different kind, which has entirely different symptoms.”

But since it’s a faster-growing breast cancer, it’s important to pay attention to any and all warning signs, he added.

Signs of breast cancer include nipple changes, a new breast mass, bleeding from the nipple and a mass in the armpit, noted Rao.

Breast pain, changes to the size of the breast and dimpling of the breast skin are also red flags, according to the Centers for Disease Control and Prevention.

Who is at risk of luminal B breast cancer?

Luminal B breast cancer is more common in younger patients under 50, according to Rao. (It’s worth noting that Munn was 42 when diagnosed.)

Additionally, people