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/ Source: TODAY
By Rachel Paula Abrahamson

Hanna Thompson and Metta Siebert refer to themselves as identical, mirror-image twins. They have the same features, but some are opposite. This summer, the twin sisters, 35, learned they had a new concerning mirror feature: tumors in their breasts, one in Thompson's right breast and one in Siebert's left breast.

"I was in shock and disbelief," Thompson said. "I was hoping the twin thing would not continue to this extreme."

Hanna Thompson and Metta Siebert, who consider themselves mirror-image twins, received breast cancer diagnoses just weeks apart.Courtesy of Hanna Thompson

Thompson, a San Francisco-based attorney, made an appointment for a mammogram right after Siebert was diagnosed. She too had felt a lump, but the breastfeeding mom chalked it up to a clogged duct.

“I was sure because of my age I was fine, but I wanted to get it checked out because of Metta,” Thompson said. “As soon as as the doctor walked into the room, I knew it wasn’t good.”

Thompson and Siebert recently learned that they are BRCA2 positive. That means they inherited a gene mutation that can significantly increase their chances of getting breast cancer. They were both diagnosed with stage 2A breast cancer.

Dr. Deborah Axelrod, a surgeon who specializes in breast disease and cancer at NYU Langone Health’s Perlmutter Cancer Center in New York City, said what happened to the twins is not uncommon.

“They share the same genes and chromosomes. They have the same genetic makeup,” Axelrod told TODAY. “It’s likely their mom was a carrier of the mutation.” (Not everyone with the mutation develops breast cancer.)

As for Thompson and Siebert's age, early-onset is usually a signature for hereditary breast cancer, Axelrod said.

Thompson is urging other women to get checked out if they feel anything unusual.

Hanna Thompson and Metta Siebert as babies.Courtesy of Hanna Thompson

“The whole thing is so awful, but Metta saved my ass. I probably would have continued to ignore the lump much longer had it not been for her,” Thompson said. “With cancer, you want to catch it as early as possible.”

Axelrod recommends that women with a family history suggestive of a hereditary syndrome of cancer get genetic testing.

“We have found cancers such as pancreatic, colon, melanoma and uterine to be associated with breast cancer,” she explained.

While Thompson feels “relatively normal,” Siebert, a pediatric nurse practitioner in Kansas City, Missouri, is struggling with nausea, headaches and fatigue. Because they have different hormone receptors, their treatment plans are different.

“The drug I’m taking is a lot less intense than the one Metta is taking,” Thompson told TODAY. “She feels really awful. Going through this at the same time, but being apart is hard."

The twin sisters during happier times.courtesy of Hanna Thompson

Siebert is due to finish her chemotherapy in October, while Thompson should be done in January. They will both undergo bilateral mastectomies.

“Our prognosis is really good,” Thompson said. “But it’s still super scary, so we’re cautiously optimistic.”