When Nobody Wants This star Jackie Tohn learned that her father had been diagnosed with metastatic cancer in January 2025, she had never heard of the BRCA1 gene. His subsequent genetic testing changed that — and changed the course of her own medical care.
Tohn’s father was found to carry a BRCA1 mutation. Because first-degree relatives of a BRCA1-positive patient have a 50% chance of carrying the same variant, Tohn spoke with her doctors and pursued testing herself. In June 2025, she learned she was also BRCA1 positive.
She used that information to make the deeply personal decision to undergo a prophylactic double mastectomy — surgical removal of both breasts to prevent the development of breast cancer. She also plans to undergo an oophorectomy in the future.
What does a BRCA1 mutation mean?
Inherited changes in the BRCA1 gene significantly raise the risk for several cancers. For women, lifetime breast cancer risk is as high as 85%, and ovarian cancer risk ranges from 39% to 58%. Men with a BRCA1 mutation face elevated breast and prostate cancer risk, and both men and women have increased risk for pancreatic cancer and melanoma.
What does this mean for families?
For any patient found to carry a BRCA1 mutation, all first-degree relatives — children, parents, and siblings — have a 50% chance of carrying the same change. Tohn and her father’s story shows why genetic testing matters both for patients with an active cancer diagnosis and for those without one.
Do you have a personal or family history of cancer? Talk to your healthcare provider about whether genetic testing is right for you.