Millions of People May Carry Hidden Genetic Cancer Risks, Study Finds

FRIDAY, Oct. 31, 2025 — Millions of Americans could unknowingly carry genetic mutations that significantly increase their risk for cancer, even if they have no family history of the disease, a new study suggests.

Widespread Hidden Mutations

As many as 5% of Americans—roughly 17 million people—carry genetic variants linked to cancer, according to findings published this week in the Journal of the American Medical Association (JAMA).

The study’s results indicate that these cancer-associated genetic mutations may be far more common in the general population than previously thought.

“Genetic testing has traditionally been reserved for individuals with strong family histories or other high-risk indicators,” said senior researcher Dr. Joshua Arbesman, a dermatologist at the Cleveland Clinic.

“Our findings show that many people with pathogenic variants fall outside those criteria, suggesting we may be missing opportunities for early detection and prevention.”

Beyond Family History

The researchers emphasized that cancer-linked gene mutations can be present in people regardless of family history or lifestyle factors such as smoking, alcohol use, diet, or exercise.

For the study, the team analyzed more than 70 common cancer-related genes, identifying over 3,400 unique mutations that raise the risk of developing cancer.

“Our findings show how widespread cancer risk variants are,” Arbesman added. “This research highlights the importance of regular cancer screenings for all Americans — not just those with a family history or other risk factors.”

Previous Research and Implications

The study builds on earlier work by the same research team, which found that genetic predisposition to melanoma was 7.5 times higher than national guidelines had estimated.

“Knowing the prevalence of gene variants in the general population gives us a clearer picture without any pre-assumptions based on lifestyle or family history,” said Ying Ni, an assistant professor of translational genomics at the Cleveland Clinic.

Encouraging Broader Screening

Researchers hope their findings will support broader access to genetic testing and routine cancer screenings, such as mammograms and colonoscopies, even for those considered low-risk.

“Early detection remains the best defense against cancer,” Arbesman said. “Long term, we hope to build a truly comprehensive list of genes that guide cancer screening and prevention, so we can identify people who would benefit from proactive care.”

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