When a DNA Repair Gene Turns Against the Cell: Scientists…

When a DNA Repair Gene Turns Against the Cell: Scientists Uncover a New Cancer Vulnerability DNA repair systems are among the body's most important defenses against cancer. They constantly monitor genetic material, fixing damage before harmful mutations can accumulate. But what happens when one of these protective mechanisms becomes too active? Researchers at Penn State College of Medicine have discovered that a DNA repair gene called EXO1 may become harmful when produced in excessive amounts. Instead of protecting the genome, the overactive gene appears to create DNA damage that can contribute to cancer development. The findings also reveal a potential opportunity: tumors with high levels of EXO1 may respond especially well to certain targeted cancer therapies. Under normal conditions, EXO1 plays an important role in maintaining genomic stability. The gene produces a protein that acts like molecular scissors, trimming damaged sections of DNA during the repair process. This helps cells maintain healthy genetic information as they grow and divide. However, researchers found that when cells produce too much EXO1, those molecular scissors become overly aggressive. Instead of repairing damaged DNA, excessive EXO1 begins cutting DNA structures that should remain intact, creating new genetic damage rather than preventing it. The research team analyzed cancer databases and discovered that elevated EXO1 levels occur in a significant proportion of tumors. Increased EXO1 activity was observed in several cancer types, including: *