Clock disruption speeds breast cancer in models ^{CEFR B1}

Circadian rhythms are the body’s natural 24-hour clock and they regulate sleep, hormones, tissue repair and immune surveillance. New work from a team at Texas A&M University shows that repeated disruption of this clock changes healthy breast tissue and weakens immune defenses, which together speed breast cancer in experimental models.

The researchers, led by Tapasree Roy Sarkar, used genetically engineered models that develop aggressive breast cancer. One group lived on a normal light–dark cycle and another on a disrupted cycle that disturbed internal clocks. Compared with the normal group, the disrupted animals developed signs of cancer earlier and their tumors were more aggressive and more likely to spread to the lungs.

At the molecular level the team identified LILRB4, a receptor that normally limits inflammation. In the tumors it acted like an immune checkpoint and helped suppress immune attack. When researchers targeted LILRB4, the tumor environment became less immunosuppressive and showed reduced metastasis and tumor growth, even with circadian disruption. The team plans further work on reversing these effects in people who work irregular hours.