BRUSSELS — A new study suggests that gray hair could be more than just a sign of aging — it might also reflect the body’s built-in defense mechanism against cancer.
Researchers from the University of Tokyo discovered that when hair follicle stem cells experience severe DNA damage, they initiate a self-elimination process to prevent the development of melanoma, a type of skin cancer.
The study, published in Nature Cell Biology, explains that white or gray hair results when pigment-producing melanocyte stem cells destroy themselves instead of replicating damaged DNA. This prevents potentially cancer-causing mutations from spreading.
According to lead researchers Emi Nishimura and Yasuaki Mohri, the process is triggered by key molecular signals that command the damaged cells to self-destruct. Under certain stressors—such as exposure to ultraviolet B (UVB) radiation or chemical carcinogens—these same stem cells might instead continue dividing, which could lead to uncontrolled growth.
While experts emphasize that gray or white hair does not directly protect against cancer, the research offers fresh insight into how the body maintains balance between cell death and cell renewal.
“These findings reveal that the same population of stem cells can follow opposing fates — exhaustion or expansion — depending on the type of stress and microenvironmental signals,” said Nishimura. “This redefines hair graying and melanoma not as unrelated events but as divergent outcomes of stem cell responses to stress.”
The study provides a new perspective on aging hair as a visible marker of the body’s cellular defense mechanisms, deepening our understanding of stem cell biology and cancer prevention. (Anadolu)
