Gray Hair May Signal Body’s Successful Defense Against Cancer, Research Shows
New research published today indicates that the development of gray hair in mice is linked to the body’s ability to eliminate DNA-damaged cells, potentially preventing the development of skin cancer – a finding that may have implications for understanding cancer development in humans.
Scientists at the University of Tokyo discovered that when stem cells responsible for hair pigment sustain DNA damage, the body initiates a process forcing these cells to mature and exit the hair follicle, resulting in gray hair as a byproduct of this protective mechanism. This “seno-differentiation” process, as researchers termed it, involves a permanent halt to cell division coupled with maturation and clearance. The study, published in Nature Cell Biology, confirmed this in mice, and researchers found elevated levels of a protein called KIT ligand in several human melanoma samples, suggesting a similar process may occur in people.
However, carcinogens like UV radiation and DMBA can override this protective response by increasing production of KIT ligand, essentially signaling damaged cells to survive and multiply, potentially leading to melanoma. Researchers found that mice exposed to these carcinogens did not go gray, and damaged stem cells persisted and spread, forming pigmented spots. This suggests that graying hair could be an indicator that the body is actively working to prevent cancerous growth. Understanding these mechanisms could lead to new strategies for cancer prevention and early detection; currently, melanoma is responsible for the majority of skin cancer deaths. More information about skin cancer can be found at the American Cancer Society.
The research team also observed a puzzling phenomenon in rare cases where patients reported hair regaining color in specific areas, only to later be diagnosed with melanoma in those same spots, suggesting the darkening hair may be a warning sign of cancerous activity. Researchers are now focusing on further investigation into the relationship between aging, hair graying, and cancer risk, and plan to conduct further studies to determine if interventions aimed at preventing gray hair could inadvertently affect melanoma development.
