Researchers from the University of Tokyo, led by Professor Emi Nishimura, have demonstrated that graying hair is not only a sign of aging, but also a protective response of the body to DNA damage.
The study published in Nature Cell Biology shows that melanocyte stem cells, responsible for the production of melanin, can follow two paths: either they age and lose the ability to produce pigment, generating white hair, or, under special conditions, they become cancer cells, informs Noi.md with reference to .
Experiments on mice have shown that exposure to X-rays induces DNA damage in stem cells, causing them to differentiate and stop proliferating, which causes graying. This process is regulated by the tumor suppressor genes p53 and p21, which protect the body against the uncontrolled development of tumors.
The research also explains why moles don’t always turn into melanoma: the affected cells age and stop proliferating, thus preventing the development of cancer. However, if cellular stress comes from carcinogens, such as UVB rays or chemicals, stem cells can bypass protective mechanisms and become cancerous by activating the Kit molecular signal.
Professor Nishimura concludes that the loss of hair pigment and the development of melanoma are not independent events, but divergent manifestations of the stem cells’ response to stress. Graying, rather than preventing cancer, reflects a natural safety mechanism, eliminating potentially dangerous cells before they become malignant.
This discovery opens new perspectives in understanding the link between aging, DNA protection and cancer prevention, providing important clues for future therapies against melanoma and skin and hair degenerative processes.
