Gray hair might represent the marks left by our bodies in the battle against cancer, according to a new study.

The recently released Natural Cell Biology explores how the cells that provide pigment in our hair and skin “self-destruct” upon damage, as part of the body’s protective measures against cancer.

Researchers have found that when these pigment-producing cells experience certain types of damage, they cease to function on their own instead of continuing to divide.

This selection process helps to prevent the spread of faulty cells that can cause harmful mutations, but it ultimately leads to a decline in pigment-producing cells over time, resulting in gray hair.

While scientists have been examining methods to prevent the self-destruction of pigment cells to combat gray hair, recent findings indicate that gray hair may indicate a significant anti-cancer defensive mechanism.

“[This study] indicates that gray hair and melanoma are not unrelated occurrences but are framed as varied outcomes of stem cell stress responses,” stated Professor Emi Nishimura of the University of Tokyo, who spearheaded the research.

The Tokyo team made this revelation while examining mouse melanocyte stem cells, which are responsible for producing hair pigment. They found that these melanocyte cells only sacrificed themselves when their DNA faced a “double-strand break,” or a precise cut on both sides of the DNA helix.

However, when the cells encountered different stressors, like ultraviolet light or carcinogens, they did not undergo self-destruction. Instead, they survived and continued to divide, allowing mutations to accumulate and potentially paving the way for cancer.

These two distinct responses—cells opting for self-sacrifice in some situations but persisting in others—may help clarify why gray hair and skin cancer become increasingly prevalent as we age.

Researchers suggest that gaining a deeper understanding and ultimately controlling this response could lead to innovative methods for eliminating high-risk cells before they turn cancerous.

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