Going grey is often seen as a normal part of getting older, but new research suggests greying hair could actually be the body’s way of protecting itself from melanoma, a serious type of skin cancer.
The study, from The Institute of Medical Science at The University of Tokyo, found that greying hair may happen when the body tries to stop damaged cells from turning cancerous.
Researchers explained that when DNA in the body becomes damaged – which can happen from things like sunlight, pollution and even certain foods – special cells that give colour to hair and skin may change. These cells are called melanocyte stem cells.
Normally, these cells help keep hair coloured, but the study found that when these cells are damaged, the body can trigger a process called “seno-differentiation”. This process shuts down the pigment cells to stop them from becoming harmful, causing hair to turn grey.
Without seno-differentiation, the damaged cells could continue growing and may become cancerous.
The research was published in the journal Nature Cell Biology and shows that the same cell activity that causes hair to turn grey is also linked to the way melanoma forms.
Researchers tested this by studying mice and looking at how the pigment-producing cells reacted to DNA damage. They found that the cells often lost colour quickly, turning grey, to protect the body.
However, the study also found that this protective process does not always work. In some cases, cancer-causing agents, such as ultraviolet (UV) rays from the sun, can stop the greying process. When this happens, damaged cells can keep growing, raising the risk of melanoma.
Lead author Professor Emi Nishimura said, “These findings reveal that the same stem cell population can follow antagonistic fates – exhaustion or expansion – depending on the type of stress and microenvironmental signals. It reframes hair greying and melanoma not as unrelated events, but as divergent outcomes of stem cell stress responses.”
While this discovery is important, experts say it does not mean that people who go grey are protected from cancer. Instead, the study shows that greying is the body’s natural defence system trying to get rid of damaged cells.
More research is needed to learn how this process works in humans and whether it could help in future cancer treatments.
For now, experts continue to remind Australians to protect their skin by wearing sunscreen, avoiding too much sun exposure and having regular skin checks.
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