Redhead Mice Are at Higher Risk of Melanoma Even without Ultraviolet

The accepted medical advice to people with red hair, fair skin and freckles has not changed. It is vital that you avoid direct sunlight and its harmful ultraviolet rays. To go outside without a big shady hat and high factor sunscreen is to paint a big melanoma shaped target on your back. And now this new evidence gives you more to think about.

Moles into Melanoma

The research began as an investigation into how moles on the skin can transmute into melanoma with exposure to ultraviolet radiation that breaks down our DNA. The study was conducted at the Massachusetts General Hospital in Charlestown and led by Dr. David E. Fisher and published last week in the journal Nature. The experiments were done on mice specially bred to be vulnerable to melanomas. A mouse’s pelt, like human hair has it’s color and texture genetically determined by eumelanin and pheomelanin. The scientists chose black, white and “red-headed” mice so as to simulate a broad range of human coloration.

Redheads…

It became obvious very early on, even before the creatures were dosed with UV under controlled circumstances, that the redheads were particularly prone to melanoma. In fact half of them developed the cancers within the first twelve months and without any UV exposure at all The other two color groups of mice grew cancers only slowly over prolonged time periods, if at all

It was an inescapable conclusion that the pheomelanin pigment in the mice was triggering a harmful chemical reaction within the skin cells. This breaking down of skin cells is called oxidative stress. It takes place when cells manufacture a different form of oxygen molecules as waste.

Healthy cells are untroubled by these waste molecules. However, too much of it will damage the cells and the DNA therein and thus providing the breeding ground for cancer. The findings of this study go a long way toward solving the mystery of dark skin being significantly less likely to suffer melanoma, than light skin, since the is only 2 to four levels greater than that of pale skin. The reddish-yellow pigment that gives rise to tanning resistance is a potential trigger for skin cancer. Dr. Fisher says:

“Even if you’re good about avoiding UV rays — you know, putting on, wearing protective clothes and being careful at the beach — it’s still possible this red pigment is related to carcinogenic activity anyway.”