It's been well documented that people with red hair also have a higher risk for developing certain types of skin cancer, but new research published on Thursday may shed light as to why.
It turns out that the same genetic mutation that gives people red hair also triggers a cancer-causing pathway when they are exposed to ultraviolet radiation, according to a team of researchers at the Beth Israel Deaconess Medical Center and Boston University School of Medicine.
A person's skin pigment, which can give a person red hair or fair skin, is influenced by the melanocortin-1 (MC1R) gene receptor. The MC1R mutation that underlies a person's red hair and the cancer-causing pathway (P13K/Akt) may help explain why red-headed individuals have a higher risk of developing melanoma, the most deadly type of skin cancer, accounting for 75 percent of all skin-cancer deaths.
"Our findings provide a possible molecular mechanism as to why red-haired individuals harboring MC1R mutations are much more susceptible to UV-induced skin damage than individuals with darker skin, resulting in a 10-to-100-fold higher frequency of melanoma," said co-author Wenyi Wei, in a statement.
The National Cancer Institute estimates that there will be nearly 77,000 new cases of melanoma in the United States in 2013, and close to 9,500 deaths.
Melanoma is the least common type of skin cancer, and is rare because it is believed to be a multi-step process of genetic mutations that eventually increase a person's susceptibility to ultraviolet radiation, the report says. Both UVA and UVB rays can mutate the DNA in a person's skin cells and lead to melanoma.
In normal cases, the MC1R gene receptor is protected from cancer by binding with the tumor-suppressing gene known as PTEN. But in red-headed individuals, PTEN was absent and there was increased activity in the cancer-causing pathway that boosted cell growth and synchronized with another gene mutation associated with melanoma.
Wei said these findings could serve as a starting point for other studies, and that it remains unclear why only MC1R mutations associated with red hair, and not other variants, are unable to bind with PTEN.