This is one of these things that is really “lovely” to read as a freckled, blue-eyed redhead with a birthmarked, blue-eyed redheaded sister.
Sweden’s Lund University has concluded a study that indicates that melanoma occurs with greater frequency in subjects with red hair – specifically, redheads with freckles. I guess that might be one reason that they say redheads are going to be extinct within the next century, right there with our general rarity:
just 4 percent of the world’s population carries the red-hair gene. The gene is recessive and therefore diluted when carriers produce children with people who have the dominant brown-hair gene.
The Swedish study isolates the gene that carries traits associated with redheadedness – hair color, obviously, but also eye color, freckles, low tanning ability, tendency toward birthmarks – and concludes that the relationship between malignant melanoma and this gene is pretty dang significant. Additionally, there is a strong tie between melanoma and the number of birthmarks a person has.
I found a 2004 article by Hans Rorsman, a (redheaded, for what it’s worth) scientist at Lund University, about the ginger gene. It’s pretty hard to plow through – guess I should have taken that semester elective in high school microbiology instead of jazz band – but I’m kind of piecing together some of it to make sense. I guess there’s something called 5-S-cysteinyldopa that is a “biochemical marker” of melanoma:
At our clinical department a melanoma patient with red hair exhibited rapidly progressing disease. We obtained excised metastatic tissue for analysis which proved that extracts of the metastasis contained a catecholic compound seemingly identical with the unknown compound we had previously observed. With the information available from Naples on cysteinyldopa as a precursor of phaeomelanin we concentrated our analytical work on 5-S-cysteinyldopa. All examinations performed on our catecholic compound extracted from the melanoma-produced evidence for the presence of 5-S-cysteinyldopa in the tissue.
Experimentation on (actual) guinea pigs, whose pigmentation chemistry presumably mirrors that in humans, found that the level of 5-S-cysteinyldopa was ten times higher in red guinea pigs than in black ones.
Even Wikipedia has something to say on the subject, complete with helpful links for us laymen:
Melanin in the skin aids UV tolerance through suntanning, but fair-skinned persons lack the levels of melanin needed to prevent UV-induced DNA-damage. Studies have shown that red hair alleles in MC1R effect increased freckles and decreased tanning ability. It has been found that Europeans who are heterozygous for red hair exhibit increased sensitivity to UV radiation.
Red hair and its relationship to UV sensitivity are of interest to many melanoma researchers. Sunshine can both be good and bad for a person’s health and the different alleles on MC1R represent these adaptations. It also has been shown that individuals with pale skin are highly susceptible to a variety of skin cancers such as melanoma, basal cell carcinoma, and squamous cell carcinoma. Due to this sensitivity many people have advised redheads to wear sunscreen.
The American Academy of Dermatology asserts that melanoma is more common, not only in redheads, but in those with blue or green eyes. For those keeping track, the majority of redheads have either blue or green eyes. (A fair number have brown; I’m being highly unscientific here, but I imagine some have gray and hazel as well. Those featured in Stephanie Meyer’s upcoming YA vampire novel, Auburn Star, are known to have red eyes.)
I found an interesting Letter to the Editor from Jan. 1989 in the Western Journal of Medicine. In it, Dr. Dennis Clayson disputes a July 1988 article that misleadingly suggested that redheads were at lower risk for melanoma. He points out that the original author’s assertion doesn’t take into account the statistical scarcity of red hair:
In a study of the projected images of hair color, a survey of the population of seven American cities including Denver and Salt Lake City showed that 57.2% had brown hair, 25.7% were blonde, 11. 1 % had black hair, and only 6.0% were redheaded.2 As can be seen in Table 1, the authors’ data actually show that redheads are more than twice as likely to have a malignant melanoma as would be expected if hair color were not a factor.
The original article’s author, Dr. William Robinson, responded in agreement:
Regardless, we agree that persons with red hair are at higher risk for the development of malignant melanoma than those with other hair colors.
I was brought up to wear sunscreen and stay out of the sun, and have of late taken to using a face moisturizer and powder that include SPF sun protection even when I don’t plan to be outdoors much. I know that there has been buzz lately about the inefficacy or potential harm of sunscreen use, but what are you going to do? It’s all about the hats, long sleeves when you can, seeking out shade, and keeping an eye on any change in your skin texture.