Cutaneous malignant melanoma incidences analyzed worldwide by skin type over advancing age of males and females: Evidence estrogen and androgenic hair are risk factors

Abstract

We previously analyzed cutaneous malignant melanoma (CMM) incidences worldwide by sex, age, and Fitzpatrick skin type over time (1955-2007) and found only European-ancestry populations have exponential increasing incidences and about a 2-log increase in the risk between the youngest age groups (0-14 and 15-29 yr). We proposed the increasing incidence over time may be from the spread of Human Papilloma Virus (HPV) found in CMM biopsies, and that the 2-log incidence increase between the youngest age groups might be from developing androgenic hair. The increasing incidence with age may be from white hairs transmitting UV radiation to follicular melanocytes. Here we analyzed CMM incidences over the advancing age of males and females of every skin type (I-VI) worldwide. We found only European-ancestry females have a linear increase in their CMM risk while males of all races have a power function increase in their risk with advancing age. We propose the gradual loss of HPV-infected androgenic follicles with advancing age of only European-ancestry females during and after menopause significantly reduces their CMM risk compared to all males who do not have significant estrogen loss and consequent loss of androgenic hair with advancing age. All other races have females with significantly lower amounts of androgenic body hair so that its loss with advancing age is not significant. These results combined with those in the literature and our previous findings showing CMM has been increasing over time, suggests estrogen synergizes HPV infection of androgenic follicular melanocytes significantly increasing the risk for getting CMM.