The Universitat Jaume I discovers one of the genetic causes of the higher risk of men to develop melanoma

A study led by researchers at the Predepartmental Unit of Medicine from the Faculty of Health Sciences in the Universitat Jaume I has discovered one of the genetic causes that explain the higher incidence of melanoma described in men. The results of the study have been published in the journal Biology of Sex Differences.

The research group Genetics of Skin Cancer and Human Pigmentation (Melanogen), coordinated by the lecturer Conrado Martínez-Cadenas, has studied the differences between men and women regarding pigmentation (eye, hair and skin colour), as well as sun response, i. e., the history of sunburn and the existence of irregular spots and freckles caused by sun exposure. This study was conducted with the collaboration of the research group of Dr. Gloria Ribas, from the Incliva Biomedical Research Institute. It involved 1,057 people, 52% of which were melanoma patients from hospitals in Castelló, Valencia, Madrid and Bilbao. “The study included 384 genetic variants and six physical characteristics of individuals. The results show that –having the same genetic variability–, men tend to have lighter skin and a worse response to the effects of ultraviolet rays”, Martínez-Cadenas states.

OESTROGENS ENHANCE SOLAR PROTECTION

Skin cancer is determined both by environmental factors, such as sun exposure, and other genetic factors. In fact, people with light skin or eyes and blond or red hair, have a probability between 20 and 30 times higher of having skin cancer in their life that dark skinned people, who tan easily.

On the other hand, several studies have shown that female hormones promote the production of melanin, the pigment that protects the skin from the sun. In fact, “oestrogens could be the reason why women have a darker skin tone, although the genotype of a man and a woman is the same, so that the risk of skin cancer for women is less. In fact, it is more prevalent in men”, argues Bárbara Hernando, researcher from the Melanogen group at the Universitat Jaume I and coauthor of the work.

This study on melanoma in Spain grew out of a previous research, whose results “showed that men tend to have lighter eyes than women with the same genetic variety”, Martínez-Cadenas adds.

FORENSIC USEFULNESS

The research on the genetics of human pigmentation is important to understand human biology and evolution and the biology of skin cancer. The identification of variants associated with phenotypic characteristics that predispose to skin cancer offers the opportunity to study its association with the risk of skin cancer. In addition, studies carried out by the Melanogen group at the UJI in other fields reveal that the introduction of the 'sex' factor in the prediction model of eye colour, developed for forensic purposes, “improves significantly the success rate in identifying an individual from, for example, a biological sample found at a crime scene”, Martínez-Cadenas explains.

PREVENTION IS BASIC AGAINST MELANOMA

Due to the high number of factors surrounding melanoma, the treatments to combat it have not made much progress in recent years. Therefore, prevention is “the most effective weapon against melanoma: the best way to prevent it is to reduce sun exposure at peak incidence of ultraviolet rays and use sunscreen (at least 30 sun protection factor) and when performing outdoor activities”, Barbara Hernando states. Self-examination and regular visits to the specialist, especially if we detect irregular freckles, or freckles with a non-homogeneous colour or greater than six millimetres in diameter, are essential to prevent this disease”, concludes the researcher.

The Melanogen research group at the Universitat Jaume I, led by Conrado Martínez-Cadenas, develops three main lines of research. The first of these lines is the genetic basis of human susceptibility to melanoma and other skin cancers; the second is focused on the molecular mechanisms and intracellular signalling pathways involved in the genesis and progression of skin cancer, both melanoma and non-melanoma (basal cell and squamous cell carcinomas). And, ultimately, their studies address genetic, hormonal and environmental factors involved in the development of benign pigmented lesions: freckles, nevus, solar lentigo, melasma, etc.

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Hernando, B.; Ibarrola-Villava, M.; Fernández, L. P.; Peña-Chilet, M.; Llorca-Cardeñosa, M.; Oltra, S.; Alonso, S.; Boyano, M. D.; Martínez-Cadenas, C.; Ribas, G. (2016). «Sex-specific genetic effects associated with pigmentation, sensitivity to sunlight, and melanoma in a population of Spanish origin». Biology of Sex Difference 7: 1–9.