Skin cancer is one of the most common cancers in the world. In fact, one in every three cancers diagnosed is skin cancer, with nearly 2 million cases world-wide. Risk factors involved in developing skin cancer can vary greatly depending on family history and where you live, but genetic makeup may play a larger role in our risk of developing skin cancer than was originally thought.
If you’ve got fair skin, live in Australia and have a history of sunburns throughout your life, odds are pretty high that you’ll develop skin cancer in the future. But did you know that if you’re a man, you’re almost 20% more likely to be diagnosed with skin cancer than a woman? In fact, men are more likely to develop skin cancer on their head, neck and trunk while women are more likely to develop skin cancer on their legs. At first thought, one could assume that this variation in cancer location may be due to habit, but studies have shown that on average, men are born with more moles on their head, neck and trunk and women are born with more moles on their legs. This begs the question of whether or not our risk of skin cancer is genetically predisposed.
It’s proven that the more moles an individual has, the more likely they are to develop skin cancer later in life. Of course, those living in sunny climates may develop more moles over time, but how do our genes determine how many moles we have and where they’re located? Recent discoveries have shown that in women, 70% of the moles found on their legs could be explained by genetics, meaning that women are genetically predisposed to skin cancer on their legs. The genes involved in the number of moles present in women are also linked to genes that appear to promote melanoma development, explaining why most women are diagnosed with skin cancer from moles on the legs versus the neck or trunk, where men are more likely to develop skin cancer.
Another study conducted at the University of Queensland has attempted to uncover the underlying genes behind specific types of moles that can lead to skin cancer. According to Associate Professor Rick Sturm, there are three classes of mole that are involved in skin cancer. The idea behind this work is to understand the risk of each class and be able to determine an individuals likelihood of developing cancer-based on the number of moles they have in each class versus just the total number of moles they have.
The study involved nearly 1200 individuals. The moles on each individual were looked at under a microscope and compared to their DNA. Through the study, it was found that certain gene types directly influence the number of certain mole types. The IRF4 gene, for example, was found to strongly influence the number of globular mole types found on the body. These mole types vary in their risk factor, but the idea of the study is to better understand the risk factor of an individual based directly on their genes, mole types and mole patterns.
The link between genes and skin cancer are still in their infancy, but it’s clear that genes play a massive role in our risk factor. Soon genetic testing will be a critical tool for clinicians in diagnosing, treating, and most importantly preventing skin cancer.