Obesity Gene Linked to Skin Cancer

A gene associated with obesity and overeating is also linked to the most fatal skin cancer, malignant melanoma.

Individuals with certain variations in a stretch of DNA within the gene that encodes for the fat mass and obesity-associated protein (FTO), known as intron 8, may have a higher chance of developing melanoma.

Scientists at the University of Leeds (UK) have known that the most critical genetic risk factor for obesity and overeating are variations in a different part of the FTO gene, referred to as intron 1. The multinational team gathered and analyzed data on tumor samples from over 13,000 melanoma patients and nearly 60,000 controls who were people with no melanoma from all over the world.

The consortium focuses on genetic susceptibility to melanoma and has conducted two melanoma genome-wide association studies (GWAS; Phases 1 and 2) using samples from populations of European or Israeli ancestry. Genotypes of the 1,373 cases and 3,571 controls from Phase 1 of the GWAS of melanoma were imputed, giving 2.6 million single nucleotide polymorphisms (SNPs), each tested for association with melanoma risk using geographic region as a covariate.

The authors concluded that for the first time that a variant in FTO has been shown to have a replicable association with a trait without being associated with body mass index (BMI). It is also the first time that any variant in FTO outside intron 1 has been shown to have any association with any trait. Malignant melanoma is the fifth most prevalent cancer among people in the UK. Each year, there are about 12,800 novel cases and approximately 2,200 deaths resulting from the disease.

Mark M. Iles, MD, the lead author of the study, said, "This is the first time to our knowledge that this major obesity gene, already linked to multiple illnesses, has been linked to melanoma. This raises the question whether future research will reveal that the gene has a role in even more diseases?" The study was published on March 3, 2013, in the journal Nature Genetics.

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