Skin cancer and obesity share genetic link

Behind the Headlines

Monday March 4 2013

Variations in the FTO gene may make people prone to overeating

"A gene previously shown to be linked to obesity may also increase the risk of a deadly form of skin cancer," BBC News reports. The news comes from a study investigating the genetic factors associated with malignant melanoma, the most serious form of skin cancer.

The study looked at single-nucleotide polymorphisms (SNPs), which are variations in a single nucleotide, or 'letter', of DNA. Some SNPs can have a significant effect on human health and development.

The researchers discovered that several SNPs found in a region of the FTO gene are associated with an increased risk of melanoma. Previous research found that certain variations in the FTO gene may be linked to obesity and body mass index (BMI), as mice with these variations had a tendency to overeat. However, the SNPs identified in this study were in a different region of the FTO gene and are not associated with BMI.

This interesting research suggests that the FTO gene is associated with more than just BMI. However, we can't tell if the variations actually do contribute towards melanoma, or how.

Whatever your genetics, the most important and well-established risk factor for melanoma (and other types of skin cancer) remains overexposure to sunlight and artificial sources of UV light, such as sunbeds and sun lamps. Read more about reducing your melanoma risk.

 

Where did the story come from?

The study was carried out by a team of international researchers as part of the Melanoma Genetics Consortium, and was funded by a number of sources including the European Commission, Cancer Research UK, the Leeds Cancer Research UK Centre and the US National Institutes of Health.

It was published in the peer-reviewed journal Nature Genetics.

The BBC and the Daily Mail both covered the research accurately.

 

What kind of research was this?

This was a case-control study where the researchers analysed the genomes of people who developed melanoma (the cases) and the genomes of people without melanoma (the controls).

The aim of the research was to determine whether changes in one base of DNA called single-nucleotide polymorphisms (SNPs) were present more frequently in people with melanoma.

This type of study highlights the association between melanoma and certain SNPs and other variants of DNA, but it cannot prove that these variations cause an increased risk of developing melanoma.

 

What did the research involve?

The researchers analysed SNPs from people of European origin in 1,353 people with melanoma and 3,566 people without melanoma. They hoped to identify SNPs that were associated with melanoma.

The researchers then looked to see if the SNPs they identified as being associated with melanoma were also associated with melanoma in another group of cases and controls (the replication group). They replicated their findings in 12,314 people with melanoma and 55,667 people without melanoma from Europe, Australia and the US who had European ancestry.

As the SNP the researchers identified was located in a region of the FTO gene that was found to be associated with obesity, the researchers then looked to see if the association still existed after adjusting for BMI. This was so they could rule out the possibility that obesity contributes towards the development of melanoma, and not other FTO gene variants.

 

What were the basic results?

The researchers initially identified three SNPs in the FTO gene that were significantly associated with melanoma.

One SNP (rs16953002) was associated with 32% increased odds of melanoma (odds ratio (OR) 1.32, 95% confidence interval (CI) 1.17 to 1.50)

This SNP was also associated with melanoma in the replication group of 12,314 people with melanoma and 55,667 people without melanoma (OR 1.14, 95% CI 1.09 to 1.19).

SNPs in a different part of the FTO gene have been associated with obesity. However, the researchers found no significant association between rs16953002 and BMI in the people involved in this study, and the association between rs16953002 and melanoma existed even after BMI was adjusted for.  

 

How did the researchers interpret the results?

The researchers conclude that they have identified a new region of the genome that is associated with an increased risk of melanoma.

This new region was in the gene FTO. Although variations in this gene have already been found to be associated with BMI, the variations identified in this study were in a different region of the gene and were not associated with BMI. This suggests that FTO could have a wider function than initially thought.

 

Conclusion

By comparing the genomes of people with melanoma with the genomes of people without melanoma, this study has identified variations in a sequence of DNA that are associated with an increased risk of melanoma.

However, this research does not tell us if the variations in the gene actually contribute towards melanoma. Further research is therefore needed to determine how variations in this gene could play a role in melanoma.

Learning more about the genetics involved in conditions does offer the prospect of discovering new treatments for them, so this is valuable research.

Whatever your genetics, the most important and well-established risk factor for melanoma and other less deadly skin cancers remains exposure to UV light – both natural sunlight and artificial sources of light, such as sunbeds.

Effective ways of lowering your risk of developing melanoma include avoiding exposure to the sun when it is at its hottest (usually between 11am and 3pm), dressing sensibly in the sun, using sunscreen, and never using sunbeds or sunlamps.   

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Analysis by Bazian

Edited by NHS Choices

Links to the headlines

Fat gene 'linked with skin cancer'. BBC News, March 4 2013

Obesity and deadliest form of skin cancer 'have genetic link'. Daily Mail, March 4 2013

Links to the science

IIes MM, Law MH, Stacey SN, et al. A variant in FTO shows association with melanoma risk not due to BMI. Nature Genetics. Published online March 3 2013

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In the UK, 2,000 people a year die from malignant melanoma, and the number is increasing. An expert and members of the public talk about how to stay safe in the sun.

Media last reviewed: 03/05/2016

Next review due: 03/05/2018

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