Gene link to melanoma in younger women

US scientists have found a link between a variant in the gene MDM2, called MDM2 SNP309, and the occurrence of melanoma in younger women. The study, published in the journal Clinical Cancer Research, found that MDM2 SNP309 was significantly more common in women who were diagnosed with melanoma under the age of 50 than in women diagnosed aged 50 or over. Carrying MDM2 SNP309 may thus be an important risk factor for the development of melanoma in younger women.

MDM2 SNP309 is fairly common in the general population and is associated with early onset of several cancers in women, including colorectal cancer, and certain blood and lung cancers. Melanoma, the most deadly form of skin cancer, is more common in women than men under the age of 40, but is equally common in both sexes between 40 and 50 and occurs more frequently in men over 50. This prompted researchers at the New York University School of Medicine and Columbia University, New York, to investigate whether the frequency of MDM2 SNP309 varied among 227 melanoma patients of different sexes and ages.

They found that women with MDM2 SNP309 were, on average, diagnosed with melanoma aged 46, 13 years earlier than women who do not carry MDM2 SNP309, whose average age at diagnosis was 59, although this difference was not statistically significant. They also found that around 40 per cent of women diagnosed with melanoma under the age of 50 were carriers of MDM2 SNP309, compared with only around 16 per cent of women diagnosed with melanoma aged 50 or over. This corresponded to women who carry MDM2 SNP309 having a 3.89 times greater chance of being diagnosed with melanoma under the age of 50 than those without MDM2 SNP309. No differences in the age of melanoma diagnosis were seen in men who carried MDM2 SNP309. The researchers believe the different effects of carrying MDM2 SNP309 between men and women and between women of different ages may result from the affect of the hormone oestrogen on the activity of MDM2.

This is an early study, and further investigations will be required. In particular, the incidence of MDM SNP309 will need to be compared in those who have never had a melanoma. However, if further studies prove the risk associated with MDM2 SNP309, then: 'It is higher than a lot of the other clinical risk factors that we know, such as blistering sunburns, freckling, and family history', said Dr David Polsky, who led the study.

Melanoma is relatively rare, accounting for approximately 10 per cent of all skin cancers, but it also causes the most fatalities. Approximately 1500 people die each year in England and Wales as a result of melanoma. Dr Polsky said: 'Potentially, we have a genetic test that might identify pre-menopausal women who are at higher risk for melanoma...If that's the case, then we might want to have increased surveillance of those patients including more frequent visits to the doctor, more rigorous teaching of skin self-examination, and other preventive steps'.