Glutathione S-transferase M1/T1 genotype and melanoma in a Southern Italian population: a case-control study

BACKGROUND: The aim of this study was to assess the frequency of GSTM1 and GSTT1 null genotype in melanoma patients and controls from Sicily and Calabria, two regions of Southern Italy never investigated on this issue before, that present a peculiar gene pool because of their geographical and historical characteristics. METHODS: One hundred and twelve Caucasian melanoma patients and 150 age- and sex-matched healthy controls were examined; their GSTM1/GSTT1 genotype was defined by polymerase chain reaction on a sample of oral mucosa cells obtained by buccal swabs. RESULTS: Odds ratio for melanoma was increased not significantly in case of fair hair/eye color, presence of many naevi or solar lentigines, or history of actinic keratosis, skin cancer or sunburns; frequencies of GSTM1 null, GSTT1 null and all their possible combinations were not significantly different between patients and controls. CONCLUSIONS: Our results, in agreement with worldwide literature, show that melanoma is apparently independent from genetic lack of GSTM1/GSTT1. However, melanoma is notoriously linked to a history of sunburns, and GSTM1/GSTT1 null are a significant risk factor for sunburns. We describe a possible explanation of this apparent contradiction, taking into account the different roles of the multiple components of human skin in photoprotection, and their variable importance in different conditions of exposure to UV radiations. Simultaneous evaluation of a larger number of components of the antioxidant system, to assess their individual contribution to protection against melanoma, is advisable and should be considered in future studies. This could allow to better define risks for each patient and possibly to tailor preventive measures.