Variations in the peroxisome proliferator-activated receptor-γ gene and melanoma risk

There is strong evidence to suggest that the peroxisome proliferator-activated receptor (PPAR)-γ, a member of the nuclear receptor family of transcriptional regulators, mediates tumor suppressive activities in a variety of human cancers. Recently, PPARγ agonists were found to inhibit growth of melanoma cell lines. Here, we tested the possibility that variations in the gene encoding PPARγ (PPARG) influence melanoma risk. Two variations of PPARG (P12A[rs1801282] and C161T [rs3856806]) were investigated in two independent case-control studies with a total of 832 melanoma patients and 790 control individuals. In the first study, homozygous carriers of the rare *T allele of the C161T polymorphism in exon 6 of PPARG were significantly more common among patients with melanoma than among healthy subjects (6.0 vs. 2.0%; P=0.0096) and this association was independent of clinical risk factors such as skin type and nevus count (odds ratio 5.18; 95% confidence interval 1.68-15.96; P=0.0041). This finding, however, could not be replicated in the second case-control study. We therefore conclude that the investigated PPARG polymorphisms are not likely to constitute a significant risk factor for the development of melanoma among German Caucasians.