Relationship between GSTM1/GSTT1 null genotypes and renal cell carcinoma risk: a meta-analysis

The results from the published studies on the relationship between GSTM1/GSTT1 null genotypes and renal cell carcinoma (RCC) risk are still conflicting. This meta-analysis was performed to evaluate the relationship between GSTM1/GSTT1 null genotypes and RCC susceptibility. Association studies were identified from the databases of PubMed, Embase, Cochrane Library, and CBM-disc (China Biological Medicine Database) on 1 February 2012, and eligible investigations from 1950 to 2012 were synthesized using meta-analysis method. Results were expressed as odds ratios (ORs) for dichotomous data, and 95% confidence intervals (CIs) were also calculated. Six studies were identified for the analysis of association between polymorphic deletion of GSTM1/GSTT1 and RCC risk. There was no association between GSTM1/GSTT1 null genotype and RCC susceptibility (GSTM1: N = 6, p-heterogeneity = 0.07, OR = 1.07, 95% CI: 0.85-1.35, p = 0.57; GSTT1: N = 6, p-heterogeneity < 0.00001, OR = 0.98, 95% CI: 0.58-1.65, p = 0.94). Interestingly, null genotype of GSTT1 was associated with RCC risk in Caucasians and Asians (Caucasians: N = 4, p-heterogeneity = 0.38, OR = 0.76, 95% CI: 0.61-0.95, p = 0.01; Asians: N = 1, OR = 2.39, 95% CI: 1.63-3.51, p < 0.00001). For the GSTM1-GSTT1 interaction analysis, the dual null genotype of GSTM1/GSTT1 was not significantly associated with RCC susceptibility (N = 4, p-heterogeneity = 0.006, OR = 1.17, 95% CI: 0.98-1.39, p = 0.09). However, the dual null genotype of GSTM1-GSTT1 was associated with RCC risk in Asians (N = 1, OR = 2.06, 95% CI: 1.36-3.13, p = 0.007). In conclusion, our study results suggest that GSTT1 null genotype is associated with the RCC susceptibility in Caucasians and Asians, and the dual null genotype of GSTM1-GSTT1 is associated with RCC risk in Asians. However, more genetic epidemiological investigations are required to further explore this relationship.