Cheng et al. [50] conducted a meta-analysis that included six investigations for GSTM1, six reports for GSTT1, and four studies for the dual-null genotype for GSTM1 and GSTT1, and reported that no association was found between the GSTM1-null/GSTT1-null genotype and RCC susceptibility. The gene discussed is GSTM1; the disease is renal cell carcinoma.