GSTM1 and renal cell carcinoma: However, further meta-analysis to detect the risk of the GSTM1-null/GSTT1-null genotype for RCC susceptibility showed no association between the GSTM1-null/GSTT1-null genotype and RCC susceptibility in the overall population of Caucasians, compared to hospital-based controls, when only high-quality studies were recruited in the meta-analysis.