GSTP1 and renal cell carcinoma: No publication biases for the relationship between the GSTM1-null genotype or GSTT1-null genotype and RCC risk was determined in the overall population (GSTM1: Begg P = 0.692, Egger P = 0.400; GSTT1: Begg P = 0.166, Egger P = 0.095; GSTM1-null/GSTT1-null genotype: Begg P = 0.917, Egger P = 0.628; GSTP1 A/G gene polymorphism: Begg P = 0.902, Egger P = 0.290; Fig. 5).