Finally, we identified 26 different papers describing 28 case-control studies (11 case-control studies for prostate cancer, 14 for bladder cancer, and three for renal cell carcinoma, Table 1, Fig. 1) [9–34] to evaluate the association of MTHFR rs1801131 A/C. The gene discussed is MTHFR; the disease is renal cell carcinoma.