LDHA expression and LDH activity and MCT1 expression in renal tissue slices. Mean LDHA mRNA expression is higher in ccRCCs than in either normal renal tissues or benign tumors (P = .001 and .016, respectively), and the LDH activity was also correspondingly higher in ccRCC than in either normal renal tissues (P = .020) or benign tumors (P = .030) (A). MCT1 expression is significantly higher in ccRCCs than in both normal renal tissues (P = .006) and benign tumors (P = .002) (B). The sample size of the tissues used for mRNA analyses is as follows: n = 11 for normal renal tissue, n = 3 for benign renal tumors, and n = 7 for ccRCCs. White bars indicate normal renal tissue, gray bars indicate benign renal tumors, and black bars indicate ccRCC, with standard deviation error bars.