CA9 and neoplasm: Expression prevalence of CAIX increased with histological grade (16% in grade II (p < 0.001) and 30% in grade III (p < 0.001) versus 4% in grade I; Additional file 7: Figure S1C), and tumor size (15% in T2 (p < 0.001) and 30% in T3 (p < 0.001) versus 12% in T1; Additional file 8: Figure S1D).