IDO1 and nonpapillary renal cell carcinoma: In a 76-year-old female patient diagnosed with Grade 2 ccRCC, there was a ~2.45-fold increase in the expression of IDO in the tumorous section compared to the adjacent healthy sample; and another ~4.65-fold IDO overexpression was also detected in a 65-year-old patient with a Grade 3 ccRCC tumor (Table 2).