OXR1 and nonpapillary renal cell carcinoma: Several proteins known to play a role in the progression of ccRCC including dipeptidyl-peptidase 4 lymphocyte cell surface protein CD26 (DPP4) [23], collagen type VI alpha 3 chain (COL63) [24, 25], oxidation resistance 1 (OXR1) [26], superoxide dismutase 2 (SOD2) [27], and collagen triple helix repeat containing 1 (CTHRC1) [28, 29] were expressed at significantly higher levels in 786-O spheroids compared to pVHL spheroids.