Based on this background, the present study was designed with two main objectives: first, to assess whether FAP protein expression, as evaluated by immunohistochemistry (IHC), predicts disease recurrence in patients with apparently localized ccRCC who subsequently developed distant metastases; and second, to investigate the association between stromal FAP expression in primary tumors and clinical response to first-line TKI therapy in patients with advanced ccRCC. Here, FAP is linked to nonpapillary renal cell carcinoma.