SERPINE1 and nonpapillary renal cell carcinoma: The purpose of this study was to evaluate the occurrence and expression pattern of PAI-1 in CCRCC by using immunohistochemistry; to assess a possible association between the PAI-1 expression pattern and microvessel density (MVD), the expression of TSP-1, nuclear grade (NG), tumour stage and size; and finally to examine the impact of PAI-1 on tumour progression and cancer-specific survival (CSS) in CCRCC.