CTLA4 and nonpapillary renal cell carcinoma: After controlling for the univariately significant parameters age, gender, tumor grade, tumor stage, and ECOG performance status, CTLA-4 expression in TIMC remains independently prognostic for OS (HR = 2.8, p = 0.013) and CSS (HR = 3.7, p = 0.048) in the whole cohort (Table 6), as well as in the ccRCC-only subgroup analysis (HR = 4.1, OS p = 0.006; CSS HR = 8.2, p = 0.003) (Table 7) and in the primary non-metastatic subgroup analysis (OS HR = 3.4, p = 0.028; CSS HR = 7.4, p = 0.022) (Table 8).