Four studies were mainly retained, namely the articles from Bui et al., Zhang et al. (mentioned above), Patard et al. [25] and Chamie et al. [26] High CAIX expression seemed to be associated with lower tumor stage (pT1T2 vs. pT3T4), lower tumor grade (G1G2 vs. G3G4), absence of nodal involvement (N0 vs. N+) and favorable ECOG score (0 vs. ≥1). The gene discussed is CA9; the disease is neoplasm.