Previously, we observed a direct correlation between CD98hc expression in clear cell renal cell cancer (ccRCC) and grade of differentiation [6]: We now analyzed CD98hc expression in paraffin-embedded tumor tissue sections derived from 51 ccRCC patients: The aggressive and less differentiated G3 and G4 ccRCC tumors were characterized by high CD98hc (G3: 87.0%; G4: 100.0%) expression, while the more differentiated G1 ccRCC revealed no CD98hc expression (G1: 0.0%). This evidence concerns the gene SLC3A2 and nonpapillary renal cell carcinoma.