As far as TFE3-rearranged renal cell carcinomas were concerned, despite the cutoff taken into account, a negative expression of CA9 (p = 0.0001) and CD13 (p = 0.0003 with a 5% cutoff and p = 0.0001 with both a 10% and a 20% cutoff) statistically correlated with the diagnosis of such tumor subtype, as well as cathepsin K (p = 0.0001), AMACR (p = 0.0001), and parvalbumin (p = 0.0021) positivity. Here, CA9 is linked to hereditary clear cell renal cell carcinoma.