(54) investigated CLDN7 in various renal tumors and found striking differences: CLDN7 was completely absent (0% positive) in clear cell RCC (ccRCC), the most common and aggressive subtype, whereas it was expressed in 67% of chromophobe RCC, 28% of papillary RCC, and 26% of oncocytomas. Here, CLDN7 is linked to nonpapillary renal cell carcinoma.