Figure 5.

Immunostaining of normal kidney and renal cell tumors for CA IX/CA XII expression. The normal kidney is negative for CA IX (A) whereas CA XII is expressed in the distal convoluted tubules (arrow) and intercalated cells of the collecting ducts (arrowhead) (B). Co-expression of CA IX and CA XII is seen in renal cell carcinomas of the clear cell type (CA IX = C; CA XII = D). However, chromophobe cell carcinomas (E) and oncocytomas (G) do not express CA IX whereas they exhibit diffuse expression of CA XII (F and H, respectively). Original magnifications, ×200 (A and B) and ×400 (C–H).