KRT7 and neoplasm: For a negative subset of CCRCCs and ROs, very focal (<10%) and mild-to-moderate staining for CK7 (Figures 5(a) and 5(c)) or Claudin-7 (Figures 5(b) and 5(d)) was also appreciated in some tumor cells that are usually located on the wall of cystic structures or within sclerotic/edematous stroma.