IMMUNOHISTOCHEMICAL LOCALIZATION OF CYTOKERATIN-17 IN TRANSITIONAL-CELL CARCINOMAS OF THE HUMAN URINARY-TRACT

The expression of cytokeratin (CK) 17 was studied in 28 primary transi tional cell carcinomas (TCCs) of the human urinary tract using CK 17-s pecific monoclonal antibody E3. While CK 17 was not detectable at all or only present in some areas of basal cells in normal - appearing uro thelium, a certain subpopulation of cells of all G1 and G1/G2 TCCs exa mined (9 cases) stained positive for CK 17. These latter cells were ei ther restricted to the basal compartment or located also in suprabasal layers exhibiting a decreasing intensity of immunoreactivity. CK 17 w as seen in practically all cells in G2 and G2/G3 tumors (7 cases). In contrast, G3 TCCs and anaplastic carcinomas showed a highly variable C K 17 staining pattern ranging from completely negative to completely p ositive with several intermediate phenotypes. Our results indicate tha t CK 17 could be a useful marker for the progression of urinary tumors .