Immunohistochemical staining of renal carcinoma and nontumorous renal tissue sections when bound with ZT-2 peptide-fluorescein isothiocyanate. To investigate if the free ZT-2 peptide maintained its binding affinity to renal carcinoma cells, we made a synthetic peptide ZT-2 (QQPPMHLMSYAG) labeled with fluorescein isothiocyanate. (A) Immunohistochemical staining of renal carcinoma tissues when bound with phage ZT-2-FITC. The specific binding sites on tumor cells fluoresced green (B) Immunohistochemical staining of nontumorous renal tissues when bound with phage ZT-2 (C) a negative control section stained with random peptide-fluorescein isothiocyanate in renal carcinoma tissues. Magnification × 200.