FIBROBLAST GROWTH-FACTORS AND THEIR SPECIFIC BINDING-SITES IN NORMAL UROTHELIUM AND TRANSITIONAL-CELL CARCINOMA (TCC) OF THE HUMAN BLADDER

In order to further investigate the involvement of FGF1 and FGF2 in th e transitional cell carcinoma of the bladder (TCC), we compared the ex pression of FGF1, FGF2 and their membrane binding sites by biochemical and immunological methods in both human normal urothelium and transit ional cell carcinoma of the bladder. Using a specific enzyme immunoass ay (EIA), we observed that neoplastic tissue exhibited a lower FGF2 co ntent than normal tissue. FGF1 and FGF2 Western-blot analysis revealed in both types of tissues a major FGF1 form with a low molecular weigh t(14 kDa) and a single FGF2 form (21 kDa). Immunohistological studies showed that FGF1 was specifically located in normal of transformed uro thelial cells, while FGF2 was associated with bladder stroma. Binding analysis in tissue membrane preparations revealed a dramatic drop in b oth high and low affinity binding sites for FGF2 in TCC bladder in com parison to normal bladder. FGF2 cross-linking experiments illustrated a qualitative modification of FGF2 binding complexes in tumors. These data suggest that invasive bladder carcinoma is associated with modifi cations of FGF1 and FGF2 tissue levels and alterations in the characte ristics of the FGF2 membrane binding sites