In contrast to UC tumor specimens, phosphorylation of members of the FGFR family of RTKs was lower in UC cell lines (FGFR1 25%, FGFR2 25%, FGFR3 25%, and FGFR4 0%) which may reflect the presence of stromal cells within the primary tumor samples evaluated. This evidence concerns the gene FGFR4 and neoplasm.