Expression of FGF receptors 1 through 4 (FGF-R1-4) in myeloma and stromal cells.

(A) FGF-R1-4 expression in 2 myeloma cell lines (U-266, OPM-2) using RT-PCR. Note the FGF-R3 overexpression in OPM-2 cells. (B) Flow cytometric detection of FGF-R1-4 in U-266 myeloma cells stained by sandwich labeling using polyclonal rabbit antihuman antibodies directed against FGF-R1-4 and a goat antirabbit FITC-labeled secondary antibody. UC indicates unstained control; IC, isotype control. (C) FGF-R1-4 transcripts in purified marrow myeloma cells of representative patients. Note the FGF-R3 overexpression in the t(4;14)-positive MM patient (UPN no. 47). (D) Amplified FGF-R1-4 transcripts in marrow stromal cells from a representative myeloma patient (MM-BMSCs) and a control subject (control-BMSCs). The product size for each receptor isotype is indicated on the left. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as a control for RNA integrity. + indicates transcript detectable by RT-PCR; −, no transcript detectable by RT-PCR.