Retinoic acid (RA) is described as an inhibitor of prostate cancer cell growth. me utilized reverse transcription-polymerase chain reaction (RT-PCR) to analyze expression of different isoforms of fibroblast growth factor 8 (FCfF8) in response to RA. Results in the prostate cancer cell line LNCaP show that whereas overall expression levels of FGF8 appear to remain constant, RA addition induces an inversion of the ratio between FGF8a and -b mRNAs. Along with this observed " isoform switch," unexpected expression of retinoic acid receptor alpha was detected. Although preliminary, these data allow one to hypothesize on the existence of a possible link between the morphogenic hormone RA and the regulation of the potent mitogen FGF8.