G-rich sequence factor 1 (GRSF-1) is a cytoplasmic protein that binds RNAs containing the G-rich element. Several alternatively spliced transcript variants of this gene have been described, but the full-length nature of some of these variants has not been determined. GRSF-1 is up-regulated with prostate cancer progression and down regulated by the differentiating agents phenylacetate and phenylbutyrate. The function of GRSF-1 is uncharacterized, but potential roles include mRNA transport, stabilization, or translation. It might react with G-rich containing mRNA of Bcl2 and Bax indicating a regulation role of GRSF-1 in metastatic prostate cancer.