RNA sequencing of two distinct androgen-dependent models shows PCGEM1 to be considerably expressed, while PRNCR1 showed scant basal expression. PCGEM1 was sharply down-regulated following castration and up-regulated upon AR activation in vivo. A PCGEM1-associated gene expression signature (PES) was significantly repressed in response to androgen ablation therapy and in hormone-refractory versus hormone-nave PCa patients. Furthermore, we found PCGEM1 was uniformly distributed in PCa cell nucleus and cytoplasm which remained unaltered upon AR transcriptional activation. PCGEM1 was up-regulated in primary PCa but not in metastasized PCa.