To complement the siRNA screening of factors in the CPSF, CstF, CFIm, and CFIIm complexes, we examined three publicly available gene expression datasets wherein primary prostate cancer and metastatic CRPC tissues were analyzed.30–32 CPSF1, and to a lesser extent CPSF4, displayed consistent upregulation in CRPC tumors relative to primary tumors (Figure 2A). This evidence concerns the gene CPSF4 and prostate cancer.