POU5F1 and cancer: Western blot assay showed that silence of PCAT3 or PCAT9 decreased the protein levels of OCT4, SOX2, NANOG and VEGF in LNCaP and 22Rv1 cells, suggesting that PCAT3 and PCAT9 may modulate the properties of angiogenesis and cancer stem cells in PCa (Figure 3C and 3D).