PTEN and cancer: CSCs in different cancers are commonly deregulated in critical developmental and signaling pathways including Wnt, Notch, Janus kinase/signal transducers and activators of transcription (JAK/STAT), Hedgehog, phosphatidylinositol-3-kinase (PI3K)/phosphatase and tensin homolog (PTEN), and nuclear factor kappa B (NF-κB) (Matsui, 2016; Figure 3B).