STAT3 and cancer: Signaling pathways involved in both cancer and stem cells include the Janus kinase (JAK)/signal transducer and activator of transcription-3 (STAT), Hedgehog (Hh), epidermal growth factor (EGF), Notch, mitogen-activated protein kinase (MAP-Kinase)/extracellular signal-regulated kinases (ERK), phosphatidylinositol 3 kinase (PI3K)/acutely transforming retrovirus (AKT), nuclear factor kappa β (NFkβ), Wnt and the transforming growth factor beta (TGF-β) signaling pathways (3,4).