STAT3 and neoplasm: Binding of the ligand, IL-6, to the α-subunit of its receptor (IL-6R) results in the formation of a heterodimeric complex (IL-6R/gp130) which activates Janus kinase (JAK) and various downstream effectors such as signal transducer and activator of transcription 3 (STAT3), SHP-2/Ras, mitogen-activated protein kinase (MAPK), and phosphatidylinositol-triphosphate kinase PI3K/Akt, critical for cell proliferation, apoptosis evasion and survival, drug resistance, and inactivation of tumor suppressors [252–258].