STAT3 and lung cancer: The STAT3 inhibitors combined with rapidly accelerated fibrosarcoma (RAF) inhibitor or ALK inhibitor effectively suppress the survival of Kras-mutated or ALK-rearranged lung cancer cells by abrogating the activation of mitogen-activated extracellular signal-regulated kinase (MEK)/extracellular regulated protein kinases (ERK) signaling pathway [55,56].