STAT3 and lung cancer: An increasing number of ceRNAs has been reported to be involved in the cellular signaling pathways of lung cancer, such as in β-catenin signaling, the PI3K/AKT signaling pathway, the PTEN pathway, the IGF-2 signaling pathway, Wnt signaling, the STAT3/p-STAT3 pathway, and transforming growth factor-β (TGF-β) signaling (Tables 1–3).