CELF2 and non-small cell lung carcinoma: A mechanistic investigation revealed circLIFR suppresses NSCLC progression by regulating CELF2 (CUGBP Elav-Like family Member 2) and inactivating PTEN (Phosphatase and Tensin homolog)/AKT (serine/threonine-protein kinase) signaling pathways by sponging miR-429.