E2F1 and non-small cell lung carcinoma: Based on the ability of E2F1 to transcriptionally upregulate lncRNA, and E2F1, in turn, is co-regulated by PTTG3P and ILF3, we, therefore, suggest that there is an E2F1-PTTG3P-E2F1 positive feedback loop in NSCLC cells, and MAP2K6 may be one of the important downstream target genes of lncRNA PTTG3P.