From the KEGG pathway enrichment analysis (Fig 5B), we find that the CCEN network is relevant to pathways in cancer, small cell lung cancer, PI3K-Akt signaling pathway, ECM-receptor interaction, focal adhesion and cell cycle, while all these pathways belonging to the later two stages show a stronger correlation than those in the early two stages. Here, AKT1 is linked to small cell lung carcinoma.