CHGB and neuroendocrine carcinoma: Cluster #1 highly expressed some classical neuroendocrine marker genes (such as chromogranin B gene CHGB and secretogranin-3 gene SCG3), and the sampling regions of cluster #1 (PT5, LN1-1, LN1-2, LN1-3 and LN1-4) were classified as as NEC according to the histopathological features.