Ye and colleagues conducted IHC staining on adenocarcinoma, squamous cell carcinoma, and various types of pulmonary NENs, including lung typical carcinoid (TC), SCLC, and LCNEC, revealing that the expression of human achaete-scute homolog 1 (hASH1), a regulator of neuroendocrine cells growth, was higher in LCNEC (72.7%) and SCLC (79.2%). This evidence concerns the gene ASCL1 and small cell lung carcinoma.