It was characterized by low gene expression of ASCL1 and DLL3 and overexpression of INSM1, with variable expression of POU2F3, NOTCH1, and YAP1. The fourth cluster was composed of EPNEC cases, except for one case of P-LCNEC, and was characterized mainly by MYCL1 and YAP1 overexpression and low expression of all other genes. Here, POU2F3 is linked to large cell neuroendocrine carcinoma.