POU2F3 and small cell lung carcinoma: Of interest, none of the markers previously identified as specific to pure histology LCNEC [8] or SCLC [29] (ASCL1, DLL3, NOTCHs, NEUROD1, POU2F3, YAP1) has been identified as differentially expressed in any CoLCNEC cluster while the direct comparison with other lung cancer molecular profiles highlighted a strong similarity to carcinoids described by Alcala et al. [23] and Laddah et al. [24] suggesting a strong neuroendocrine lineage of this cluster.