Apart from its clinical value, we proposed the relationship between the so-called “SCLC transformation” in clinical and C-NEC because a subtype classification for SCLC has recently been proposed based on the high levels of key transcriptional regulators, namely ASCL1 (SCLC-A), NEUROD1 (SCLC-N), POU2F3 (SCLC-P), and YAP1 (SCLC-Y) [41]. Here, NEUROD1 is linked to neuroendocrine carcinoma.