SYP and small cell lung carcinoma: SCLC-A and SCLC-N, defined by higher expression of the transcription factors ASCL1 and NEUROD1, respectively, reflect neuroendocrine subgroups through higher expression of neuroendocrine markers (e.g. synaptophysin or CD56), whereas POU2F3-expressing SCLCs (SCLC-P) constitute a variant, non-neuroendocrine phenotype [11].