The inclusion of subtype-specific markers (ASCL1, NEUROD1, POU2F3, and maybe YAP1) for immunohistochemistry staining besides neuroendocrine markers, such as SYP and NCAM1, will benefit the physicians in diagnosing patients with specific SCLC subtypes and predicting the potential treatment response. The gene discussed is NEUROD1; the disease is small cell lung carcinoma.