NEUROD1 and small cell lung carcinoma: Clinical therapeutic research in SCLC has entered the fast track in recent years, underpinning this progress has been the proposal of a new model of SCLC subtypes defined by relative expressions of ASCL1, NEUROD1 with a high NE program, and POU2F3, YAP1 with a non‐NE program, named as SCLC‐A, SCLC‐N, SCLC‐P, and SCLC‐Y, respectively.9