Rubin et al. conducted a genetic study using RNA expression in SCLC cell lines derived from mice, dividing SCLC into four biological subtypes, SCLC‐A, SCLC‐N, SCLC‐P, and SCLC‐Y, based on different transcriptional regulatory factors, ASCL1, NEUROD1, POU2F3, and YAP1, respectively. The gene discussed is POU2F3; the disease is small cell lung carcinoma.