POU2F3 and small cell lung carcinoma: First, according to their ASCL1, NEUROD1, POU2F3 and YAP1 mRNA expression patterns – we grouped the cell lines into one of the four respective subgroups: SCLC‐A, SCLC‐N, SCLC‐P and SCLC‐Y (eight, seven, four and seven cell lines, respectively) (Figure 1A, upper panel).