POU2F3 and small cell lung carcinoma: Given the differences in survival based on NOTCH1 expression using NMF-defined subsets, we next sought to validate our results using previously defined subsets: Rudin et al. (28) (ASCL1, NEUROD1, POU2F3, YAP1) and Gay et al. (16) (SCLC-A, SCLC-N, SCLC-I, SCLC-P).