YAP1 and small cell lung carcinoma: Recent molecular studies have established that SCLC lineages fall into a number of distinct subtypes, currently referred to as SCLC-A, SCLC-N, SCLC-Y, and SCLC-P, based on their differences in gene and protein expression of transcriptional molecular neuroendocrine, non-neuroendocrine, or tuft cell-like lineage regulators ASCL1, NEUROD1, INSM1, YAP1, and POU2F3, and of their downstream molecular targets [2].