Although aberrant activation of YAP1 (Yes1-associated transcriptional regulator) has been reported for several solid cancers, in MCC specifically, an inverse correlation between a neuroendocrine gene signature and the Hippo pathway transcription factor YAP1 was identified at the transcript and protein level in MCC tumor biopsies as well as in established and patient-derived cell lines, distinguishing MCCs based on their intratumoral heterogeneity [117]. The gene discussed is YAP1; the disease is neoplasm.