show Abstracthide AbstractWe defined pan-cancer binary classes based on distinct expression of YAP (and its paralog TAZ/ WWTR1) and YAP-responsive adhesion regulators. Combining informatics with in vivo and in vitro gain- and loss-of-function studies across multiple murine and human tumor types, we showed that opposite pro- or anti-cancer YAP activity functionally defines binary YAPon or YAPoff cancer classes that express or silence YAP, respectively. Essentially all leukemia and lymphoma fall into the YAPoff class, as do multiple neural and neuroendocrine YAPoff solid cancers. YAPoff solid cancers are frequently RB1-/-, such as retinoblastoma, small cell lung cancer and neuroendocrine prostate cancer. YAP-silencing was intrinsic to the cell-of-origin, or acquired with lineage-switching and drug-resistance. The binary cancer groups exhibit distinct YAP-dependent adhesive behavior, and pharmaceutical vulnerabilities, underscoring clinical relevance. Mechanistically, whereas YAP induces cell cycle genes in YAPon cancers, extensive RNAseq data showed that forced YAP expression in YAPoff cancers instead activated adhesion genes that are normally co-silenced with YAP. YAP regulates both of these anti-cancer adhesive or pro-cancer cell cycle programs through the TEAD DNA binding family (TEAD1-4). YAP/TEAD targets AP1-bound enhancers in YAPon cancers, but Chipseq studies revealed that in YAPoff cancers, YAP/TEAD instead targeted elements co-bound with neural and neuroendocrine lineage-defining basic helix-loop-helix (bHLH) and Homeobox transcription factors (e.g. NEUROD, ASCL1, NKX2, OTX2). A CRISPR screen revealed that, among the adhesion regulators, ITGAV/ITGB5 pair are required for YAP induced cytostasis in YAPoff cancers. YAP is thus pivotal across all cancer, but in opposite pro- or anti-cancer ways, which define contrasting genetic and drug sensitivities. Overall design: TEAD4 ChIP-Seq in 2 retinoblastoma cell lines and 2 small cell lung cancer (SCLC) cell lines expressing an Empty vector (control sample) or YAP (Y79 - wild type; other lines overactive 5SA mutant) in duplicate.