YAP1 and meningioma: Using the RCAS/tv-a system (RCAS = Replication-Competent Avian sarcoma-leukosis virus long terminal repeat with a Splice acceptor, tv-a = tumor virus receptor A), which helps facilitate a somatic gene transfer in transgenic mice, researchers have demonstrated that the exogenous expression of constitutively active YAP1 is sufficient to induce NF2 mutant-like meningiomas in mice (34).