To identify Ras effector pathways that regulate YAP levels in PC tumors expressing oncogenic K-RasG12D, HPAF/CD18 cells were exposed to inhibitors of the MAPK pathway (U0126), PI3K pathway (LY294002) [65,83], and Rac1 GTPase (EHT-1864) [68,69]. The gene discussed is RAC1; the disease is pachyonychia congenita.