YAP1 and ovarian carcinoma: Next, we analyzed the phosphorylation and intracellular localization of YAP1. Co-incubation of HEYA8 and OVCAR8 ovarian cancer cells with platelets robustly reduced YAP1S127 and YAP1S397 phosphorylation, whereas total YAP1 levels did not change (Fig. 3a, b).