AXL and mesothelioma: AXL is mainly activated through auto-phosphorylation of its intracellular tyrosine kinase domain, thus inducing PI3K/AKT and Wnt signaling in mesothelioma (17, 18), AKT phosphorylation levels are significantly downregulated after AXL signaling is inhibited in mesothelioma or metastatic breast cancer (17, 19, 20).