CLDN4 and posterior cortical atrophy: Specific inhibitors of dominant negative Ras and downstream effectors of mitogen-activated protein/Erk and phosphatidylinositol 3’-kinase inhibit Ras signaling, thereby decreasing claudin-4 expression and in GC, which further increases PI3K and Akt phosphorylation, thus promoting tumor cell proliferation, migration, invasion, and tumorigenesis, a mechanism that may be similar in PCa (38, 39, 75).