EPHA4 and neoplasm: For example, one of the AG receptor members, Plexin D1, has been demonstrated to regulate tumour cell survival through DR function, and its ligand Semaphorin 3E could inhibit its apoptotic pathway to facilitate the proliferation of tumour cells;14 netrin could hamper tumour cell apoptosis by binding to its receptor UNC5;16 and EphA4 mediated apoptosis in the absence of its ligand EphrinB318.