For example, the EphB2 receptor has been presented as a putative tumor suppressor gene in PCa [21,28], whereas the EphB4 receptor is known to be both tumor-promoting [22,29] in the presence of its cognate ligand Ephrin B2 (EFNB2) and a tumor suppressor in the absence of EFNB2 [30]. The gene discussed is EFNB2; the disease is posterior cortical atrophy.