EPHA1 and medulloblastoma: Because medulloblastoma subgroups differ in development and microenvironmental wiring, the Eph/ephrin system there argues strongly for subgroup-stratified target selection and for prioritizing receptor-ligand pairs with validated functional impact (Sikkema et al., 2012; McKinney et al., 2015; Morrison et al., 2013; Bhatia et al., 2015; Gokhale et al., 2010; Kool et al., 2008).