It will be interesting to examine whether other cancer mutations involving residues predicted to participate in the cis interface of other Eph receptors – such as EphA1 R337Q, EphB1 R327H and I332M, and EphB3 E358K in the first fibronectin type III domain as well as EphA5 G547S, EphA6 T493K and R494M, and EphA7 E482D in the second fibronectin type III domain (http://cancer.sanger.ac.uk/cosmic/) – also have functional consequences on cis associations with ephrins. The gene discussed is EPHB3; the disease is cancer.