DDR2 and cholangiocarcinoma: However, ERBB2, ERBB4, INSRR, PDGFRA, FLT1, FLT4, PTK7, NTRK1, EPHA7, EPHA8, EPHA10, EPHB1, EPHB2, EPHB4, EPHB6, DDR2, ROS1, ROR1, and ROR2 were expressed in significantly lower levels in CCA compared to the normal tissues.