DDR1 and breast cancer: In order to determine whether DDR1 may functionally interact with the IGF-IR, we first evaluated by immunoblot DDR1 and IGF-IR expression in a panel of IGF-I-responsive human breast cancer cell lines (MCF-7, T47D, ZR-75, MDA-MB-157, MDA-MB-231, BT-474), and in human HepG2 hepatoblastoma cells.