DDR2 and liposarcoma: Receptor tyrosine kinase (RTK) genes DDR2 (discoidin domain receptor tyrosine kinase 2), ERBB3 (Erb-B2 receptor tyrosine kinase 3), FGFR1 (fibroblast growth factor receptor 1), and ROS1 (ROS Proto-Oncogene 1) are also amplified in dedifferentiated liposarcoma [36].