DDR2 (discoidin domain receptor tyrosine kinase 2) is a cell surface receptor tyrosine kinase that binds fibrillar collagen and regulates tissue remodeling processes 1. The protein functions as a collagen-activated receptor that promotes extracellular matrix remodeling through upregulation of matrix metalloproteinases and facilitates cell migration and proliferation 2. In skeletal development, DDR2+ stem cells contribute to calvarial mineralization through a distinct form of endochondral ossification, with DDR2+ cell expansion occurring as a maladaptive response to other stem cell depletion in craniosynostosis 1. DDR2 serves as a biomarker for cardiac fibroblasts and plays roles in cardiac tissue remodeling 3. In pathological contexts, DDR2 promotes cancer progression through multiple mechanisms: in ovarian cancer, stromal DDR2 enhances metastasis by regulating glycolytic metabolism and extracellular matrix protein secretion, particularly LOXL2 4, while DDR2-regulated arginase activity in cancer-associated fibroblasts promotes collagen production and tumor invasion 2. In hepatocellular carcinoma, DDR2 activation through β-catenin signaling contributes to epithelial-mesenchymal transition and metastasis 5. DDR2 is also being investigated as a potential therapeutic target in lung cancer treatment 6.