DDR2 and neoplasm: DDR1, a collagen receptor, is the tyrosine kinase receptors subfamily widely expressed on the surface of tumor cells.[9] DDR1 overexpression promotes the tumor‐collagen interactions in ECM, leading to fibroblasts activation and increased collagen production.[10] Phosphorylation of DDR1 and DDR2 on linear collagen fibers has been reported to associated with matrix‐mediated drug resistance (MMDR) in melanoma.[11] DDR1 has become a new target for tumor therapy as its role in regulating MMDR.