DDR1 and neoplasm: Previous studies indicated that DDR1 could promote tumor progression by inducing cell adhesion and differentiation, which might be due to: (i) coexpressing with adhesion molecules [22]; (ii) promoting epithelial-mesenchymal transition (EMT) [21, 23]; (iii) participating in functional interaction of Notch1 and NF-κB pathway [24, 25].