MDK and neoplasm: ,34,35 We also identified other ligand-receptor interactions that are upregulated in malignant regions, such as the interaction between integrins (e.g., ITGB1, ITGA5, and ITGA3) and various extracellular matrix proteins (e.g., COL4A1, FN1, MDK, and SPP1) (Figure 4D), which may play important roles in angiogenesis to promote tumor progression.36