MMP1 and cancer: For a more detailed analysis of these genes, we listed these up-/down-regulated ligand-receptor pairs which were most commonly shared across 10 cancer types for the four possible scenarios:i.Expression of both receptor and ligand increased in cancer (Table S1), such as COL11A1-ITGA2, COL7A1-ITGA2, MDK-GPC2 and MMP1-ITGA2.