PAI‐1 is reported to be involved in various cancer cell properties such as migration, invasion and proliferation.8, 27, 28, 29 Several studies showed PAI‐1 was involved in these processes through association with apoptosis,18 PI3k/Akt, MAPK17, 30 and TGF‐β signalling including EMT.10, 24 In this study, when CAFs were treated with a PAI‐1 inhibitor, the greater number of proteins related to apoptosis were up‐regulated as compared to that of MAPK or TGF‐β signalling proteins as observed by quantitative proteomic analysis. This evidence concerns the gene SERPINE1 and cancer.