DPP4 and breast cancer: Using the iDptYFP mouse, Turley and colleagues showed in two studies that in subcutaneous and orthotopic models of pancreatic cancer LRRC15+ myofibroblasts derive fromDpt+ fibroblasts.4,25 A study by Houthuijzenet al. found that different subsets of cancer associated fibroblasts (CAFs) in breast cancer are derived from CD26+ and CD26- fibroblasts within the mammary gland.26 CD26- fibroblasts gave rise to myofibroblastic CAFs, while CD26+ cells preferentially produced inflammatory CAFs.