L1CAM and neoplasm: CAFs in tumour tissues are thought to be a pool of heterogeneous cells that play tumour-promoting and tumour-suppressive roles.1, 2, 3, 5 Although the net function of CAFs is thought to be tumour promoting in many types of cancer, CAF depletion rather worsens the prognosis in mouse models of pancreatic cancer.6, 7 In this study, Mint3/L1CAM depletion in CAFs decreased tumour growth of co-injected MDA-MB-231 and A431 cells.