Type I collagen is a known component of the microenvironment at the host–tumour interface in human colorectal cancer (Brabletz et al, 2004) and is more highly expressed in tumours displaying infiltrative growth compared with those with expansive growth (Oku et al, 2008).Type I collagen also reduces cdx-2 expression in human colorectal cancer cell lines in vitro (Brabletz et al, 2004) and enhances tumourigenicity in human colorectal cancer cells in xenografts (Del-Buono et al, 1991). Here, CDX2 is linked to colorectal cancer.