GREM1 and colorectal cancer: This is consistent with previous reports in which Grem1 was found to be highly expressed in CAFs in the microenvironment of basal cell carcinoma (and other tumors) compared to normal tissue counterparts [23] and a study of colorectal cancer, in which Grem1 was found to be expressed at the invasion fronts in CAFs and to mediate the loss of cancer cell differentiation [3].