Cda and Dctd were not differentially expressed in fibroblasts and tumour cells at the mRNA level in vitro (see online supplementary figure S4), however, immunohistochemistry clearly demonstrated that Cda and Dctd were expressed at very low levels in stromal cells and robustly expressed in neoplastic cells in human and murine PDAC (figure 5E and online supplementary figure S6A, B). Here, CDA is linked to neoplasm.