PDPN and pancreatic neoplasm: When co-cultured with a variety of pancreatic cancer cell lines in Dulbecco’s modified Eagle’s medium (DMEM) / 2% fetal bovine serum (FBS), the populations of PDPN-expressing CAFs increased in a time-dependent manner, especially CAF4 on day 5, compared with CAF monocultures (Figure 6).