PDX1 and pancreatic ductal adenocarcinoma: To elucidate the role of SMAD4 in antitumor immunity, we used CRISPR/Cas9 technology to knockout Dpc4 gene encoding SMAD4 in PDAC, a murine pancreatic ductal adenocarcinoma cell line derived from pancreatic tumor tissue of an LSL‐KrasG12D/+, LSL‐Trp53R172H/+, Pdx‐1‐Cre (KPC) mouse (Figure1A), and two individual clones were used for this study.