Livers from mice and patients with pancreatic ductal carcinomas bared DTCs that lacked expression of the major histocompatibility complex I (MHC I) and cytokeratin 19 (CK19) tumor antigen, providing evidence for a novel immune escape pathway which involves the evasion of T cell killing upon recognition under endoplasmic reticulum (ER) stress [85]. This evidence concerns the gene KRT19 and pancreatic ductal adenocarcinoma.