CXCL5 and pancreatic ductal adenocarcinoma: For example, in human pancreatic ductal adenocarcinoma (PDAC), infiltrating fibroblasts generate a dense stromal infiltrate (34), and genetic approaches to eliminate Col1 from myofibroblasts in PDAC mouse models accelerate tumor progression owing to the emergence of a CXCL5-expressing tumor cell population that suppresses antitumor immunity by recruiting myeloid cell–derived suppressor cells (24).