GM-CSF has been found at significantly high levels in many human PDAC cells and many studies have highlighted that oncogenic KRAS-driven GM-CSF expression in pancreatic intraepithelial neoplasia (PanIN) and invasive pancreatic cancer cells promote an influx of immunosuppressive myeloid cells, which inhibit adaptive immunity [99,100]. This evidence concerns the gene KRAS and pancreatic neoplasm.