One in vivo study showed that granulocyte macrophage colony-stimulating factor (GM-CSF) from Kras-mutant cells promotes the recruitment of myeloid-derived suppressor cells (MDSCs), which inhibit the antitumor activity of CD8 + cytotoxic T cells in a mouse model of pancreatic cancer with Kras and Trp53 mutations12. This evidence concerns the gene CSF2 and pancreatic neoplasm.