KRAS and lung adenocarcinoma: In advanced lung adenocarcinoma cases, KRAS G12D-triggered pancreatic ductal adenocarcinoma (PDAC) has been repeatedly demonstrated to secrete a large amount of granulocyte monocyte colony-stimulating factor (GM-CSF), suppressing immune function partially by improving the number of tumor-associated Gr-1+ CD11b+ myeloid cells.