Figure 5. Schematic summarizing data and working hypotheses.

The following numbers refer to the number in the schematic. 1, Tgfbr2^KO pancreatic epithelial cells secrete abundant CXCL1/CXCL5 due to lack of TGFβ suppression of chemokine expression (6). 2, The CXCL chemokines recruit to the tumor microenvironment myeloid cells (CD11b⁺). 3, In parallel with chemokines carcinoma cells secrete increased level of G-CSF. 4, G-CSF promotes differentiation of myeloid cells to Ly6G⁺ cells, upregulates immunosuppressive genes such as Arg, iNOS, VEGF and upregulate secretion of IL10 making (5) myeloid cells that are immunosuppressive with pro-tumorigenic properties. 6, The net result is enhanced tumor growth and decrease survival.