IL4 and neoplasm: In an earlier study, it was found that Salmonella-mediated tumor regression induced the phenotypic and functional activation of intratumoral myeloid cells, but not that of splenic CD11b+ cells, making them significantly less immunosuppressive in the TME; this observation was attributed to the significant reduction of IL-4-IL-13/ARG1 axis, a prototypical marker for immunosuppressive tumor-associated macrophages [34].