In order to assess whether CD11b+CD14−MHCII− cells from dogs with cancer could possibly utilize these mechanisms to mediate T cell suppression, we evaluated the expression of ARG1 and iNOS2, as well as the immunosuppressive cytokines TGF-β and IL-10, within this cell population and from PMNs isolated from peripheral blood of healthy dogs. The gene discussed is IL10; the disease is cancer.