ARG1 and neoplasm: More interestingly, there was a strong correlation between the COX2, PGE2 and ARG1 expression and the accumulation of monocytic (CD14+) or the granulocytic (CD15+) MDSC Lower panels of Figure 3A, 3C and left panels of 3C. These data suggest that aATC induced Th1 cytokines may inhibit the tumor- and MDSC-derived immunosuppressive factors in the tumor microenvironment.