In tumor bearing-mice, MDSCs were characterized by co-expression of CD11b and Gr-1, which were further divided into two subtypes: CD11b+Ly6G+Ly-6Chigh monocytic MDSCs (M-MDSCs) and CD11b+Ly-6G+Ly-6Clow polymorphonuclear MDSCs (PMN-MDSCs), which were usually present in bone marrow, peripheral blood, spleen, liver, lung or various organs (14). Here, ITGAM is linked to neoplasm.