Myeloid-derived suppressor cells (MDSCs), which play an important role in tumor and inflammatory diseases, are divided into two subsets CD11b+Ly6ChiLy6G− monocytic MDSC (Mo-MDSC) and CD11b+Ly6Clow/negLy6G+ polymorphonuclear MDSC (PMN-MDSC) with different immunosuppressive function. The gene discussed is ITGAM; the disease is neoplasm.