We examined the cell frequency of immunosuppressive MDSCs identified within the CD11b+Gr-1+ population and found a striking RNase1-mediated decrease in granulocytic MDSCs, which represent more than 80% of all MDSCs in most types of cancer and primarily cause antigen-specific T cell suppression, but we found no change in monocytic MDSCs, which suppress T cell responses in both antigen-specific and antigen-nonspecific manners not requiring cellular contact 51, 52 (Figure 3F, Ly-6G+Ly-6C- vs. Ly-6G-Ly-6C+). This evidence concerns the gene RNASE1 and cancer.