ARG1 and neoplasm: We previously reported that MDSCs isolated from the tumor or inflamed prostates have high expression levels of Arg1 and Nos2 mRNA but that neither CD11b+Gr-1+ MDSCs isolated from the periphery of tumor-bearing mice nor MDSC subtypes (M-MDSc, PMN-MDSCs) isolated from the periphery of mice with inflamed prostates express these genes (12).