ARG1 and neoplasm: Administration of miRNA-155-loaded sPEG/GLC (sPEG/GLC/155) nanocomplexes increased miRNA-155 expression in TAMs about 100- to 400-fold, both in vitro and in vivo, and repolarized immunosuppressive TAMs to anti-tumor M1 macrophages through elevating M1 macrophage markers (IL-12, iNOS, and MHC II) and suppressing M2 macrophage markers (Msr2 and Arg1) in TAMs.