ARG1 and neoplasm: BMDM or the macrophage cell line Raw264.7 was co-cultured with PY8119 cells to mimic the TNBC microenvironment in vitro, and macrophages were polarized toward pro-tumor M2 phenotype and M2 markers Arg-1, CD206, Fizz-1, Ym1 and IL-10 were upregulated significantly (Fig. 1B and Additional file 1: Fig S1A).