Update information. Tumor-associated macrophages (TAMs) are key regulators in tumor progression. Although a role of bone marrow-derived monocytes (Mons) as TAM precursors has been revealed, the dynamic phenotypes of both TAMs and Mons regulated by the tumor microenvironment remain unclear. Here, we constructed an optimized micro-proteomics workflow, which was applicable to the mouse myeloid cells of low cell number. We sorted both TAMs and the corresponding Mons (1×105 per sample) from individual melanoma mouse model in the early stage and the late stage to establish the protein expression profiles by mass spectrum.