PAICS and neoplasm: We selected the top 10 key proteins, namely, Eprs, Gart, Umps, Paics, Atp5o, Hadha, Dld, Mrpl4, Rpl8 and Mrpl13, in the upregulated KEGG pathways of B16-F10 tumour-bearing PMN-MDSCs as targets to screen the natural inhibitors of PMN-MDSCs from the traditional Chinese Medicine library (20000 compounds).