CXCL1 and neoplasm: This may be own to that doxorubicin-induced CXCL1/2 expression in treated tumor cells could attract more CD11b+Gr1+ MDSCs into the tumor microenvironment8 and soluble factors that secreted by treated tumor cells, like TGF-β, can be recognized and trigger miRNAs expression in MDSCs and thus promote proliferation and activation of tumor-expanded MDSCs9, 10, 11.