Accumulating evidence has shown that cancer stroma and bone marrow-derived cells (BMDCs) in the tumor microenvironment (TME) play vital roles in tumor progression. However, the mechanism by which oral cancer stroma recruits any particular subset of BMDCs remains largely unknown. Here we sought to identify the subset of BMDCs that is recruited by cancer stroma. We established a sequential transplantation model in BALB/c nude mice, including (i) bone marrow transplantation of GFP-expressing cells and (ii) co-xenografting of patient-derived stroma (two cases, designated PDS1 and PDS2) with oral cancer cells (HSC-2). As controls, xenografting was performed with HSC-2 alone or in combination with normal human dermal fibroblasts (HDF). PDS1, PDS2, and HDF all promoted BMDCs migration in vitro and recruitment in vivo. Multicolor immunofluorescence revealed that the PDS co-xenografts recruited Arginase-1/CD11b/GR1/GFP quadruple-positive cells, which are myeloid-derived suppressor cells (MDSCs), to the TME, whereas the HDF co-xenograft did not.Screening using microarrays revealed that PDS1 and PDS2 expressed CCL2 mRNA (encoding C-C motif chemokine ligand 2) at higher levels than did HDF. Indeed, PDS xenografts contained significantly higher proportions of CCL2-positive stromal cells and CCR2/Arginase-1/CD11b/GR1 quadruple-positive MDSCs (as receiver cells) than the HDF co-xenograft. Consistently, a CCL2 synthesis inhibitor and a CCR2 antagonist significantly inhibited the PDS-driven migration of BM cells in vitro. Furthermore, intraperitoneal injection of the CCR2 antagonist to the PDS xenograft models significantly reduced the CCR2/Arginase-1/CD11b/GR1 quadruple-positive MDSCs infiltration to the TME. In conclusion, oral cancer stroma-secreted CCL2 is a key signal for recruiting CCR2-positive MDSCs from bone marrow to the TME.