To reveal the molecular mechanisms by which ASCs promoted the proliferation of breast cancer cells, we analyzed the secretome in ASCs/MDA-MB-231 direct coculture, including SCF, sCD31, IL-6, monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein-1α (MIP-1α), stromal cell-derived factor-1 (SDF-1), vascular endothelial growth factor A (VEGFA), and tumor necrosis factor α (TNFα). This evidence concerns the gene IL6 and breast cancer.