In this study, using the transwell in-vitro co-culture system to mimic the breast cancer stromal microenvironment, we show that the presence of mature human adipocytes can enhance the proliferation, migration and invasion capabilities (Fig. 2a–i) in two breast cancer cell lines (MDA-MB-468 and MCF-7) and induce an EMT-phenotype, characterised by decrease expression of E-cadherin and increased expression of vimentin and ZEB1 (Fig. 3b,c). This evidence concerns the gene ZEB1 and breast cancer.