To dissect the functional role of ObR in affecting breast cancer phenotype and in sustaining the complex tumor/stroma crosstalk, we stably knocked-down the endogenous expression of ObR in human ER-α positive MCF-7 and in triple-negative MDA-MB-231 breast cancer cells (ObR sh) using lentiviral delivered short hairpin RNA. This evidence concerns the gene ESR1 and breast carcinoma.