Comparative immunomodulatory properties of mesenchymal stem cells derived from human breast tumor and normal breast adipose tissue. Sineh Sepehr Koushan,Razavi Alireza,Hassan Zuhair Mohammad,Fazel Abdolreza,Abdollahpour-Alitappeh Meghdad,Mossahebi-Mohammadi Majid,Yekaninejad Mir Saeed,Farhadihosseinabadi Behrouz,Hashemi Seyed Mahmoud Cancer immunology, immunotherapy : CII OBJECTIVE:Mesenchymal stem cells (MSCs), one of the most important stromal cells in the tumor microenvironment, play a major role in the immunomodulation and development of tumors. In contrast to immunomodulatory effects of bone marrow-derived MSCs, resident MSCs were not well studied in tumor. The aim of this study was to compare the immunomodulatory properties and protein secretion profiles of MSCs isolated from breast tumor (T-MSC) and normal breast adipose tissue (N-MSC). MATERIALS AND METHODS:T-MSCs and N-MSCs were isolated by the explant culture method and characterized, and their immunomodulatory function was assessed on peripheral blood lymphocytes (PBLs) by evaluating the effects of MSC conditioned media on the proliferation and induction of some cytokines and regulatory T cells (Tregs) by BrdU assay, ELISA, and flow cytometry. In addition, we compared the secretion of indoleamine 2,3-dioxygenase (IDO), vascular endothelial growth factor (VEGF), matrix metallopeptidase (MMP)-2, MMP-9, and Galectin-1. RESULTS:T-MSCs showed a higher secretion of transforming growth factor beta (TGF-β), prostaglandin E2 (PGE2), IDO, and VEGF and lower secretion of MMP-2 and MMP-9 compared with N-MSCs. However, no significant difference was found in the secretion of interferon gamma (IFN-γ), interleukin 10 (IL10), IL4, IL17, and Galectin-1 in T-MSCs and N-MSCs. The immunomodulatory effect of soluble factors on PBLs showed that T-MSCs, in contrast to N-MSCs, stimulate PBL proliferation. Importantly, the ability of T-MSCs to induce IL10, TGF-β, IFN-γ, and PGE2 was higher than that of N-MSCs. In addition, T-MSCs and N-MSCs exhibited no significant difference in Treg induction. CONCLUSION:MSCs educated in stage II breast cancer and normal breast adipose tissue, although sharing a similar morphology and immunophenotype, exhibited a clearly different profile in some immunomodulatory functions and protein secretions. 10.1007/s00262-020-02567-y