This work is a study of mediators and mechanisms of the effect of human mesenchymal stem cells from bone marrow (hMSC BM) on the tumor cell population line MCF-7 (breast adenocarcinoma). It is known that MSCs produce a wide range of cytokines and chemokines, and provide humoral cells interaction. BM MSCs produce tumor necrosis factor (TNF-α), interleukin (IL-1β, IL-2, IL-4, IL-6, IL-8), interferon-alpha (IFN-α). In this study we compared the proliferation, adhesion, survival and antigenic profile of breast adenocarcinoma cells that were cultured with conditioned medium (с-medium) of the MSC and IFN-α. Consequently, it was found that с-medium from MSC inhibited proliferation activity of MCF-7, increased cells adhesion, suppressed the ability to migrate, and reduced the expression of estrogen receptor and epidermal growth factor receptor. Conversely expression of cytokeratins increased, which is a positive sign for the tumor cells of epithelial origin. IFN-α showed a more pronounced effect on the tumor population. These findings suggest that cryopreserved MSC BM has antitumor activity. Also, our data suggest that IFN-alpha is one of the mediators of antitumor effect of MSCs.