Aggressive cancer cells have similar characteristics to embryonic stem cells (ESCs). Some of thesecommon characteristics are self-renewal, differentiation to multipotent lineage cells, geneexpression signature and plasticity, and consequently engaging in a dynamic reciprocity with theirmicroenvironment. However, ESCs have microenvironment which regulates balance of self-renewaland differentiation. In contrast, cancer cells have uncontrolled proliferation potential. Based onthe aberrant and deregulated expression of embryonic genes in tumor cells, there is an openquestion whether these cells can respond to regulatory cues controlling self-renewal pathwayswhich might be sent from microenvironment of ESCs; And as a result whether tumorigenicphenotype of cancer cells can be supressed. Pervious works have reported that the exposure ofaggressive cancer cell line to human ESCs (hESCs)-conditioned matrix or medium, inducesreprogramming of aggressive cancer cells to normal differentiated phenotype that has lessaggressive state and less proliferation potential. This suggests a potential ability of pluripotentstem cell-conditioned medium as a cell-free therapeutic approach. The purification of conditionedmedium has since revealed that ESCs release small molecules, including cytokines, chemokines,growth factors and also a large quantity of extracellular vesicles which can exert paracrine effect oncells. The current study has focused on effects of hESCs-derived extracellular vesicles as bioproductof hESCs-conditioned medium on proliferation, differentiation and aggressive properties of cancercells. At first, we extracted extracellular vesicles from hESCs and characterized them. In the nextstep, we exposed the breast cancer cell lines to hESCs-derived exosomes. It is observed that thetreatment of exosome on aggressive breast cancer cell line reduced the proliferation,colonogeneity, and sphere formation of breast cancer cells. This findings suggest thatmicroenvironment of human embryonic stem cells has the potential to modulate stemness propertyof aggressive cancer cells and limit the proliferation of this cells.