A significant breakthrough in the field of research was the identification of microRNAs (miRNAs), which are small molecule, single-stranded nucleic acids. MiRNAs have diverse roles in cellular biology with the ability for translation in different areas of medicine. The size of miRNAs provides them for passage through gap junction. Recent studies have demonstrated the passage of miRNAs through gap junctional intercellular communication (GJIC) among cancer cells and between breast cancer cells and bone marrow stroma. The transfer of miRNAs has been implicated in the etiology of breast cancer dormancy. To this end, we have developed a miRNA reporter assay to assess the ability of miRNAs to be transferred between stem and breast cancer cells and target a specific recognition sequence.