To test whether an active IFN-γ signaling pathway in MDA-MB-231 breast cancer cells would be crucial for their successful passage across the in vitro BBB, we impaired the IFN-γ pathway in breast cancer cells by either blocking the IFN-γ receptor on the MDA-MB-231 breast cancer cells, or by neutralizing the sIFN-γ in the CM of activated T lymphocytes. This evidence concerns the gene IFNG and breast cancer.