In summary, here we have shown that M13MDA435-1 and -3 hybrid cells derived from MDA-MB-435-Hyg human breast cancer cells and M13SV1-EGFP-Neo breast epithelial cells exhibit a differential TLR4 and TLR9 signaling, which is in view with the cell fusion hypothesis that hybrid cells could exhibit novel properties. The gene discussed is TLR9; the disease is breast carcinoma.