The MDA-MB-231 cell line was selected, because it is representative of the most difficult to treat breast cancer subtype (triple negative breast cancer)38, which is deficient in estrogen, progesterone and ERBB2 (Her2/neu) receptors39, MDA-MB-231 cells are therefore unresponsive to hormone (e.g., Tamoxifen®) or receptor based therapies (e.g., Herceptin®) which are typical used to treat other breast cancer types. The gene discussed is ERBB2; the disease is breast cancer.