Given this perspective, resistant forms of breast cancer that over-expresses EGFR and HER2/neu are often less vulnerable to the cytotoxic potency of chemotherapeutics due to a simultaneous over-expression of trans-membrane P-glycoprotein which functions as a somewhat non-selective membrane “pump” complex for many pharmaceutical agents [109-114]. The gene discussed is ABCB1; the disease is breast carcinoma.