To demonstrate that the conjugate can selectively target HER2 overexpressing cancer cells, we decided to use a broad spectrum of cell lines, including MDA-MB-453 cells expressing high levels of HER2 (HER2+), T-47D expressing slightly elevated levels of HER2 (HER2+/−), and cell lines expressing low levels of HER2 (HER2−), including U-87 MG, SK-MES-1, and MDA-MB-231. The gene discussed is ERBB2; the disease is cancer.