For example, micelles prepared with d-α-tocopheryl polyethylene glycol succinate linked to a siRNA that inhibits polo-like kinase 1 (shows a pivotal role in cell mitosis) and conjugated with trastuzumab (anti-HER-2 monoclonal antibody), were loaded with docetaxel and demonstrated a significantly higher cytotoxic effect in HER-2-positive breast cancer cells (SK-BR-3 cells) than non-conjugated micelles, with IC50 values of around 3.2 and 0.67 ng/mL, respectively. The gene discussed is ERBB2; the disease is breast cancer.