The aptamer-doxorubicin complex (Apt-DOX) was formulated by intercalating Dox into the DNA structure of HB5 and managed to selectively deliver DOX to HER2-positive breast cancer cells while reducing the drug intake by HER2-negative cells in vitro with reduced cytotoxicity to HER2-negative cells [136]. The gene discussed is ERBB2; the disease is breast cancer.