An increase in Ref-1/APE1 expression in NSCLC confers resistance to cisplatin treatment, while Ref-1/APE1 siRNA knockdown in A549 cancer cells significantly enhances cisplatin cytotoxicity.202 Patients with tumors not expressing Ref-1/APE1 respond better to platinum-paclitaxel therapy203 and cisplatin-docetaxel-gemcitabine treatment,81 with longer time to progression and overall survival. This evidence concerns the gene APEX1 and cancer.