EGFR and lung cancer: To evaluate the therapeutic effect of the combination of As2O3 and afatinib in vivo, we performed preclinical tumor models for lung cancer with EGFR mutant in the context of evaluating the add-on effect of As2O3 in afatinib treatment in SCID mice because treatment with As2O3 alone in SCID mice bearing H1975 tumors showed similar results in tumor volume and body weight as control group (Figure S6E-F).