The reproducible resistance mechanism observed in MIA PaCa-2 cells (Fig. 4e) was distinct from KRAS-mutant colon and lung cancer models, which evidenced neither ABCG2 upregulation (Supplementary Fig. 4d) nor resensitization to ERK inhibition by pharmacologic ABCG2 inhibition (Supplementary Fig. 4e). The gene discussed is ABCG2; the disease is lung cancer.