Three types of EGFR inhibitors are currently used in the cancer field: first-generation reversible small-molecule inhibitors that target EGFR and coreceptor HER2 (erlotinib and gefitinib), second-generation inhibitors that irreversibly bind to EGFR (afatinib, dacomitinib, and neratinib), and third-generation irreversible TKIs (AZD9291). Here, EGFR is linked to cancer.