Skin rash and diarrhea are the most frequent ADRs in patients receiving EGFR TKIs, and several meta-analyses have reported a significantly higher risk of skin rash with afatinib (84.8%) than with erlotinib (62.0%) or gefitinib (62.0%) (p < 0.01) [17, 22]. The gene discussed is EGFR; the disease is Skin rash.