Afatinib (Giotrif®, Boehringer Ingelheim Japan, Tokyo, Japan) is one of the second-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs), an orally irreversible ErbB family blocker that covalently binds to the kinase domains of EGFR, human EGFRs (HER)2 and 4, and is clinically effective in non-small cell lung cancer (NSCLC) [1]. Here, ERBB2 is linked to non-small cell lung carcinoma.