In a study, about 12% of NSCLC patients resistant to EGFR TKIs were found to have HER2 amplification, whereas the incidence of HER2 amplification in untreated NSCLC patients was only 1%, suggesting that HER2 amplification may be involved in the resistance process to EGFR TKIs. Here, EGFR is linked to non-small cell lung carcinoma.