DARWIN I study (NCT02183883), which involves patients registered to TRACERx study, will assess if targeting EGFR and HER2 mutations by afatinib in NSCLC is more effective when these mutations are truncal dominant mutations (≥ 50%), as opposed to non-dominant (≥ 5 to < 50%) or low-frequency mutations (< 5%) [79]. This evidence concerns the gene ERBB2 and non-small cell lung carcinoma.