The most frequent were TP53-mutations found in 67% of these cases, whereas 60% of them harbored co-mutations in either MET, KRAS, SMAD4, PIK3CA, CTNNB1, NRAS, DDR2, ERBB4, FGFR1, or FGFR3. Using the same targeted NGS platform as ours, two other groups recently detected cases of advanced EGFR-mutant NSCLC that prior to gefitinib-treatment displayed co-mutations very similar to those identified in our study and at comparable frequency. The gene discussed is NRAS; the disease is non-small cell lung carcinoma.