A post-hoc analysis of the multicentric, open-label, randomized, phase III ENSURE study, that evaluated the efficacy and safety of erlotinib versus gemcitabine plus cisplatin as first-line treatment for stage IIIB/IV EGFRmut NSCLC patients [12] showed a 76.7% of agreement between EGFR testing for exon 19 deletion and exon 21 (L858R) mutation in plasma using the Cobas EGFR Mutation Test v2 (Roche Molecular Systems, Inc.)and standard EGFR testing in tissue. Here, EGFR is linked to non-small cell lung carcinoma.