Although the detection of p.T790M in EGFR-mutant NSCLC patients can be performed on both plasma and tumor tissue, the evolution of diagnostic approaches towards minimally-invasive procedures such as cftDNA is desirable for a number of reasons, including a) the invasive character of a tissue biopsy, b) unreachable tumor sites or insufficient tissue obtained after biopsy [26] and c) limitation of tissue biopsy in capturing tumor heterogeneity due to the small amount of tissue collected and number of tumor sites sampled. Here, EGFR is linked to neoplasm.