The advanced NSCLC adenocarcinoma is the best example for the liquid biopsy application in molecular cancer profiling at the time of diagnosis [such as EGFR, ALK, c-ros oncogene 1 (ROS1), v-raf murine sarcoma viral oncogene homolog B1 (BRAF), MET, rearranged during transfection (RET) analysis)], when the tissue is insufficient for the molecular testing (about 50% of the cases) [181, 229] and a new tissue biopsy cannot be performed, or at the time of progressive disease after a targeted therapy with tyrosine kinase inhibitors (TKIs) [200, 201, 230]. Here, EGFR is linked to cancer.