EGFR and lung adenocarcinoma: Pérez-Barrios Pérez-Barrios C C Sánchez-Herrero Sánchez-Herrero E E Garcia-Simón Garcia-Simón N N Barquín Barquín M M Clemente Clemente MB MB Provencio Provencio M M ctDNA from body fluids is an adequate source for EGFR biomarker testing in advanced lung adenocarcinoma ctDNA from body fluids is an adequate source for EGFR biomarker testing in advanced lung adenocarcinoma Clin Chem Lab Med Clin Chem Lab Med 2021 2021 59 59 1221 1221 9 9 10.1515/cclm-2020-1465 10.1515/cclm-2020-1465 33691348 33691348