Wang S, Chen H, Zhong J, et al. - Researchers conducted this investigation to compare malignant pleural effusion (MPE), plasma and tumor tissues as sources of biological samples for EGFR mutational analysis of patients with adenocarcinoma of the lung. From lung adenocarcinoma patients, a total of 295 MPE samples have been retrospectively obtained. With Denaturing high performance liquid chromatography (DHPLC), EGFR exon-19-deletion and exon 21-L858R mutation have been identified. Data reported that the EGFR mutation rate in MPE samples was 39.3%. The authors concluded that MPE is a reliable surrogate for the identification of EGFR mutations in tumor tissue. In advanced lung adenocarcinoma patients even when tissue and plasma were available, MPE could offer a reference of EGFR mutation to EGFR-TKIs treatment decision.