EGFR and Pleural effusion: Three activating EGFR gene mutations were detected in the malignant pleural effusion samples (c.2235_49del15, p.E746_A750del5; c.2573T>G, p.L858R and c.2240_2257del18, p.L747_P753delinsS; 3/36, 8.3%) (Table 2, cases 1–3).