CEACAM5 and Pleural effusion: The study by Porcel et al, which analysed 416 patients with pleural effusion, obtained a sensitivity of 54% through the combination of four TMs (CA15.3, CA19.9, CA125 and CYFRA 21–1) [20]; the work by Gaspar et al, which included 155 patients, achieved a sensitivity of 75% through the combination of three TMs (CEA, CA15.3 and TAG-72) [21]; and the meta-analysis by Yang et al, which analysed combinations of pleural fluid TMs for the diagnosis of MPE in 20 studies, obtained a sensitivity of 64% through the combination of CEA+CA15.3 and of 58% with CEA+CA19.9 [22].