TTF1 and lung cancer: In general, EpCAM (epithelial cell adhesion molecule, BerEP4) (Fig 2B) and Calretinin (Fig 2C) were used as pan-epithelial and mesothelial markers, respectively, and if necessary, additional tumor specific markers were analyzed, such as TTF1 (thyroid transcription factor 1) (Fig 2E) in effusions originating from lung cancer patients.