TTF1 and mesothelioma: The European Society of Thoracic Surgeons recommended that mesothelioma be diagnosed by a panel and including a combination of immunohistochemical positive and negative markers; tumor cells in malignant mesothelioma have been reported to be positive for calretinin, vimentim, keratin and epithelial membrane antigen (EMA), while the markers for adenocarcinoma, CEA and thyroid transcription factor 1 (TTF-1) were negative (13).