Mouse Monoclonal. RTU. Intended for in vitro diagnostic (IVD) use. Anti-TTF-1 (Thyroid Transcription Factor 1) is useful in differentiating primary adenocarcinoma of the lung from metastatic carcinomas originating in the organs rather than thyroid, germ cell tumors, and malignant mesothelioma. It can also be used to differentiate small cell lung carcinoma from lymphoid infiltrates. TTF-1 labeling is also seen in thyroid and thyroid-derived tumors. TTF-1 immunostaining is useful in the differentiation between pulmonary and non-pulmonary origin of adenocarcinomas in malignant effusions. TTF-1 staining is very reliable in discerning whether a brain metastasis has arisen from a pulmonary or non-pulmonary site, particularly when dealing with adenocarcinomas and large-cell carcinomas. References 1. Bejarano PA, et al. Surfactant proteins and thyroid transcription factor-1 in pulmonary and breast carcinomas. Mod Pathol. 1996; 9:445-52. 2. Holzinger A, et al. Monoclonal antibody to thyroid transcription factor-1: production, characterization, and usefulness in tumor diagnosis. Hybridoma. 1996; 15:49-53. 3. Saad RS, et al. Utility of immunohistochemistry in separating thymic neoplasms from germ cell tumors and metastatic lung cancer involving the anterior mediastinum. Appl Immunohistochem Mol Morphol. 2003; 11:107-12. 4. Di Loreto C, et al. TTF-1 protein expression in pleural malignant mesotheliomas and adenocarcinomas of the lung. Cancer Lett. 1998; 124:73-8. 5. Abutaily AS, et al. Immunohistochemistry in the distinction between malignant mesothelioma and pulmonary adenocarcinoma: a critical evaluation of new antibodies. J Clin Pathol. 2002; 55:662-8. 6. Di Loreto C, et al. Immunocytochemical expression of tissue specific transcription factor-1 in lung carcinoma. J Clin Pathol. 1997; 50:30-2. 7. Katoh R, et al. Thyroid transcription factor-1 in normal, hyperplastic, and neoplastic follicular thyroid cells examined by immunohistochemistry and nonradioactive in situ hybridization. Mod Pathol. 2000; 13:570-6. 8. Jang KY, et al. Utility of thyroid transcription factor-1 and cytokeratin 7 and 20 immunostaining in the identification of origin in malignant effusions. Anal Quant Cytol Histol. 2001; 23:400-4. 9. Srodon M, et al. Immunohistochemical staining for thyroid transcription factor-1: a helpful aid in discerning primary site of tumor origin in patients with brain metastases. Hum Pathol. 2002; 33:642-5.