title: Thyroid transcription factor-1 distinguishes metastatic pulmonary from well-differentiated neuroendocrine tumors of other sites.
abstract: Metastatic neuroendocrine neoplasms can have similar histologic appearances, and without an obvious primary, it may be difficult to determine the site of origin of the metastasis. Thyroid transcription factor-1 (TTF-1) is a nuclear protein expressed during the development of thyroid, lung, and forebrain. The clinical utility of TTF-1 to distinguishing between metastatic pulmonary and nonpulmonary well-differentiated neuroendocrine tumors (WDNET) has not been previously studied. One hundred fifty-eight primary and metastatic WDNET were evaluated for TTF-1 expression. The tumors included 20 pulmonary WDNET, including 17 typical and 3 atypical carcinoid tumors, 10 metastatic pulmonary WDNET, 26 intestinal WDNET, 24 metastatic intestinal WDNET, 3 thymic mediastinal WDNET, 30 thyroid tumors (10 medullary carcinomas, 5 follicular carcinomas, 5 follicular adenomas, 5 papillary carcinomas, and 5 anaplastic carcinomas), 10 parathyroid adenomas, 20 pituitary adenomas, 10 pancreatic WDNET, and 5 pheochromocytomas. TTF-1 expression was found in 19 of 20 (95%) pulmonary WDNET, 8 of 10 (80%) metastatic pulmonary WDNET, and in 0 of 50 (0%) intestinal WDNET. All thyroid tumors were diffusely positive for TTF-1, except for three anaplastic carcinomas. All parathyroid and pituitary adenomas, pancreatic and thymic WDNET, and pheochromocytomas were uniformly negative for TTF-1. These results indicate that TTF-1 is clinically useful in distinguishing metastatic pulmonary from metastatic WDNET of extrapulmonary origin.
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Oliveira
authors.forename: H D
authors.initials: HD
authors.lastname: Tazelaar
authors.forename: J L
authors.initials: JL
authors.lastname: Myers
authors.forename: L A
authors.initials: LA
authors.lastname: Erickson
authors.forename: R V
authors.initials: RV
authors.lastname: Lloyd
mesh_terms: D003937:Diagnosis, Differential; D006801:Humans; D008175:Lung Neoplasms / Q000737:chemistry* / Q000473:pathology*; D018358:Neuroendocrine Tumors / Q000737:chemistry* / Q000473:pathology / Q000556:secondary*; D009687:Nuclear Proteins / Q000032:analysis*; D013961:Thyroid Gland; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000032:analysis*
chemical_list: C000614412:NKX2-1 protein, human; D009687:Nuclear Proteins; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors