Original contributionTTF-1 expression is specific for lung primary in typical and atypical carcinoids: TTF-1-positive carcinoids are predominantly in peripheral location
Section snippets
Case selection and classification
All pulmonary and extrapulmonary NETs (excluding small cell carcinomas) were identified from the surgical pathology files during the period of 1994 to 2002 at UCSD Medical Center, San Diego, CA. Additional cases of pulmonary and thymic NETs were contributed from Royal Brompton Hospital, London, UK, which included the cases during the period from 1982 to 1999. Each case was re-examined to confirm the diagnosis and cases with sufficient amount of tumor in the paraffin block for study were
TTF-1 expression
TTF-1 positivity was seen exclusively in pulmonary NETs. All thymic and abdominal/pelvic NETs were negative for TTF-1 (both TTF-I and TTF-E scores 0). Intensity and extent scores of each category and demographic details are summarized in Table 1. TTF-1 positivity was significantly higher in TL (72.7%) than in TC (27.8%), AC (29.4%), and LCNEC (37.5%; P = 0.03), but there was no significant difference among the TC, AC, and LCNEC cases (P = 0.66; Fig 1). Strong immunoreactivity, as in positive
Discussion
This study evaluates TTF-1 expression across a spectrum of pulmonary NETs, with the purposes of documenting prevalence in a series of neoplasms less well described than more common types of pulmonary neoplasm, comparing prevalence with extrapulmonary counterparts and assessing any differences across the spectrum of pulmonary NETs. To date, data on TTF-1 expression in TCs show considerable variation,11, 14, 16, 17, 18, 19, 20 and there are few data on TTF-1 expression in extrapulmonary ACs and
Acknowledgements
The authors thank Mr. Steven Claunch and Mrs. Wilma Flordeliza for their outstanding immunohistochemical staining and Dr. Unyoung Goh for her skilled statistical analysis.
References (34)
- et al.
Expression of thyroid transcription factor-1 (TTF-1) in human C cells and medullary carcinomas
Hum Pathol
(2000) - et al.
Expression of thyroid transcription factor-1 in normal and neoplastic lung tissues
Mod Pathol
(2002) - et al.
Utility of surfactant protein B precursor and thyroid transcription factor 1 in differentiating adenocarcinoma of the lung from malignant mesothelioma
Hum Pathol
(1999) - et al.
TTF-1 expression in human lung tumours
Eur J Cancer
(1996) - et al.
Thyroid transcription factor-1 is expressed in extrapulmonary small cell carcinomas but not in other extrapulmonary neuroendocrine tumors
Mod Pathol
(2000) - et al.
Cytokeratin 7 and 20 and thyroid transcription factor 1 can help distinguish pulmonary from gastrointestinal carcinoid and pancreatic endocrine tumors
Hum Pathol
(2001) - et al.
Expression of thyroid transcription factor-1 in the spectrum of neuroendocrine cell lung proliferations with special interest in carcinoids
Hum Pathol
(2002) - et al.
On the origin of the so-called tumorlets of the lung
Hum Pathol
(1976) - et al.
The role of electron microscopy in the diagnosis of unusual peripheral lung tumors
Hum Pathol
(1978) - et al.
A thyroid-specific nuclear protein essential for tissue-specific expression of the thyroglobulin promoter
EMBO J
(1989)