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Table of Contents
Definition / general | Uses by pathologists | Microscopic (histologic) images | Positive staining - normal | Positive staining - disease | Negative stainingCite this page: Pernick N. TTF1. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/stainsttf1.html. Accessed April 24th, 2019.
Definition / general
- Thyroid transcription factor, also called thyroid specific enhancer binding protein
- 38 kDa nuclear protein that regulates transcription activity of thyroid (thyroglobulin, thyroperoxidase, sodium-iodide transport protein, calcitonin and MHC class I), lung (surfactant proteins A, B and C, Clara cell secretory protein) and diencephalon specific genes
- Mutations cause pulmonary hypoplasia and neonatal death
- Specificity depends on antibody clone used
- Interpretation: nuclear stain
Uses by pathologists
- Distinguish primary (TTF1+) vs. metastatic (usually TTF1-) lung carcinoma
- Distinguish pulmonary adenocarcinoma (TTF1+) from squamous cell carcinoma (usually TTF1-)
- Pleural lung carcinoma (TTF1+) vs. mesothelioma (TTF1-)
- Pulmonary small cell carcinoma (TTF1+) vs. Merkel cell carcinoma (TTF1-)
Microscopic (histologic) images
Images hosted on PathOut server:
Contributed by Andrey Bychkov, M.D., Ph.D.:
Expression by follicular epithelium
Papillary thyroid carcinoma, TTF1
Images hosted on other servers:
Pulmonary adenocarcinoma
metastasis (left) to
renal cell carcinoma (right)
CK7 (2A); TTF1+ (2B); RCC (2C)
Positive staining - normal
- Lung type II pneumocytes and Clara cells; thyroid follicular and parafollicular C cells
Positive staining - disease
- Lung carcinoma: small cell (90%), adenocarcinoma (75%); large cell (40%); squamous cell (5%, Am J Surg Pathol 2001;25:363)
- Thyroid: hyperplastic and neoplastic thyroid tissue, but less common / lower levels in undifferentiated thyroid carcinomas (Mod Pathol 2000;13:570)
- Other tumors: small cell carcinomas of lung and various sites (Mod Pathol 2000;13:238; Am J Surg Pathol 2001;25:815); colorectal carcinomas to lung may be positive (Mod Pathol 2005;18:1371), small cell carcinoma of bladder (39%, Hum Pathol 2005;36:718)
Negative staining
- Merkel cell carcinoma of skin, most nonpulmonary non-small cell carcinomas
