Pathology Outlines

Stains
TTF1

Author: Nat Pernick, M.D.

Topic Completed: 1 June 2005

Revised: 20 January 2020

Copyright: 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: TTF1

Page views in 2019: 23,689

Page views in 2020 to date: 1,657

Table of Contents

Cite this page: Pernick N. TTF1. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/stainsttf1.html. Accessed January 26th, 2020.

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

Contributed by Andrey Bychkov, M.D., Ph.D.

Expression by follicular epithelium

Papillary thyroid carcinoma, TTF1

Lung ADC

Contributed by Carolyn Glass, M.D.

TTF1

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