J Korean Med Sci.  2002 Aug;17(4):512-517. 10.3346/jkms.2002.17.4.512.

Utility of Thyroid Transcription Factor-1 and Cytokeratin 20 in Identifying the Origin of Metastatic Carcinomas of Cervical Lymph Nodes

• Roh MS
• Hong SH

• KMID: 1109761
• DOI: http://doi.org/10.3346/jkms.2002.17.4.512

Abstract

The identification of primary location of a metastatic tumor is a difficult diagnostic problem and sometimes can be facilitated by the use of immunohistochemical markers. Thyroid transcription factor-1 (TTF-1) is a 38-kDa nuclear homeodomain transcription factor that is expressed specifically in lung or thyroid neoplasms. Cytokeratin 20 (CK20) is a 46-kDa low-molecular-weight cytokeratin that shows restricted expression in adenocarcinomas of the gastrointestinal tract (GIT) and transitional cell carcinomas of the urinary tract. We studied the immunohistochemical expression of TTF-1 and CK20 in 68 metastatic carcinomas in cervical lymph nodes. The primary sites were the lung in 29 cases, stomach in 13, colorectum in 3, and other sites in 23. TTF-1 expression was detected in 69.0% of metastatic lung carcinomas and none in metastatic GIT carcinomas, whereas CK20 expression was detected in 68.8% of metastatic GIT carcinomas and none of metastatic lung carcinomas. TTF-1 had a specificity of 0.95 and a sensitivity of 0.69 for metastatic lung carcinoma, whereas CK20 had a specificity of 1.00 and a sensitivity of 0.69 for metastatic GIT carcinoma. These results indicate that TTF-1 and CK20 should be the first choice as a component of antibody panel to prove or to exclude the lung and GIT origin, respectively, especially in patients presenting with metastatic carcinomas of unknown primary site.

Keyword

Thyroid Transcription Factors; Cytokeratin 20; Neoplasms Metastasis; Lymph Nodes; Cervical

MeSH Terms

Adenocarcinoma/chemistry/pathology/secondary
Carcinoma/chemistry/pathology/*secondary
Gastrointestinal Neoplasms/chemistry/pathology
Homeodomain Proteins/analysis
Humans
Intermediate Filament Proteins/*analysis/immunology
Keratin-20
Lung Neoplasms/chemistry/pathology
Lymph Nodes/chemistry/pathology
Lymphatic Metastasis/*diagnosis/pathology
Neck
Neoplasms, Unknown Primary/chemistry/pathology
Nuclear Proteins/*analysis/immunology
Sensitivity and Specificity
Transcription Factors/*analysis/immunology
Tumor Markers, Biological/analysis