Utility of thyroid transcription factor-1 and cytokeratin 7 and 20 immunostaining in the identification of origin in malignant effusions.
OBJECTIVE
To estimate the utility of thyroid transcription factor-1 (TTF-1) and the combined cytokeratin 7 (CK7) and 20 (CK20) immunoprofile as a marker for identifying the primary site of metastatic adenocarcinoma in effusions of the serous cavity.


METHODS
Formalin-fixed, paraffin-embedded cell block specimens of pleural and peritonealfluid diagnosed as metastatic adenocarcinomas with known sites of origin were used for TTF-1, CK7 and CK20 immunohistochemistry. The primary sites of these cases were lung (16 cases), ovary (15), stomach (9), colon (8) and breast (8) and were confirmed by radiologic and/or histologic evaluation.


RESULTS
The lung adenocarcinomas showed TTF-1 positivity in 81% (13/16) of cases. All nonpulmonary adenocarcinomas lacked TTF-1 staining. The CK7-/CK20+ immunophenotype was seen in 63% of colonic adenocarcinomas and not seen in lung, ovary, stomach or breast adenocarcinomas. The CK7+/CK20- immunophenotype was seen in 100%, 88% and 87% of cases that originated in the lung, breast and ovary, respectively.


CONCLUSIONS
TTF-7 immunostaining is useful in the differentiation between pulmonary and nonpulmonary origin of adenocarcinomas in malignant effusions. The combination of CK7-/CK20+ immunostaining is useful in identifying colon adenocarcinomas.
Jang
K Y
KY
Department of Pathology, Chonbuk National University Medical School, Chonju, Republic of Korea.
Kang
M J
MJ
Lee
D G
DG
Chung
M J
MJ
D000230:Adenocarcinoma / Q000175:diagnosis / Q000378:metabolism* / Q000556:secondary; D001202:Ascitic Fluid / Q000175:diagnosis / Q000378:metabolism; D015415:Biomarkers; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D007381:Intermediate Filament Proteins / Q000378:metabolism*; D053554:Keratin-20; D053552:Keratin-7; D007633:Keratins / Q000378:metabolism*; D008297:Male; D009382:Neoplasms, Unknown Primary / Q000175:diagnosis / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D016066:Pleural Effusion, Malignant / Q000175:diagnosis / Q000378:metabolism; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000378:metabolism*
D015415:Biomarkers; D007381:Intermediate Filament Proteins; C507499:KRT20 protein, human; C507497:KRT7 protein, human; D053554:Keratin-20; D053552:Keratin-7; C000614412:NKX2-1 protein, human; D009687:Nuclear Proteins; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; D007633:Keratins