Expression of cytokeratins 7 and 20 in carcinomas of the extrahepatic biliary tract, pancreas, and gallbladder.
BACKGROUND
Expression of cytokeratins 7 (CK7) and 20 (CK20) may help distinguish the site of origin for metastatic carcinomas. Little is known regarding their expression in biliary tract and pancreatic carcinomas. Our aim was to study the expression of CK7 and CK20 in these tumors.


METHODS
Fifty-three carcinomas of the extrahepatic bile ducts (n = 8), ampulla of Vater (n = 7), gallbladder (n = 11), and pancreas (n = 27), were retrieved from the surgical pathology files of the University of Massachusetts Medical Center. Formalin-fixed, paraffin-embedded sections were immunostained with mouse monoclonal antibodies to CK7 and CK20 using an avidin-biotin immunoperoxidase technique with microwave antigen retrieval. The percentage of cells positive for each antibody was assessed on a scale of 0 to 3 (0, <10%; 1+, 10% to 50%; 2+, 51% to 90%; 3+, >90%).


RESULTS
The majority of carcinomas in all groups were positive for CK7 (CK7+) and negative for CK20 (CK20-). Of the CK7+ tumors, the majority of tumors in each group were 3+ positive.


CONCLUSIONS
(1) Carcinomas of the extrahepatic biliary tract and pancreas are strongly positive for CK7 and negative for CK20 and can be included in the differential diagnosis of other carcinomas with this profile in metastatic sites. (2) The CK7/CK20 immunostaining profile will not identify the site of origin for tumors with extensive growth in the porta hepatis region.
Department of Pathology, UMass Memorial Health Care, Worcester, MA 01655, USA.
J V
JV
Duval
L
L
Savas
B F
BF
Banner
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000378:metabolism* / Q000473:pathology; D017734:Bile Ducts, Extrahepatic / Q000473:pathology*; D002277:Carcinoma / Q000378:metabolism* / Q000473:pathology / Q000556:secondary; D003937:Diagnosis, Differential; D005260:Female; D005706:Gallbladder Neoplasms / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007381:Intermediate Filament Proteins / Q000096:biosynthesis*; D053554:Keratin-20; D053552:Keratin-7; D007633:Keratins / Q000096:biosynthesis*; D008113:Liver Neoplasms / Q000175:diagnosis / Q000556:secondary; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology
D007381:Intermediate Filament Proteins; C507499:KRT20 protein, human; C507497:KRT7 protein, human; D053554:Keratin-20; D053552:Keratin-7; C489975:Krt20 protein, mouse; C507496:Krt7 protein, mouse; D007633:Keratins