Cytokeratin 5/6 immunostaining in hepatobiliary and pancreatic neoplasms

Our plain-English summary of Cytokeratin 5/6 immunostaining in hepatobiliary and pancreatic neoplasms, by D.M. Vlasoff, D.Y. Baschinsky, W.L. Frankel (Applied Immunohistochemistry & Molecular Morphology, 2002).

The study

• Authors: D.M. Vlasoff, D.Y. Baschinsky, W.L. Frankel
• Journal: Applied Immunohistochemistry & Molecular Morphology
• Published: 2002;10(2):147-51
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Immunohistochemistry with different cytokeratin subsets has been successfully used in the differential diagnosis of various human epithelial neoplasms. Cytokeratin 5/6 antibody, which recently became commercially available, has been found useful in the diagnosis of mesothelioma. Studies have reported only infrequent staining in adenocarcinomas. We investigated the pattern of immunoreactivity for cytokeratin 5/6 in hepatobiliary and pancreatic tumors to determine its diagnostic utility in the morphologic evaluation of these neoplasms. Formalin-fixed. paraffin-embedded tissue sections from 10 hepatocellular carcinomas, seven hepatocellular adenomas, 10 cholangiocarcinomas, 10 pancreatic ductal adenocarcinomas, and 13 pancreatic neuroendocrine carcinomas were immunostained with anticytokeratin 5/6 after heat-induced antigen retrieval utilizing a modified avidin-biotin complex technique. Positive and negative controls stained appropriately. Two pathologists evaluated the slides. Strong but focal cytoplasmic immunoreactivity was observed in five of 10 pancreatic ductal adenocarcinomas and two of 10 cholangiocarcinomas. No immunoreactivity was identified in any cases of hepatocellular carcinoma (0/10), hepatocellular adenoma (0/7), or pancreatic neuroendocrine carcinoma (0/13). Additionally, occasional cytokeratin 5/6 immunoreactive benign ductal epithelial cells were seen in the background in some cases. Fifty percent of pancreatic ductal adenocarcinomas and 20% of cholangiocarcinomas are positive with anti-cytokeratin 5/6 immunostaining. For the evaluation of poorly differentiated neoplasms in the liver, immunoreactivity with cytokeratin 5/6 may help to exclude the possibility of hepatocellular carcinoma. Cytokeratin 5/6 may be helpful as a component in the panel of immunostains to differentiate between poorly differentiated neoplasms.

In plain English

This laboratory study did not examine asbestos exposure or mesothelioma. It tested whether a staining method, an antibody against cytokeratin 5/6, could help pathologists tell apart tumors of the liver, bile ducts and pancreas. The authors noted that other researchers had found this antibody useful in diagnosing mesothelioma. They stained 50 archived tumor tissue blocks from The Ohio State University: 10 hepatocellular carcinomas, seven hepatocellular adenomas, 10 cholangiocarcinomas, 10 pancreatic ductal adenocarcinomas and 13 pancreatic neuroendocrine carcinomas. Staining was found in five of 10 pancreatic ductal adenocarcinomas and two of 10 cholangiocarcinomas. None of the other tumors stained. Where staining occurred it was very focal, covering 1% to 10% of cells. The authors concluded that cytokeratin 5/6 is of limited value for separating these tumors, though positive staining in a liver tumor excludes hepatocellular carcinoma. They stated that their sample was too small to separate cholangiocarcinoma from pancreatic ductal adenocarcinoma, and that all their cases were large surgical specimens, so the focal staining could be missed in small needle biopsies.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory immunohistochemistry study of archived tumor tissue
• Who was studied: 50 archived tumor tissue blocks: 10 hepatocellular carcinomas, seven hepatocellular adenomas, 10 cholangiocarcinomas, 10 pancreatic ductal adenocarcinomas and 13 pancreatic neuroendocrine carcinomas, from The Ohio State University
• Exposure: None; the study did not examine asbestos or any other exposure. It tested staining of tumor tissue with an antibody against cytokeratin 5/6.
• Main results:
  • Strong but focal staining was seen in five of 10 pancreatic ductal adenocarcinomas and two of 10 cholangiocarcinomas
  • No staining was seen in hepatocellular carcinoma (0/10), hepatocellular adenoma (0/7) or pancreatic neuroendocrine carcinoma (0/13)
  • Tumors that stained did not differ from those that did not stain in histologic grade or stage
  • In all stained cases the staining was very focal, involving between 1% and 10% of cells
  • Individual benign (non-cancerous) duct lining cells in the background also stained in some cases
• The authors' conclusion: The authors concluded that cytokeratin 5/6 can be of limited value for distinguishing hepatobiliary and pancreatic tumors. In their view, positive staining of a liver tumor excludes hepatocellular carcinoma, and the antibody may help in selected cases alongside other stains.
• Limitations the authors state:
  • The sample was too small to draw conclusions about distinguishing cholangiocarcinoma from pancreatic ductal adenocarcinoma
  • All cases were large surgical resection specimens. In small needle biopsies the very focal staining could be underestimated.

Topics

Medical terms in this study, explained in our Lexicon: Cytokeratin 5/6, Neoplasm, Immunohistochemistry, Differential Diagnosis, Mesothelioma, Adenocarcinoma, Carcinoma.

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