Keratin proteins and carcinoembryonic antigen in lung carcinoma: an immunoperoxidase study of fifty-four cases, with ultrastructural correlations

Our plain-English summary of Keratin proteins and carcinoembryonic antigen in lung carcinoma: an immunoperoxidase study of fifty-four cases, with ultrastructural correlations, by J.W. Said, G. Nash, G. Tepper, et al (Human Pathology, 1983).

The study

• Authors: J.W. Said, G. Nash, G. Tepper, S. Banks-Schlegel
• Journal: Human Pathology
• Published: 1983;14(1):70-6
• Cited by: 154 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

This study evaluates the use of immunoperoxidase stains for keratin and carcinoembryonic antigen (CEA) in the diagnosis of lung cancer. Immunohistochemical staining for these antigens was performed on paraffin sections from 54 lung neoplasms, and the results were correlated with the histologic, histochemical, and ultrastructural appearances of the tumors. Strong staining for keratin proteins was evident in all squamous cell carcinomas. This reaction was particularly helpful in identifying squamous differentiation in poorly differentiated areas and in cases in which tonofilaments appeared to be sparse or absent on electron microscopy. Weak focal staining for keratin was evident in only two cases of adenocarcinoma, and the difference in frequency of staining between squamous cell carcinomas and adenocarcinomas was statistically significant (P = 0.01). Carcinoembryonic antigen was variably present in all types of lung carcinoma, but staining for it was strongly positive in cases of adenocarcinoma. Positive staining for keratin with negative or focal weak staining for CEA was characteristic of mesotheliomas, which was helpful in differentiating them from adenocarcinomas. When evaluated by multiple means including immunohistochemical analysis, tumors with mixed differentiation were frequently identified and most large cell carcinomas showed evidence of glandular or squamous differentiation. Electron microscopic demonstration of neurosecretory granules was the best single diagnostic criterion for small cell anaplastic carcinomas (P = 0.01, as determined by stepwise logistic regression analysis). Also helpful in differentiating between small and large cell anaplastic carcinomas were a significantly smaller mean cell diameter in the former, as measured on electron micrographs (P = 0.05), and positive staining for keratin, which occurred significantly more often in large cell carcinomas (P = 0.03). These findings suggest that immunoperoxidase stains for keratin and CEA supplement routine histochemical and electron microscopic studies in the diagnosis of lung tumors, and may provide additional specific objective criteria for their classification.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This was a laboratory pathology study from Cedars-Sinai Medical Center in Los Angeles and the National Cancer Institute. It examined tissue from 54 lung tumors held in surgical pathology files, including eight cases of malignant mesothelioma. It did not study asbestos or any other exposure. The authors stained the tissue for keratin proteins and carcinoembryonic antigen (CEA) and compared the results with routine stains and electron microscopy. All eight squamous cell carcinomas and all eight mesotheliomas stained strongly for keratin. Only two of six adenocarcinomas showed weak, focal keratin staining. Keratin staining was significantly more frequent in mesothelioma than in adenocarcinoma (P = 0.01). All six adenocarcinomas stained strongly for CEA, while the mesotheliomas were negative or, in two cases, showed focal faint staining. Neurosecretory granules seen by electron microscopy were the best single diagnostic sign of small cell anaplastic carcinoma (P = 0.01). The authors concluded that these stains supplement routine tests in diagnosing lung carcinoma and may provide objective criteria for classifying lung tumors.

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 pathology study (immunoperoxidase staining of archived tumor tissue, correlated with histochemistry and electron microscopy)
• Who was studied: 54 lung tumors from the surgical pathology files of Cedars-Sinai Medical Center, Los Angeles: 8 squamous cell carcinomas, 6 adenocarcinomas, 12 small cell anaplastic carcinomas, 13 large cell undifferentiated carcinomas (including 3 giant cell carcinomas), 3 adenosquamous carcinomas, 4 carcinoid tumors and 8 malignant mesotheliomas. Seven of the eight mesotheliomas were diagnosed on pleural or chest wall biopsy. Dates of the cases are not given.
• Exposure: No asbestos or other exposure was studied. The article concerns laboratory staining for keratin proteins and carcinoembryonic antigen (CEA) in tumor tissue.
• Main results:
  • All eight squamous cell carcinomas stained strongly for keratin (focally in one case).
  • Only two of six adenocarcinomas showed keratin staining, and it was focal and weak.
  • All eight malignant mesotheliomas showed strong keratin staining in the cell cytoplasm.
  • Keratin staining occurred significantly more often in mesothelioma than in adenocarcinoma (P = 0.01).
  • Mesotheliomas were negative for CEA or showed focal faint staining (two cases). All six adenocarcinomas stained strongly for CEA.
  • All six adenocarcinomas showed strong CEA staining, the most consistent CEA staining of any tumor type.
  • The three mesotheliomas examined by electron microscopy had long, sometimes branching surface microvillous processes.
  • Neurosecretory granules seen on electron microscopy were the best single diagnostic criterion for small cell anaplastic carcinoma (P = 0.01, stepwise logistic regression).
  • Small cell anaplastic carcinoma cells had significantly smaller mean cell diameters than large cell undifferentiated and squamous cell carcinoma cells (P = 0.05).
  • Keratin staining occurred significantly more often in large cell carcinoma than in small cell anaplastic carcinoma (P = 0.03).
  • No test showed a significant difference between adenocarcinoma and large cell carcinoma.
• The authors' conclusion: The authors concluded that immunoperoxidase stains for keratin and CEA supplement routine histochemical and electron microscopic studies in diagnosing lung carcinoma, and may provide specific objective criteria for classifying lung tumors.
• Limitations the authors state:
  • The authors noted that there were too few cases to tell whether CEA staining reliably distinguishes small cell carcinoma from carcinoid tumors.
  • The authors noted that electron microscopy suffers from sampling error. Tissue for electron microscopy was not available for five of the eight mesotheliomas.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer.

Medical terms in this study, explained in our Lexicon: Carcinoembryonic Antigen (CEA), Carcinoma, Lung Cancer, Immunohistochemistry, Neoplasm, Squamous Cell Carcinoma, Adenocarcinoma, Mesothelioma.

Related studies

• Immunoperoxidase localization of keratin proteins, carcinoembryonic antigen, and factor VIII in adenomatoid tumors: evidence for a mesothelial derivation — J.W. Said, G. Nash, et al. (1982)
• The distinction of adenocarcinoma from malignant mesothelioma in cell blocks of effusions: the role of routine mucin histochemistry and immunohistochemical assessment of carcinoembryonic antigen, keratin proteins, epithelial membrane antigen, and milk fat globule-derived antigen — E.S. Cibas, J.M. Corson, et al. (1987)
• Use of antibodies to carcinoembryonic antigen and human milk fat globule to distinguish carcinoma, mesothelioma, and reactive mesothelium — R.J. Marshall, A. Herbert, et al. (1984)
• Keratin protein immunoreactivity of sarcomatoid and mixed types of diffuse malignant mesothelioma: an immunoperoxidase study of 30 cases — A.G. Montag, G.S. Pinkus, et al. (1988)
• Lung surfactant protein-A and carcinoembryonic antigen in pleural effusions due to lung adenocarcinoma and malignant mesothelioma — N. Shijubo, Y. Honda, et al. (1995)
• Distinct keratin patterns demonstrated by immunoperoxidase staining of adenocarcinomas, carcinoids, and mesotheliomas using polyclonal and monoclonal anti-keratin antibodies — H.J. Kahn, P.S. Thorner, et al. (1986)

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