The distribution of vimentin and keratin in epithelial and nonepithelial neoplasms. A comprehensive immunohistochemical study on formalin- and alcohol-fixed tumors

Our plain-English summary of The distribution of vimentin and keratin in epithelial and nonepithelial neoplasms. A comprehensive immunohistochemical study on formalin- and alcohol-fixed tumors, by N. Azumi, H. Battifora (American Journal of Clinical Pathology, 1987).

The study

• Authors: N. Azumi, H. Battifora
• Journal: American Journal of Clinical Pathology
• Published: 1987;88(3):286-96
• Cited by: 341 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Vimentin has been regarded as the intermediate filament characteristic of normal and neoplastic mesenchymal cells and keratins as typical of epithelial cells and the neoplasms derived from them. However, many epithelial cells in tissue culture or in effusion, as well as cells in some solid epithelial neoplasms such as renal, endometrial, ovarian, pulmonary, and thyroid adenocarcinomas, have been shown to coexpress vimentin and keratin. The recent availability of monoclonal antibodies that work reasonably well in paraffin-embedded tissue led us to carry out a comprehensive immunohistochemical study on formalin- and alcohol-fixed specimens of neoplasms in which we used monoclonal antibodies against vimentin. These results were compared with our previous study in which the same tumor tissues were investigated using antibodies against keratin. The antigenicity of vimentin was found to be preserved in all alcohol-fixed specimens and in 63% of formalin-fixed tissues. Vimentin was the sole intermediate filament present in virtually all sarcomas, meningiomas, schwannomas, and melanomas. In addition, variable percentages (10-57%) of carcinomas, neuroendocrine carcinomas, neuroblastomas, thymomas, and mesotheliomas were positive for vimentin, which, except in the neuroblastomas, was coexpressed with keratins. Among the adenocarcinomas, more than 50% of papillary carcinomas of the thyroid, as well as renal, endometrial, ovarian, and lung carcinomas, coexpressed keratins and vimentin. A distinctive paranuclear and basal localization of vimentin was observed in the cells of many of these tumors, in contrast to the predominantly apical distribution of the keratins. The authors conclude that coexpression of vimentin and keratin is more widespread than previously reported and that antibodies to vimentin, by themselves, are of limited value for the differentiation of epithelial from mesenchymal neoplasms.

In plain English

This laboratory study from City of Hope National Medical Center, California, did not examine asbestos exposure; it tested tumor staining for vimentin, a cell-skeleton protein, as a diagnostic aid. The authors stained 825 tumor samples (544 formalin-fixed, 281 alcohol-fixed) for vimentin and compared results with their earlier keratin study. After excluding 22 hard-to-interpret samples and 194 formalin-fixed samples that had lost vimentin staining, 336 formalin-fixed and 273 alcohol-fixed samples remained. Detection sensitivity was 0.57 in formalin-fixed tumors versus 1.00 in alcohol-fixed tissue. Virtually all melanomas and schwannomas, and all alcohol-fixed sarcomas, were vimentin positive. So were all alcohol-fixed renal cell and papillary thyroid carcinomas, and 12 of 27 lung adenocarcinomas. The text reports three of five formalin-fixed mesotheliomas as vimentin positive, but Table 2 lists three of eight. Two positive ones were mainly sarcomatous, with most positive cells in the sarcomatous parts. The authors concluded that vimentin antibodies have some diagnostic limitations but may help in antibody panels on well-fixed samples. They noted that formalin-fixed material alone could make up to 40% of cases look falsely negative.

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 immunohistochemical study of archived tumor specimens and normal autopsy tissue, compared with the authors' previous keratin study on the same tissues
• Who was studied: 825 samples of malignant and benign epithelial and nonepithelial tumors (including sarcomas, melanomas, mesotheliomas, germ cell tumors, meningiomas and lymphomas) from the surgical pathology files of City of Hope National Medical Center, Duarte, California, and from one author's consultation files. 544 were formalin fixed and 281 alcohol fixed, and both kinds of sample were available for 248 cases. Collection dates are not stated.
• Exposure: No asbestos or other environmental exposure was studied. The tissues were stained with two mouse monoclonal antibodies against vimentin (DAKO and Enzo) and compared with staining for low-molecular-weight keratins.
• Main results:
  • Two groups of samples were excluded. 22 were removed because nonneoplastic vimentin-positive cells or too few tumor cells made them hard to interpret. 194 formalin-fixed samples were removed because their built-in control tissues failed to stain (fixation-induced loss of antigen). That left 609 samples: 336 formalin-fixed and 273 alcohol-fixed. The article prints these as 63% of 544 and 98% of 281, which do not match the counts.
  • Using alcohol-fixed tissue as the standard, the sensitivity of vimentin detection in formalin-fixed tumor tissue was 0.57, versus 1.00 for alcohol-fixed tissue.
  • Virtually all melanomas and schwannomas were strongly vimentin positive.
  • Sarcomas: 100% of alcohol-fixed samples were vimentin positive, compared with 85% of formalin-fixed samples.
  • Vimentin was found in all alcohol-fixed renal cell carcinomas and papillary thyroid carcinomas, and in 12 of 27 pulmonary adenocarcinoma samples.
  • Vimentin positivity was also found in five (12%) breast adenocarcinomas.
  • Mesotheliomas: the text reports three of five formalin-fixed mesotheliomas as vimentin positive. Table 2, however, lists 3 positive and 5 negative formalin-fixed mesotheliomas, 8 in total.
  • Two of the three vimentin-positive mesotheliomas were predominantly sarcomatous, with most positive cells in the sarcomatous portions. Focal positivity of the epithelial components was noted in one mesothelioma.
• The authors' conclusion: The authors concluded that their findings suggest some limitations of antivimentin antibodies as diagnostic tools. However, used together with other antibodies in panels, especially on optimally fixed samples, these antibodies may help establish or confirm a tumor's diagnosis or subclassification.
• Limitations the authors state:
  • Formalin fixation reduces vimentin detection. If only formalin-fixed material is examined, up to 40% of cases may be wrongly read as negative.
  • The study contained no adrenocortical carcinomas.

Topics

Medical terms in this study, explained in our Lexicon: Neoplasm, Adenocarcinoma, Monoclonal, Sarcoma, Carcinoma, Mesothelioma.

Related studies

• Immunohistochemical staining for vimentin and keratin in malignant mesothelioma — A. Churg (1985)
• Expression of calretinin, thrombomodulin, keratin 5, and mesothelin in lung carcinomas of different types: an immunohistochemical analysis of 596 tumors in comparison with epithelioid mesotheliomas of the pleura — M. Miettinen, M. Sarlomo-Rikala (2003)
• Unusual primary lung neoplasms: spindle cell and undifferentiated lung carcinomas expressing only vimentin — S.P. Hammar, K.O. Hallman (1990)
• Cytokeratin 7 and cytokeratin 20 expression in epithelial neoplasms: a survey of 435 cases — P. Chu, E. Wu, et al. (2000)
• The applicability of a keratin 7 monoclonal antibody in routinely Papanicolaou-stained cytologic specimens for the differential diagnosis of carcinomas — J.H. Baars, J.L. De Ruijter, et al. (1994)
• Differential expression of N-cadherin in pleural mesotheliomas and E-cadherin in lung adenocarcinomas in formalin-fixed, paraffin-embedded tissues — A.C. Han, A. Peralta-Soler, et al. (1997)

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