Keratins 7 and 20 as diagnostic markers of carcinomas metastatic to the ovary

Our plain-English summary of Keratins 7 and 20 as diagnostic markers of carcinomas metastatic to the ovary, by C.C. Wauters, F. Smedts, L.G. Gerrits, et al (Human Pathology, 1995).

The study

• Authors: C.C. Wauters, F. Smedts, L.G. Gerrits, F.T. Bosman, F.C. Ramaekers
• Journal: Human Pathology
• Published: 1995;26(8):852-5
• Cited by: 168 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The most common carcinomas metastatic to the ovary that mimic ovarian primaries are colonic adenocarcinomas and endometrial carcinomas. Conventional histochemical staining procedures, even in combination with additional immunohistochemical assays, are of limited value in distinguishing between these metastases and primary ovarian carcinomas. In this study we investigated whether the application of monoclonal antibodies against keratins 7, 8, and 20 could help in differentiating between these categories. The reactivity patterns of 40 carcinomas metastatic to the ovary were compared with those of their primary carcinomas on the one hand and with various primary ovarian carcinomas and mesotheliomas on the other. Colon cancer metastatic to the ovary was keratin 7 negative and keratin 20 positive in 94% of the cases; in contrast, all primary ovarian carcinomas were keratin 7 positive and keratin 20 negative, with the exception of two cases of mucinous cystadenocarcinoma. Ovarian metastases of gastric cancer usually contained keratins 7 and 20. Metastases of endometrial cancer to the ovary and primary ovarian carcinomas usually showed similar keratin expression. We propose that keratin 7 and 20 antibodies may be of help to distinguish between primary ovarian carcinomas and carcinoma metastases in the ovary.

In plain English

This Dutch laboratory study tested whether staining for keratins 7, 8 and 20 could help pathologists tell cancers that began in the ovary from cancers that spread there. The authors used archived tissue from four pathology departments. It included ovarian metastases from colon, stomach, breast and endometrial cancers, most matching original tumors, primary ovarian carcinomas, and five mesotheliomas. Keratin 8 was found in all lesions. Of 16 colon cancer metastases, 14 stained extensively for keratin 20, and four stained for keratin 7. Keratin 20 was not detected in the mesotheliomas. In mucinous ovarian carcinomas, keratin 20 varied: three of five were negative and two showed some staining, unlike other primary ovarian carcinomas, which were keratin 20-negative. All gastric and breast metastases contained keratin 7, and nine of 10 endometrial metastases stained extensively for it. The authors concluded that differences in keratins 7 and 20 were helpful in separating primary ovarian carcinomas from gastrointestinal cancers spread to the ovary. They stated that lacking keratin 20 distinguishes mesotheliomas from gastric and colon cancer metastases. The study did not examine asbestos exposure.

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 comparing keratin staining patterns
• Who was studied: Archived paraffin tissue from pathology departments in Rotterdam, Delft, Gouda and Nijmegen, the Netherlands. Per the article's table: ovarian metastases of colonic (17, including one appendix), gastric (4), breast (9) and endometrial (10) carcinomas; primary colonic (15), gastric (4), breast (6) and endometrial (10) carcinomas; primary ovarian serous (5), mucinous (5) and poorly differentiated (5) carcinomas; and 5 mesotheliomas (site not stated)
• Exposure: No asbestos or other environmental exposure was studied. The tissues were stained with monoclonal antibodies against keratin 7 (OV-TL 12/30), keratin 8 (CAM 5.2, used as positive control) and keratin 20 (IT-Ks 20.8)
• Main results:
  • Keratin 8 staining was present in all lesions.
  • Keratin 7 was found in primary ovarian adenocarcinomas and mesotheliomas, mostly extensively, but the text also states that two tumors were negative.
  • Keratin 20 was not detected in the mesotheliomas.
  • Mucinous ovarian carcinomas varied for keratin 20: three were negative, and one of the remaining two stained in more than 50% of tumor cells.
  • The two mucinous carcinomas with some keratin 20 staining were the exception to the keratin 20-negative pattern the authors observed in the other primary ovarian carcinomas.
  • Among colon carcinoma metastases to the ovary, keratin 7 staining was found in 4 of 16.
  • Among colon carcinoma metastases to the ovary, 14 of 16 showed extensive keratin 20 staining.
  • All ovarian metastases of gastric cancer contained keratin 7-positive cells. Both keratins 7 and 20 were expressed in gastric metastases, so the difference from primary ovarian carcinomas was less distinct.
  • Among the 9 breast cancer metastases to the ovary, all were keratin 7-positive. Keratin 20 was negative in eight, and scattered cells were positive in the other.
  • Among metastatic endometrial adenocarcinomas, 9 of 10 showed extensive keratin 7 staining, and one was negative.
  • The authors stated that the lack of keratin 20 in mesotheliomas distinguishes them from metastases of gastric and colon cancer.
• The authors' conclusion: The authors concluded that differences in keratin 7 and 20 expression were helpful in distinguishing primary ovarian carcinomas from gastrointestinal adenocarcinomas metastatic to the ovary.
• Limitations the authors state:
  • Staining occasionally differed between a primary tumor and its metastasis. The authors suggested technical factors such as tissue processing might be responsible.

Topics

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

Medical terms in this study, explained in our Lexicon: Carcinoma, Adenocarcinoma, Monoclonal Antibody, Mesothelioma, Colorectal Cancer, Stomach Cancer.

Related studies

• Cytokeratin 7 and cytokeratin 20 expression in epithelial neoplasms: a survey of 435 cases — P. Chu, E. Wu, et al. (2000)
• Combined use of novel epithelial (MOC-31) and mesothelial (HBME-1) immunohistochemical markers for optimal first line diagnostic distinction between mesothelioma and metastatic carcinoma in pleura — C. González-Lois, C. Ballestín, et al. (2001)
• Utility of cytokeratin 20 in identifying the origin of metastatic carcinomas in effusions — V. Ascoli, S. Taccogna, et al. (1995)
• Use of intermediate filament antibodies in the differential diagnosis of gynecological neoplasia — F.C. Ramaekers, J.J. Puts, et al. (1985)
• Value of mesothelial and epithelial antibodies in distinguishing diffuse peritoneal mesothelioma in females from serous papillary carcinoma of the ovary and peritoneum — R.L. Attanoos, R. Webb, et al. (2002)
• 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)

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