Monoclonal antibody SM047 as an immunohistochemical marker of ovarian adenocarcinoma

Our plain-English summary of Monoclonal antibody SM047 as an immunohistochemical marker of ovarian adenocarcinoma, by W.G. McCluggage, P. Maxwell, H. Veenstra, et al (Histopathology, 2001).

The study

• Authors: W.G. McCluggage, P. Maxwell, H. Veenstra, C.E. Fick, R.H. Laeng, A.J. Tiltman
• Journal: Histopathology
• Published: 2001;38(6):542-9
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Aims: This study describes the generation of a monoclonal antibody designated SM047 which binds to an epitope that is displayed by a multivalent antigen associated with the glycocalyx of ovarian adenocarcinoma cells. The study also investigates SM047 staining in adenocarcinomas of diverse sites in order to determine whether the antibody is specific for ovarian adenocarcinoma and of value in the confirmation of an ovarian origin when the site of primary tumour is unknown.

Methods And Results: SM047, an IgM monoclonal antibody, was the product of hybridoma cells derived from fusion of SP2 myeloma cells with splenocytes of a mouse that had been immunized with a membrane preparation of tumour (ovarian serous cystadenocarcinoma) and boosted with cells from a cell line established from a similar tumour in a different patient. Sixty-two primary ovarian adenocarcinomas (28 serous, 23 mucinous, five endometrioid and six clear cell), 69 adenocarcinomas arising primary at other sites and 10 mesotheliomas were stained with SM047. There was positive membrane staining, which was usually strong and widespread, in 27 of 28 ovarian serous carcinomas and in all ovarian endometrioid and clear cell carcinomas. Most ovarian mucinous tumours were negative or exhibited weak cytoplasmic staining. Staining was variable in the other tumours but there was positive staining of most endometrial, endocervical and pancreatic adenocarcinomas. Most colonic adenocarcinomas were negative or exhibited weak cytoplasmic staining.

Conclusions: SM047 is strongly expressed in most ovarian serous adenocarcinomas and in other female genital tract adenocarcinomas, with the exception of ovarian mucinous tumours. The antibody may be useful in confirming the ovarian origin of an adenocarcinoma when used as part of a larger panel. This is especially so in the distinction between a non-mucinous ovarian adenocarcinoma, which usually exhibits strong membranous staining, and a colonic adenocarcinoma which is usually negative or exhibits weak cytoplasmic staining. These findings need to be confirmed by further study of larger numbers of cases.

In plain English

This laboratory and pathology study did not examine asbestos exposure. The authors described how they made a mouse antibody called SM047 and tested whether it stains ovarian adenocarcinoma (a cancer of the ovary) and not other tumours. They stained tissue from 62 primary ovarian adenocarcinomas, 69 adenocarcinomas that began at other sites, and 10 mesotheliomas. The article does not say whether the mesotheliomas were pleural or peritoneal. Positive membrane staining, usually strong and widespread, was found in 27 of 28 ovarian serous carcinomas and in all ovarian endometrioid and clear cell carcinomas. In contrast, 16 of 23 ovarian mucinous tumours were completely negative. Staining was not limited to the ovary: all 12 endometrial adenocarcinomas and four of six pancreatic adenocarcinomas stained, while most colonic adenocarcinomas were negative or weakly stained. Four of the 10 mesotheliomas stained, as did normal ovarian surface mesothelium. The antibody's target was also detected in blood from healthy volunteers, at lower readings. The authors concluded that SM047 may help identify where a tumour began when used as part of a larger panel. They said larger studies are needed.

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 study developing a monoclonal antibody, plus an immunohistochemical staining study of tumour specimens
• Who was studied: Surgical tumour specimens: 62 primary ovarian adenocarcinomas (28 serous, 23 mucinous, 5 endometrioid, 6 clear cell), 69 adenocarcinomas arising primarily at other sites, and 10 mesotheliomas. Serum from patients with confirmed or suspected ovarian malignancy (n = 16) and from 7 normal volunteers was also tested. Where and when the specimens were collected is not stated.
• Exposure: No asbestos or other environmental exposure was studied. The specimens were stained with the monoclonal antibody SM047.
• Main results:
  • Positive membrane staining, usually strong and widespread, in 27 of 28 ovarian serous carcinomas and in all ovarian endometrioid (5) and clear cell (6) carcinomas
  • The single negative ovarian serous adenocarcinoma was extremely poorly differentiated
  • 16 of 23 primary ovarian mucinous tumours were completely negative
  • Moderate or strong membranous staining in all 12 endometrial adenocarcinomas (10 endometrioid, 2 papillary serous)
  • Positive staining in some pancreatic (4 of 6), gastric (4 of 9) and lung (1 of 4) adenocarcinomas
  • Most colonic adenocarcinomas were negative or weakly stained in the cytoplasm (Table 1: 15 of 21 colorectal adenocarcinomas negative)
  • 4 of 10 mesotheliomas stained positive, and normal ovarian surface mesothelium stained strongly in the membrane (Table 1: 6 mesotheliomas negative, 2 moderate, 2 strong)
  • The SM047 antigen was also detected in sera from 7 normal volunteers, at lower readings than patient sera
  • The SM047 antigen from pooled normal serum was not sialylated, while that from a patient's serum and from carcinoma cell lysate was
• The authors' conclusion: The authors concluded that SM047, which is not yet commercially available, may prove of value in some circumstances, as part of a larger panel, in determining where an adenocarcinoma originated. Staining was not specific to ovarian tumours.
• Limitations the authors state:
  • The number of non-ovarian adenocarcinomas studied was small, and larger studies are needed
  • SM047 is of no value in distinguishing primary ovarian mucinous adenocarcinoma from metastatic colorectal adenocarcinoma
  • For distinguishing serous adenocarcinoma from mesothelioma, some mesotheliomas and normal mesothelial cells also stain strongly

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: Monoclonal Antibody, Adenocarcinoma, Myeloma, Mesothelioma, Ovarian Serous Carcinoma, Carcinoma.

Related studies

• Value of the MOC-31 monoclonal antibody in differentiating epithelial pleural mesothelioma from lung adenocarcinoma — N.G. Ordóñez (1998)
• Monoclonal antibody HBME-1 reacts with a minor subset of B cells with villous surface and can be useful in the diagnosis of hairy cell leukemia and other indolent lymphoproliferations of villous B lymphocytes — L. Krenács, J. Tóth-Lipták, et al. (2013)
• Immunohistochemical panels for differentiating epithelial malignant mesothelioma from lung adenocarcinoma: a study with logistic regression analysis — R. Carella, G. Deleonardi, et al. (2001)
• OV632 as a possible marker for malignant mesothelioma: high expectations; low specificity — A. Abati, P.A. Fetsch (1995)
• Diagnostic value of monoclonal antibody B72.3 in detecting adenocarcinoma cells in serous effusions — A.F. Lauritzen (1989)
• Calretinin, thrombomodulin, CEA, and CD15: a useful combination of immunohistochemical markers for differentiating pleural epithelial mesothelioma from peripheral pulmonary adenocarcinoma — C.E. Comin, L. Novelli, et al. (2001)

Browse more research in Histopathology, or return to medical research.