Expression of the small cell carcinoma antigens of cluster-5 and cluster-5A in primary lung tumours

Our plain-English summary of Expression of the small cell carcinoma antigens of cluster-5 and cluster-5A in primary lung tumours, by A. Maier, U. Schmidt, R. Waibel, et al (British Journal of Cancer, 1989).

The study

• Authors: A. Maier, U. Schmidt, R. Waibel, W. Hartung, R.A. Stahel
• Journal: British Journal of Cancer
• Published: 1989;59(5):692-5
• Cited by: 11 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The expression of the small cell carcinoma (SCLC) antigens cluster-5 (antibody LAM8) and cluster-5A (antibody SWA20) was examined on a panel of routinely processed biopsy or surgical specimens of 290 lung tumours by immunoperoxidase staining. Antigen expression was largely restricted to SCLC. Of over 150 tissue samples evaluated, moderate or strong antigen expression was found in 49% (cluster-5) and 45% (cluster-5A). Concordance in expression of the two antigens was seen in 71% of SCLC samples, with 35% expressing both antigens strongly, 8% moderately and 28% being negative for both antigens. Antigen expression was independent of the morphological subtype of SCLC. Primary lung tumours of other histology, including squamous cell carcinoma, large cell carcinoma, adenocarcinoma, mesothelioma or carcinoid had no significant antigen expression. Of 135 tumours, strong or moderate expression of both antigens was seen only in two cases. 20%, mostly carcinoids, were weakly positive for cluster 5 and 4% for cluster 5A antigen. The remainder were antigen negative. No significant antigen expression was seen in 25 normal lung tissues. The membrane antigens of SCLC cluster 5 and 5A are markers for SCLC and their expression in tissues is tumour-associated.

In plain English

This pathology study from Ruhr University Bochum, Germany, tested whether antibodies LAM8 and SWA20 stain small cell lung carcinoma (SCLC) in routinely processed tissue. The antibodies detect antigens called cluster-5 (CL-5) and cluster-5A (CL-5A). The authors stained consecutive lung tumour specimens from January 1984 to July 1987 that provided enough tumour material for analysis. These were 155 SCLC, 135 other primary lung tumours (including 10 mesotheliomas) and 25 normal lung samples. The study did not examine asbestos exposure. For CL-5, 26% of SCLC stained strongly, 23% moderately and 30% were negative. For CL-5A, assessed in 152 SCLC (three lacked enough material), 21% stained strongly, 24% moderately and 41% were negative. All 10 mesotheliomas were negative with both antibodies. Of the 135 tumours other than SCLC, only two showed moderate staining: one carcinoid and one biopsy later reclassified as SCLC. Normal lung was largely negative, apart from rare single cells (under 1%) in some bronchial epithelium and occasional bronchial glands. The authors concluded that both antigens are highly restricted to SCLC. They noted that only a proportion of SCLC strongly express them.

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: Immunohistochemical (immunoperoxidase staining) study of consecutive archived lung tumour specimens that provided sufficient tumour material
• Who was studied: Lung tissue from the files of the Institute of Pathology, Ruhr-University of Bochum, FR Germany, January 1984 to July 1987. Only consecutive specimens with sufficient tumour material were included. There were 155 cases of SCLC and 135 other primary lung tumours (25 adenocarcinoma, 10 large cell carcinoma, 40 squamous cell carcinoma, 10 mesothelioma, 50 lung carcinoid), plus 25 normal lung specimens.
• Exposure: No asbestos or other environmental exposure was studied. The tissues were stained with the mouse monoclonal antibodies LAM8 (detecting CL-5) and SWA20 (detecting CL-5A).
• Main results:
  • CL-5 in 155 SCLC tissues: strong expression in 26%, moderate in 23%, weak in 20%, and 30% negative
  • For CL-5A, three SCLC cases could not be evaluated because of insufficient material, leaving 152
  • CL-5A in the 152 evaluable SCLC: 21% strong, 24% moderate, 14% weak, 41% negative
  • The 10 mesotheliomas did not stain with antibody LAM8 (CL-5)
  • In Table II, all 10 mesotheliomas were scored negative for CL-5A with antibody SWA20
  • Only two of the 135 primary lung tumours other than SCLC showed moderate antigen expression
  • Of these two, one was a carcinoid. The other was diagnosed as poorly differentiated squamous cell carcinoma on biopsy and reclassified as SCLC in the resected tissue.
  • In normal lung, bronchial epithelial cells and lung parenchyma were antigen negative, apart from occasional bronchial glands
  • Rare single cells (less than 1%) in some samples of normal bronchial epithelium were antigen positive
  • Among 152 SCLC tissues, CL-5 and CL-5A expression agreed in 108 cases (71%)
  • Antigen expression did not differ between the oat-cell and intermediate morphological subtypes of SCLC
• The authors' conclusion: The authors concluded that the CL-5 and CL-5A antigens are highly restricted to SCLC in vitro and in vivo
• Limitations the authors state:
  • Only a proportion of small cell tumours strongly express the antigens, which the authors said poses some limitations for diagnostic use
  • The reason why antigen expression varies between SCLC tumours had not been determined

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: Carcinoma, Biopsy, Histology, Squamous Cell Carcinoma, Adenocarcinoma, Mesothelioma.

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