Monoclonal-antibody-defined human lung tumour cell-surface antigens

Immunohistochemical Evaluation of a Panel of Monoclonal Antibodies for the Diagnosis of Small Cell Lung Cancer

Monoclonal antibodies (mAbs) with a high sensitivity and specificity for small cell lung cancer (SCLC) may be of potential diagnostic and therapeutic use. We selected five different mAbs generated against SCLC cell lines and tested them on paraffin-embedded SCLC and non SCLC (NSCLC) clinical samples in a retrospective study using immunohistochemical techniques. The results showed that the contemporary use of mAbs that react with different antigens allowed all the examined SCLC to be detected indicating that this panel of mAbs was extremely sensitive. Analysis of the reactivity of these mAbs with NSCLC showed that 4 of the 5 antibodies reacted also with a few NSCLC. Using higher dilutions of these mAbs their specificity improved substantially. The 5 different mAbs presented marked heterogeneity of antigenic expression within and between SCLC. This panel of antibodies may be very useful in the diagnosis of SCLC whereas their application, in vivo, in therapeutic trials, is limited by the heterogeneity of antigenic expression.

Monoclonal antibodies for the in vitro detection of small cell lung cancer metastases in human bone marrow

Three rat monoclonal antibodies were selected for the immunodetection of small cell lung cancer metastases in bone marrow and other hematologic samples. By membrane immunofluorescence, they define three distinct surface antigens here termed lung cancer-associated antigens or LCAs. The latter are widely expressed on small cell lung cancer and non-small cell lung cancer cells/cell lines, but not detectable on a variety of normal and transformed bone marrow, blood and lymphoid cells. Anti-LCA1 (IgM) is similar to the many anti-lacto-N-fucopentaose III IgM antibodies rasied against human tumors. In contrast, anti-LCA2 (IgG2b) and anti-LCA3 (IgG2a) define surface proteins of 29, 32, 41 and 98 kilodaltons, respectively, that have not been reported earlier. These three reagents have immunodiagnostic potential, since in combination they label all 49 lung cancer cell lines tested. Their ability to detect lung cancer metastases in patient's bone marrow samples is documented in an accompanying paper.

Epithelium-specific surface glycoprotein of Mr 34,000 is a widely distributed human carcinoma marker

An epithelial cell surface antigen is described which is defined by monoclonal antibody HEA125 (IgG1). The antibody was raised against the colon carcinoma cell line HT-29. Under reducing conditions HEA125 immunoprecipitates a surface glycoprotein of Mr 34,000 which was designated Egp34. The antigen does not contain disulfide-linked subunits. A slightly different migration behavior under non-reducing conditions (Mr 39,000) may be due to intrachain disulfide bonds. After enzymatic cleavage of N-linked carbohydrate residues the apparent molecular weight of the antigen was 29,000. Egp34 is a major cell surface component of HT-29 cells (10(6) molecules per cell). No antigen could be detected in the sera of colorectal cancer patients. A panel of malignant cell lines and normal cells was studied for surface expression of the antigen. 17/17 carcinoma lines of 6 different origins expressed the antigen, whereas 16/16 melanoma, neuroblastoma, sarcoma and lymphoma/leukaemia were unreactive as it was the case for normal fibroblasts and blood cells. Immunoperoxidase staining of frozen tissue sections with HEA125 demonstrated the presence of Egp34 in almost all normal epithelia and tumours derived therefrom. No reactivity with non-epithelial tissues was observed. Undifferentiated carcinomas of various origins homogeneously expressed Egp34. Therefore, HEA125 may become a valuable tool for the immunohistochemical diagnosis of carcinoma.

Biological, pathological and clinical features of small cell lung cancer

Small cell lung cancer, which is not uncommon, and is one of the most malignant and relatively well investigated solid tumors of adults, has been reviewed concerning its biology, pathology and clinical aspects. Although it is histologically very simple, its poorly differentiated epithelial cell characteristics are complicated by features of neuroendocrine cells, such as amine and peptide hormone production and specific enzyme activities, some of which have been found to be good monitoring markers during and after treatment. Because of the relative ease of establishing cell lines in vitro, cell characteristics have been studied in detail. This has led to subtyping of cell lines and may further lead to subtyping of histology. However, accumulation of further evidence has disclosed exceptions and unclassifiable cell lines. The same can be said about chromosomal abnormality. The reactivity of monoclonal antibodies and also oncogenes supports the prevalent concept discriminating small cell cancer from non-small cell cancer. However, concepts concerning histogenesis are still changing. Although it is one of the solid tumors most sensitive to radiation and chemotherapy, the response rate of the tumor to non-surgical treatment appears to have reached a plateau. In order to make a breakthrough in the treatment, strategies based on biological findings must be applied.

Establishment and characterisation of cell lines from patients with lung cancer (predominantly small cell carcinoma)

Tissue samples from 59 patients with lung cancer have been used to establish cell lines in culture. The primary diagnosis was small cell carcinoma in all except four. Most of the samples were of bone marrow but pleural effusions, lymph node biopsies and skin metastases were also included. The samples were usually split between HITES serum-free medium and HITES plus 2.5% foetal calf serum. A total of 19 cell lines were established and characterised. One line is large cell anaplastic lung carcinoma, four are B-lymphoblastoid and fourteen are small cell lung cancer. Considerable heterogeneity in gross morphology, neuroendocrine differentiation (by electron microscopy) and content of the enzyme L-dopa decarboxylase was seen. The use of HITES plus 2.5% foetal calf serum resulted in better establishment of cultures than did serum-free HITES.