Tumour markers in serous effusions

Evaluation of impact of immunocytochemical techniques in cytological diagnosis of neoplastic effusions

A prospective study (1984-87) on the immunocytochemical identification of cancer cells in effusions using HMFG2 monoclonal antibody, and in addition, monoclonal anti-CEA and B72.3 antibodies in cases of suspected mesothelioma, was undertaken. On the basis of cytology alone, of a total of 2362 pleural, peritoneal, and pericardial effusions, 525 cases were diagnosed as positive and 1485 as negative for neoplastic cells, while in 352 (15%) specimens from 307 patients the diagnosis was doubtful. Sections of the embedded sediment of doubtful cases were tested with HMFG2 antibody and proved positive in 215 cases, negative in 108, and inconclusive in 29. The results were checked by following the clinical outcome of the cases. The method was specific in identifying cancer cells in cases at best diagnosed as suspicious on the basis of cytology alone; this represents a clear diagnostic gain. Sensitivity of the test, however, was relatively low (41%). Combined cytological and immunocytochemical characteristics (CEA negative and only some of the neoplastic cells positive with HMFG2 and B72.3 monoclonal antibodies) permitted diagnosis on the effusions of most cases of mesothelioma. The impact of the diagnosis on the progress of the disease was not appreciable as no difference in outcome was noted, irrespective of whether cancer cells had been recognised. The occurrence of an effusion remains an ominous sign in most patients treated for cancer.

Immunohistological staining of reactive mesothelium, mesothelioma, and lung carcinoma with a panel of monoclonal antibodies

A panel of seven monoclonal antiepithelial antibodies of different specificities, including anticytokeratin, human milk fat globule membrane, C, and carcinoembryonic antigen (CEA) were used with the alkaline phosphatase-antialkaline phosphatase (APAAP) immunostaining technique to determine their value in the differentiation between benign and malignant mesothelial cells and lung carcinoma in histological preparations. The anticytokeratin antibody reacted strongly with all cases of reactive mesothelium, mesothelioma, and lung carcinoma. Antibodies to human milk fat globule membrane and the Ca antigen stained mesothelioma and carcinoma and 43% of cases of reactive mesothelium. Staining for carcinoembryonic antigen was not detected in reactive mesothelium or mesothelioma, but was present in most of the lung carcinomas. CEA seemed to be the single most useful marker in distinguishing carcinoma from mesothelioma in that a positive reaction for CEA would indicate carcinoma rather than mesothelioma.

Ca2 and Ca3. New monoclonal antibodies evaluated as tumor markers in serous effusions

Ca2 and Ca3 are new monoclonal antibodies of IgG1 class, directed against the Ca antigen, a mucus-type glycoprotein expressed on the surface of a wide range of malignant human cells and certain specialized normal epithelia. These antibodies were produced by immunization with purified preparations of the Ca antigen. They were tested to assess their value in the diagnosis of malignant effusions. Immuno-alkaline-phosphatase staining was used. Smears of pleural and peritoneal effusions were chosen to show: undoubted malignant cells of various types; and mesothelial cells in effusions from cases in which cancer was not in question. The Ca2 antibody, at 1 in 20 dilution of the culture supernatant, was the most specific, giving no reactions with benign mesothelial cells from any of the 35 cases tested. Malignant cells were clearly stained in 35 of 40 cases of carcinoma or mesothelioma. The staining was negative in two cases of oat cell bronchial carcinoma, and in three of four cases of carcinoma of the colon. Ca3 gave similar, but somewhat stronger, reactions with carcinoma cells, but was less specific, reacting weakly with mesothelial cells in 8 of 35 benign effusions. Because the false-negative reactions given by the Ca series of antibodies are to some extent complementary to those given by monoclonal antibodies directed against the carcinoembryonic antigen (CEA), a combination of Ca2 and anti-CEA is recommended as a most useful addition to the normal cytologic examination of effusions.

Immunocytochemical reaction of Ca1 and HMFG2 monoclonal antibodies with cells from serous effusions

The Ca1 antibody was used in an alkaline phosphatase immunocytochemical method on cells obtained from 150 specimens of pleural and ascitic fluids. The results were compared with the routine cytology report based on the light microscopical appearances. The Ca1 antibody identified tumour cells in 51 of 57 specimens with malignant cells. The exceptions were four small cell carcinomas, one malignant lymphoma, and one adenocarcinoma. A further seven specimens reported as containing atypical cells but without conclusive evidence of malignancy were Ca1 positive. The Ca1 antibody did not give a positive reaction with benign mesothelial cells. Similar results were obtained with the HMFG2 antibody and malignant cells, but in eight of 18 benign effusions it reacted with mesothelial cells.