The radioimmunoassay of circulating carcinoembryonic antigen of the human digestive system

Clinical evaluation of the Makari tumour skin test

A double-blind evaluation of the Makari intradermal test has been carried out over a 3 year period. The test is based upon the measurement of the local erythematous reactions of the skin to a series of intradermal injections of cancer-derived antigens which have been preincubated with the patient's serum. These antigens have been prepared from human tumour material by the application of major physical and chemical degradative procedures. The patients examined consisted of 584 patients referred to King's College Hospital, the majority of whom had signs and symptoms which suggested the presence of malignant disease.

Our studies have confirmed that positive intradermal tests are seen in many but not all patients with malignant tumours arising in different organs, including those of the digestive, respiratory and genitourinary systems. In subjects with carcinoma the response to the test was related to the stage of the carcinomatous process, the largest proportion of positive tests occurring in patients with early disease. An appreciable proportion of positive test results were also observed in diseases associated with inflammatory and reactive processes. In practical terms, therefore, the test is not in its present form suitable for routine cancer screening. However, the relatively high percentage of positive tests in early carcinoma indicates a possible role in monitoring the patient's response to treatment, in detecting the recurrence of tumour at an early stage and in differential diagnosis.

Significance of tumour associated antigens on human colonic carcinomata

A microcytotoxicity assay was used to detect cell mediated immunity against colon and rectum carcinoma cells in vitro. Lymphocytes from 62% of colon carcinoma patients were cytotoxic for the cells, but no cross reactions between colon carcinomata and tumours of other types were observed.

The effect of papain solubilized tumour membrane extracts was evaluated by testing lymphocytes for reactivity following preincubation with the extracts. Soluble preparations of pooled colon carcinomata inhibited cytotoxicity by sensitized lymphocytes, but similar extracts of normal colon or melanoma had no inhibitory effect. The results suggest that soluble tumour antigen may play a role in abolishing lymphocyte reactivity, and this supports the concept that cellular immunity against tumours in vivo may be inhibited by circulating antigen.

Aspects of the structure and clinical role of the carcinoembryonic antigen (CEA) and related macromolecules with particular reference to urothelial carcinoma

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Studies of carcinoembryonic antigen activity of whole and extracted serum in ulcerative colitis

The present study has used a microradioimmunoassay to detect carcinoembryonic antigen(s) (CEA) in whole and extracted serum in 77 patients with ulcerative colitis, two of whom had coexisting colonic carcinoma, and 69 patients with carcinoma of the colon or rectum. Taking 5 ng/ml as the level of positivity, the CEA assay on whole serum showed positive results in patients with ;active' ulcerative colitis (15 of 17) but not in those with ;inactive' disease (0 of 23). In two patients, levels fell during drug-induced remission. Our results also indicated that a positive result for CEA on extracted serum was associated with carcinomatous changes in ulcerative colitis in contrast to uncomplicated ulcerative colitis in which positive results were obtained only with whole serum.

Carcinoembryonic antigen in serum in diseases of the liver and pancreas

Carcinoembryonic antigen (CEA) was measured in whole serum and in serum extracted with perchloric acid by microradioimmunoassay in patients with benign and malignant diseases of the liver and pancreas. The level of detectability was 5 ng per ml. This level or greater was present in the serum of 50% of patients with chronic diffuse liver disease, 64% with pancreatitis, 94% with cancer of the digestive system, and 3% of controls. The incidence of levels of CEA of 5 ng/ml or more differed for various categories of chronic liver disease: from 22% in active chronic hepatitis, 46% in primary biliary cirrhosis, 63% in hepatoma, 78% in cryptogenic cirrhosis, and 88% in alcoholic cirrhosis; levels of CEA correlated with degrees of impairment of liver function as judged by bromsulphalein retention and serum levels of alkaline phosphatase and transaminase. In pancreatitis, 64% of cases had levels of CEA ranging from 5 to 20 ng/ml and in cancer of the pancreas 94% had levels above 5 ng/ml and 50% above 20 ng/ml.

Radioimmunoassay for human alpha 1 -fetoprotein

A method of radioimmunoassay has been developed for the quantitation of alpha(1)-fetoprotein in human serum. The assay requires 20 mul of serum, can be completed in 8 hr, and can reproducibly detect concentrations of 20 ng of alpha(1)-fetoprotein per ml of serum. Hence, the method is about 500-fold more sensitive for the detection of alpha(1)-fetoprotein than the Ouchterlony teohnique currently in general use. The procedure is of potential clinical value as an aid in the diagnosis of cancer and a number of noncancerous hepatic diseases.

A cross-reacting embryonic antigen in the membrane of rat sarcoma cells which is immunogenic in the syngeneic host

An analysis of the constituents of the plasma membrane of a methylcholanthrene-induced sarcoma (the MC1 tumour) in a hooded rat revealed four tumour-associated macromolecules. Two of these were antigenic in the syngeneic host, one was unique to the MC1 tumour and could not be detected in embryo tissue and has the properties to be expected from the well established tumour-specific transplantation-type antigen while the other, referred to as OEA I, was present in all rat sarcomata tested as well as in early embryos. Two other embryonic components were detected in the sarcoma but these were not immunogenic in the rat. The properties of these tumour-associated "antigens" in the membrane of rat sarcomata are summarized below: [Table: see text]

The presence of tumour-specific membrane antigen in the serum of rats with chemically induced sarcomata

Antibodies to the tumour-specific transplantation type antigen (TSTA) of a transplanted methylcholanthrene-induced sarcoma (MC-1) in syngeneic rats were studied using the techniques of indirect membrane immunofluorescence and mixed haemadsorption with a (51)Cr-labelled indicator cell. After tumour excision, anti-TSTA antibody was readily measurable in both serum and lymph. In contrast, the tumour-bearing animal had no measurable anti-TSTA antibody in the serum but low titres in the lymph. Consequently, we formed the hypothesis that in the presence of a growing tumour the serum contained antigen-antibody complexes with antigen in excess.To test this hypothesis, tumour-bearing serum was examined for the presence of free antigen and antigen-antibody complexes by 2 different methods. In the first method, tumour-bearing serum was cross-linked with glutaraldehyde and was found to absorb specifically the anti-TSTA antibody, indicating free circulating TSTA. Next, antigen-antibody complexes were split with salt or acid and separated into a low molecular weight (or "antigen") fraction (<100,000) and a high molecular weight (or "antibody") fraction (>100,000). The low M.W. fraction specifically inhibited the anti-TSTA antibody when tested by either membrane immunofluorescence or mixed haemadsorption, indicating the presence of antigen from antigen-antibody complexes in the tumour-bearing circulation. The possible effect on the host's immune response of circulating free tumour antigen and antigen-antibody complexes are discussed.

Carcinoembryonic antigen in whole serum

A microradioimmunoassay technique is described for detecting carcinoembryonic antigen (CEA) in whole serum. It differs from previous methods in being performed on 0·025 ml of whole serum instead of 5 ml of serum extracted with perchloric acid. The present assay was sufficiently sensitive to detect 85% of carcinomata, localized to the colon, but positive results occurred also with certain non-gastrointestinal cancers, chiefly lung and breast, and certain non-malignant diseases. Many of the latter sera, with the general exception of alcoholic cirrhosis and pancreatitis, gave negative results after extraction with perchloric acid. It is suggested that a direct assay for CEA in whole serum may permit testing of large numbers of sera by laboratories with facilities for radioimmunoassays.

Role of plasma carcinoembryonic antigen in diagnosis of gastrointestinal, mammary, and bronchial carcinoma

Our studies have confirmed that raised plasma levels of carcinoembryonic antigen (C.E.A.) occur with many but not all malignant tumours, particularly those of the gastrointestinal tract, breast, and bronchus. However, the incidence of raised values may reach 30% in diseases associated with inflammation or regeneration or both. Consequently, it cannot serve yet as a routine screening test for cancer. Effective surgical therapy results in high plasma C.E.A. levels returning to normal. Subsequent rises appear to develop with tumour recurrence or spread. At present the most useful role for C.E.A. seems to be in monitoring patients during the post-therapeutic followup period. Further basic work is required before C.E.A. can become of routine medical value.

Separation of skin reactive intestinal cancer antigen from the carcinoembryonic antigen of Gold

Soluble fractions of human intestinal cancer and fetal intestinal cell membranes produced delayed hypersensitivity reactions in patients with intestinal cancer. These soluble fractions and perchloric acid extracts of intestinal cancer cells were fractionated by polacrylamide-gel electrophoresis. The Gold carcinoembryonic antigen was found in a region of the gels different from that of the skin reactive antigen.

Identification of an antigen from normal human tissue that crossreacts with the carcinoembryonic antigen

A glycoprotein present in normal human tissue is characterized that is neither organ- nor tumor-specific (nonspecific crossreacting antigen) and that crossreacts (by the Ouchterlony double-diffusion technique) with the carcinoembryonic antigen. This immunological relationship indicates common determinants on the molecules of both antigens. We demonstrate that the nonspecific crossreacting antigen is not a fragment of the carcinoembryonic antigen molecule.

Early detection and mass screening for cancer

The author reviews the evidence for the efficacy of early detection and mass screening programs in reducing morbidity and mortality from cancer. In cancer of the cervix, although screening reduces morbidity, we still do not have evidence for reduction in mortality. In cancer of the breast, one study suggests a reduction in mortality in the 50-59 year age group following screening by clinical examination and mammography. In other sites, especially lung, there is no evidence at present to support the adoption of mass screening programs. It is important that such programs should be carefully evaluated in the population, preferably in controlled studies.

A collaborative study of a test for carcinoembryonic antigen (CEA) in the sera of patients with carcinoma of the colon and rectum. A joint National Cancer Institute of Canada-American Cancer Society investigation

Five university centres in Canada and the United States have collaborated in a study of a test for carcinoembryonic antigen, with the Montreal General Hospital laboratory acting as the reference laboratory, examining duplicate halves of specimens from patients examined in local laboratories.Between June 1971 and April 1972, 503 patients were admitted to the study, 146 with cancer of the colon or rectum. Discrimination between colo-rectal cancer and "other" diagnoses was good at 2.5 ng./ml. or more, such a result being obtained in 66% of the patients with colo-rectal cancer in the local laboratories and 62% in the reference laboratory compared with 39% and 33% respectively of patients with "other" diagnoses. Patients with Duke's C lesions of the colon or rectum were more likely to have raised CEA levels than patients with more localized lesions. CEA was also more commonly found in patients with other cancers and in patients with liver disease than in patients with other (benign) diagnoses.It is concluded that the test can be reproduced in other laboratories and that it or another simplified technique could become an important diagnostic aid for colo-rectal cancer.