Studies of colonic carcinoma antigens

A thermostable antigen associated with ovarian cancer

Ovarian carcinoma contains an antigen (TA) which is stable at 100 degrees. Rabbit antisera to glycoprotein-rich extracts of tumors detect TA in 70 per cent of ovarian malignancies, in some benign ovarian cysts, certain normal lung preparations, normal cervix, and squamous-cell carcinoma of the cervix. Highest levels may be associated with mucin secretion. No detectible antigen was present in normal ovary, plasma, A, B, and O erythrocytes, leukocytes, placenta, brain, heart, liver, corpus uteri, spleen, skeletal muscle, or kidney. Prolonged digestion of boiled tumor extracts with papain, trypsin, chymotrypsin, on Sephadex G-150 corresponding to a globular protein of 27,000 to 36,000 molecular weight. A beta-globulin mobility is seen in immunoelectrophoresis. It appears that TA differs in tissue specificity and molecular size from other known ovarian cancer associated antigens.

Carcinoembryonic antigen: clinical and historical aspects

To further define and determine the usefulness of CEA, 1100 CEA determinations have been made over the past two years at The Ohio State University Hospitals on patients with a variety of malignant and nonmalignant conditions. Correlation of CEA titers with history and clinical course has yielded interesting results not only in cancers of entodermally derived tissues, for which CEA has become an established adjunct in management, but also in certain other neoplasms and inflammatory states. The current total of 225 preoperative CEA determinations in colorectal carcinomas shows an 81% incidence of elevation, with postoperative titers remaining elevated in patients having only palliative surgery but falling to the negative zone after curative procedures. An excellent correlation exists between CEA levels and grade of tumor (more poorly differentiated tumors showing lower titers). Left-side colon lesions show significantly higher titers than right-side lesions. CEA values have been shown to be elevated in 90% of pancreatic carcinomas studied, in 60% of metastatic breast cancers, and in 35% of other tumors (ovary, head and neck, bladder, kidney, and prostate cancers). CEA levels in 35 ulcerative colitis patients show elevation during exacerbations (51%). During remissions titers fall toward normal, although in 31% still remaining greater than 2.5 ng/ml. In the six colectomies performed, CEA levels all fell into the negative zone postoperatively. Forty percent of adenomatous polyps showed elevated CEA titers (range 2.5-10.0) that dropped following polypectomy to the negative zone. Preoperative and postoperative CEA determinations are important in assessing the effectiveness of surgery. Serial CEA determinations are important in the follow-up period and in evaluation of the other modes of therapy (e.g., chemotherapy). These determinations of tumor antigenicity give the physician added prognostic insight into the behavior of the tumor growth. Rectal examination with guaiac determinations, sigmoidoscopy, cytology, barium enema, and a good clinical evaluation remain the primary tools for detecting colorectal disease. However, in the high-risk patient suspicious of developing cancer, CEA determinations as well as colonoscopy are now being used increasingly and provide additional highly valuable tools in the physician's armamentarium.

[Carcinofetal antigens. III. Further carcinofetal antigens (author's transl)]

The occurrance and significance of important carcinofetal antigens other than AFP and CEA are reported. These included the alpha 2 H-protein which is produced in the liver and increases in serum of patients with various tumors, the fetal sulphoglycoprotein antigen FSA from the gastric juice of patients with gastric cancer, the carcinoplacental alkaline phosphatase (REGAN-isoenzyme)which is found in the serum of patients suffering from e.g. bronchogenic, mammary, urogenital and gastrointestinal carcinomas, the beta-S-fetoprotein which is most likely to be identical with C-reactive protein, gamma-fetoprotein, the carcinofetal antigen in glial tumors (CFGA); ectopic production of placental hormones like human gonadotropin, placental lactogen, plasminogen-activators; leukemia-associated antigens. Furthermore, some other less known carcinofetal antigens are mentioned.

Phytohaemagglutinin-stimulated transformation of peripheral and lymph-node lymphocytes in patients with gastro-intestinal cancer

Phytohaemagglutinin-induced lymphocyte transformation has been studied in 10 patients with gastro-intestinal cancer and in 8 control subjects. When cultured in autologous serum, peripheral lymphocytes from cancer patients exhibited lower transformation indices (L.T.I.) than did those of control subjects. Culture in AB serum resulted in an elevation of the L.T.I. of peripheral lymphocytes from cancer patients whilst those of the controls were essentially unchanged. Of 6 control subjects, 5 showed reduced L.T.I.'s when their circulating lymphocytes were cultured in serum from cancer patients. Mesenteric lymph-node lymphocytes from patients with cancer also showed lower indices compared with the control group and these were elevated by culture in AB serum.

Inhibition of leucocyte migration by tumour-associated antigens of the colon and rectum

The test of leucocyte migration inhibition has been used to detect lymphocyte sensitization to tumour-associated antigens of the colon and rectum. The procedure for the isolation of antigens from colorectal adenocarcinomata and normal colonic mucosa is described. The circulating lymphocytes of 22 patients suffering from colorectal adenocarcinomata of various stages have been examined and compared with the results obtained for identical studies performed on the peripheral lymphocytes of 15 control subjects. Sensitization of lymphocytes to tumour antigen was demonstrated in 15 of the 22 patients when culture was performed in homologous AB serum. Of these 15 patients only six showed inhibition of leucocyte migration in the presence of tumour extract when culture was performed in autologous serum. These observations would suggest the presence of factors in the serum of such patients which may prevent the expression of cellular immunity to tumour antigens.

Immunological study of carcinoembryonic antigen (CEA) and a related glycoprotein

A comparison has been made of the immunological properties of CEA (carcinoembryonic antigen) and another perchloric acid-soluble macromolecule which occurs in colonic and certain other carcinomata and which is here termed CEX. By using a variety of antisera it was shown that the two substances share common antigenic groups as well as having characteristic ones of their own. These latter groups have enabled the preparation of (a) antisera which give a gel diffusion line only with CEA and (b) and antiserum which gives a line only with CEX. No immunological difference could be found between CEX and the NGP of Mach or the NCA of von Kleist and Burtin. CEX was found in foetal gut, in plasma and associated with CEA in virtually all the tissues and fluids in which the latter occurs; the two appear to go hand-in-hand and no proof was found that CEX is either less or more cancer specific than CEA-it is merely found in greater quantity; neither substance showed absolute cancer specificity. The usefulness of a radioimmunoassay for CEX is discussed, and also the possibility of interference by CEX in the radioimmunoassay for CEA. Evidence of two molecular species of CEA has been found.

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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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.

Radioimmunoassay of carcinoembryonic antigen in serum of normal subjects and patients with colonic carcinoma

Sera from 14 normal subjects and 43 patients with colonic carcinoma were evaluated for the presence of carcinoembryonic antigen (CEA). Inhibiting material which behaved in the assay in a similar manner to CEA was found in normal serum at concentrations below 2.8 ng/ml. Its nature has not so far been established. Thirty-eight of the 43 patients with colonic carcinoma showed levels of serum CEA in excess of 2.8 ng/ml. The concentration of CEA in serum was correlated with the extent of the disease as classified by a staging procedure similar to that of Dukes (1932). Examination of a small number of specimens of colonic carcinoma and normal colonic mucosa suggested that the concentration of CEA in different adenocarcinomata may vary, and that traces of cross-reacting material may be found in some normal mucosae.