The radioimmunoassay of circulating carcinoembryonic antigen of the human digestive system

Carcinoembryonic antigen and prognosis in patients with colon cancer

One-hundred and fifty patients with non-metastatic colo-rectal cancer were followed for a period of 24 to 36 months postoperatively. Preoperative CEA values have been shown to correlate with the extent of the disease and the patient's prognosis. The prognosis for recurrences is greater in patients with elevated pre-operative CEA values regardless of the stage of their disease. This tendency to have recurrences is 1.8 times higher in individuals with increased pre-operative CEA levels. This same relationship occurs to a greater or lesser extent at each stage of the disease.

Detection of recurrence of large-bowel carcinoma by radioimmunoassay of circulating carcinoembryonic antigen (C.E.A.)

The usefulness and limitations of the carcinoembryonic antigen (C.E.A.) radioimmunoassay for the evaluation of tumour resection and for the detection of tumour relapse were studied in patients with large-bowel carcinoma. The level of plasma-C.E.A. was determined before any treatment in a group of 101 patients with histologically proven adenocarcinoma of the colon and rectum. 71% of all patients and 63% of cases with localised tumour (Dukes A and B) had a preoperative C.E.A. value of 5 ng. per ml. or higher. This limit was reached by only 1 of 90 apparently healthy, non-smoking blood-donors. Among 45 patients for whom a complete tumour resection was reported, all patients except 5 showed a drop of C.E.A. to normal values after surgery. The 5 patients whose C.E.A. did not fall to below 5 ng. per ml. showed a subsequent rise in C.E.A. level and were all found later to have a tumour relapse. The results indicate that an incomplete drop of circulating C.E.A. level one month after surgery has a bad prognostic significance. 22 of these patients were followed up by repeated C.E.A. radioimmunoassay for several months after surgery. 8 showed a progressive increase in C.E.A. levels preceding clinical diagnosis of tumour relapse by two to ten months. 6 other patients showed a moderate increase in C.E.A. levels, suggesting a tumour relapse not yet clinically detectable. The remaining 8 patients showed no increase in C.E.A. level above 5 ng. per ml. and no clinical symptoms of relapse. The results demonstrate that relapses of colon and rectum carcinoma can be detected by increased C.E.A. levels months before the appearance of any clinical evidence.

Serum antibody in patients with breast disease: Correlation with histopathology

Antibody to a breast cancer antigen was detected by immunodiffusion or complement fixation in at least one serum sample in 46% of 84 patients with a diagnosis of carcinoma, 34% of 96 patients with fibrocystic disease and 25% of 44 patients with fibroadenoma. A single serum sample obtained from screenees of the Detection Center for Breast Diseases was tested by immunodiffusion only and antibody was found in 3 of 206 screenees (1.5%). Eleven of 13 patients with breast cancer metastatic to lymph nodes and no detectable serum antibody either had recurrence or were dead within 12 months of mastectomy. Fifteen of 18 patients with breast cancer metastatic to lymph nodes and with detectable serum antibody were alive and free of disease for up to 24 months. Histologic slides from patients with a diagnosis of fibrocystic disease or fibroadenoma were reviewed for the presence of ductal epithelial hyperplasia. Ductal epithelial hyperplasia was present in a similar per cent of patients with no detectable serum antibody as those with antibody detected in the serum. Severe sinus histiocytosis of the axillary lymph nodes was present in 45% of those cancer patients with serum antibody and only 11% of those cancer patients with no detectable serum antibody.

Carcinoembryonic antigen-like substances of human urothelial carcinomas. Isolation of components from pathological urine and comparison with colorectal carcinoma antigens

Urines of several patients with urothelial carcinomas contain inhibitors of the immunoreaction between carcinoembryonic antigen derived from human colorectal carcinomas and monospecific goat antiserum raised against the antigen. These inhibitors range in approximate molecular weights from less than 1000 to several millions, and two have been isolated by a combination of extraction, gel filtration and electrophoretic procedures. These are respectively a macromolecular aggregate, component UCEA-3, which is excluded by Sepharose 4B, and a glycoprotein(s) component, UCEA-1, with mean molecular weight (2x10(5)) similar to that of carcinoembryonic antigen. Comparison of the properties of component UCEA-1 and carcinoembryonic antigen on gel filtration, electrophoresis, immunoelectrophoresis and density gradient ultracentrifugation indicates that these substances of similar molecular size and net charge differ in some immunochemical properties.

Carcinoembryonic antigen and alpha 1-fetoprotein in ulcerative colitis and regional enteritis

Sera were collected from 108 patients with inflammatory bowel disease and assayed for carcinoembryonic antigen (CEA) and alpha(1)-fetoprotein (AFP). Seven (14%) of 51 patients with ulcerative colitis had a positive test for CEA and one of these had associated carcinoma of the colon. Ten (19%) of 52 patients with regional enteritis were also seropositive. The sera of 4 (9%) of 47 patients with ulcerative colitis and 2 (5%) of 41 patients with regional enteritis contained small amounts of AFP. Of two unclassified patients one had a positive CEA and the other a positive AFP. No serum was positive for both CEA and AFP. In addition, multiple samples were available for sequential analysis in eight CEA-positive patients but there was no apparent relationship between seropositivity and disease activity. Continued follow-up is now in progress to determine the significance of detectable fetal antigen levels in inflammatory bowel disease.

Studies of the association of the A, B and Lewis Blood group antigens with carcinoembryonic antigen (CEA)

Carcinoembryonic antigen (CEA) was purified from primary tumour or from hepatic metastases obtained from ten cases of carcinoma of the colon. In nine cases the blood group antigens A, B, Le^a or Le^b were detected in CEA preparations by the binding of ¹²⁵I-labelled CEA by blood group antibodies. The extent of binding appeared to preclude simple contamination of CEA preparations by blood group glycoprotein. In all cases the blood group antigens detected were consistent with the patients' known blood groups. Blood group I and i activities were not detected.

It is concluded that the determinants of A, B and Lewis antigens and of CEA share the same glycoprotein carrier molecules.

Antibody response to different determinants on carcinoembryonic antigen (CEA)

Studies on the diverse nature of the immune response of animals to different antigenic determinants on CEA indicate that the type of antiserum used is of prime importance in determining differences or identities between antigens isolated from tumour and normal tissues. One type of antiserum against CEA shows cross-reactions with a normal colon antigen (NCA) found in both malignant and normal tissues. This finding confirmed that a common determinant is shared by both CEA and NCA. A second type of anti-CEA did not cross react with NCA but reacted only with CEA, providing evidence for a unique CEA determinant. Yet a third and most common type of antiserum to CEA reacted equally well with CEA and NCA and was unable to distinguish between the two. This third type of anti-CEA was completely absorbed with NCA. Failure to recognize this type of anti-CEA would lead to erroneous conclusions regarding the existence of a unique antigenic determinant on CEA.

The effect of serum protein concentrations on the specificity of the radioimmunoassay of carcinoembryonic antigen in malignant neoplasia and non-neoplastic disease

Carcinoembryonic antigen (CEA) has been measured in parallel with seven serum proteins and seromucoids in the sera of patients with malignant neoplasia and non-neoplastic disease. In the total group significant correlations were found between CEA and seromucoids and between CEA and several serum proteins. However, with two exceptions, when the individual disease groups were examined no correlation was seen. It is concluded that abnormal concentrations of the specific proteins measured do not consistently interfere in the CEA radioimmunoassay and do not explain the high CEA levels in patients with non-neoplastic diseases.

Circulating carcinoembryonic antigen (CEA): relationship to clinical status of patients with inflammatory bowel disease

Plasma levels of circulating carcinoembryonic antigen (CEA) were measured by zirconyl phosphate gel radioimmunoassay in 112 patients with chronic inflammatory bowel disease. The levels were then related to category, extent, duration, and severity of disease, as well as to the ages and surgical status of the patients. The distribution of CEA levels and their mean values were significantly raised over the levels in 33 normal control subjects, and were similar among patients with ulcerative colitis compared with those with granulomatous bowel disease. Positive values were defined as those in excess of 2.5 ng/ml. Positive assays occurred in 42% of ulcerative colitis patients, in 38% of Crohn's disease patients, and in 40% of the total group with inflammatory bowel disease. Among normal control subjects, only 3% were positive. Among inflammatory bowel disease patients, positive CEA assays occurred more frequently with more severe disease, more extensive anatomical involvement, younger ages, and shorter duration of disease. Those patients who had undergone total colectomy showed levels of circulating CEA and frequency of CEA positivity similar to those of an age-matched normal control group. Levels of CEA did not correspond with known cancer risk factors in patients with inflammatory bowel disease. Although rising or persisting plasma CEA values unrelated to severity and extent of disease may indicate an unfavourable prognosis in cancer, this study shows that a single CEA value in patients with chronic inflammatory bowel disease is not a reliable indicator of cancer risk.

Radioimmunoassay of tumour specific transplantation antigen of a chemically induced rat sarcoma: circulating soluble tumour antigen in tumour bearers

The tumour specific transplantation antigen (TSTA) from a chemically induced rat sarcoma has been isolated as an electrophoretically homogeneous soluble material by affinity chromatography using a Sepharose bound antibody raised to the tumour in syngeneic rats. The TSTA is specific for the particular tumour used (the MC-1 sarcoma) and does not cross-react with material extracted from other rat sarcomata. In addition, a material with different physicochemical properties which cross-reacted with different sarcomata was also eluted from the antibody column and this may be the previously identified onco-embryonic antigen (OEA1) which is immunogenic in the syngeneic host.The purified TSTA labelled with (125)I was used in a radioimmunoassay which detected soluble TSTA in rats bearing a MC-1 sarcoma. The assay shows that tumour transplantation is associated with a persisting release of soluble antigen into the circulation. This antigenic burden is present continuously and renewed as long as the tumour mass exists.

Serum carcinoembryonic antigen in clinical disorders

Carcinoembryonic antigen (CEA) levels have been measured in the serum of 490 patients and 93 normal controls using the double antibody radioimmunoassay technique. Levels were elevated in 71 of patients with carcinomata of the gastrointestinal tract and in 42% with other types of malignancy. In patients with non-neoplastic disease of the gastrointestinal tract and liver, elevated levels were found in 14 and 66% respectively. In general the CEA level tends to be higher in cancer patients with haematogenous dissemination. Following complete surgical removal of a tumour, levels fall to normal within 14 days in the majority of patients. Of 33 patients studied during follow up, elevated levels were found in 12, 10 of whom had evidence of recurrence. The significance of these findings and the possible application of CEA assay in clinical practice are discussed.