Carcinoembryonic antigen (CEA) in feces and plasma of normal subjects and patients with colorectal carcinoma

Superiority of fecal carcinoembryonic antigen as diagnosis marker for adenomatous polyposis coli and asymptomatic colorectal cancer

BACKGROUND

Non-invasive diagnostic tools of adenomatous polyposis coli (APC) and asymptomatic colorectal cancer (CRC) are urgently needed. Although fecal carcinoembryonic antigen (FCEA) has been documented in some studies, the diagnostic potential for the detection of APC and asymptomatic CRC has not been described yet.

METHODS

This is a retrospective study. The pre-diagnostic serum carcinoembryonic antigen (SCEA) and fecal occult blood test (FOBT) levels were retrospectively analyzed in 212 patients with intestinal diseases group (IDG) and 224 controls. The levels of FCEA across all the studied groups were measured using electronic chemiluminescence immunoassay (ECLIA), and their sensitivity and specificity were used to evaluate their diagnostic potential. The individual diagnostic accuracy of the three indices, as well as their combined diagnostic potential, was compared using the receiver operating characteristic (ROC) curve and chi-square test.

RESULTS

The FCEA had low sensitivity (50%) and high specificity (93.91%) for the diagnosis of IDG, with the area under the curve (AUC) value of 0.781. The AUC of FCEA was higher than that of SCEA for the diagnosis of APC and CRC in the APC, asymptomatic CRC, and APC + CRC-stage I patients. The AUCs of FCEA were 0.708 and 0.691 for the 'double-negative patients' and 'triple-negative patients', respectively. In addition, FCEA could diagnose 45.5% of the 'double-negative' patients, 43.3% of the asymptomatic patients, and 42.9% of the 'triple-negative' patients. The combination of FCEA and FOBT improved the diagnostic value (AUC = 0.916).

CONCLUSION

FCEA has been demonstrated to be a favorable diagnostic marker in intestinal diseases, especially in the APC, asymptomatic CRC, and 'double-negative' or 'triple-negative' CRC patients.

Fecal CEA Has an Advantage in the Diagnosis of Colorectal Cancer at Early Stage

Purpose

Serum carcinoembryonic antigen (SCEA) level is often measured in patients with CRC but suffers from poor sensitivity and specificity as a diagnostic biomarker. CEA is more abundant in stool than in serum, but it has not been widely studied. This study aimed to elucidate the efficacy of fecal CEA (FCEA) as a potential non-invasive biomarker for early diagnosis of CRC.

Materials and Methods

We retrospectively analyzed the determination of FCEA and SCEA levels by electrochemiluminescence. We evaluated the diagnostic accuracy of FCEA and SCEA levels in early-stage CRC patients and healthy controls using ROC curve.

Results

A total of 298 people were included: 115 patients with CRC, 35 patients with adenomatous polyp (APC), 46 patients with non-gastrointestinal cancer (NGC), and 102 healthy controls (HC). The FCEA concentrations in CRC and APC patients were significantly higher than that of NGC and HC, and this is different from SCEA expression in APC and NGC. As a diagnostic biomarker of CRC, FCEA had significantly larger AUC compared with SCEA (.802 vs .735, P  < .001). For identifying early-stage colorectal cancer, FCEA showed better diagnostic efficacy (AUC: .831) than SCEA (AUC: .750), and the combination of the 2 biomarkers was even higher (AUC: .896). The sensitivity of FCEA was higher than that of SCEA (78.7% vs 29.8%). When SCEA was negative, 80.3% of CRC and 54.6% of APC cases could be identified by FCEA.

Conclusion

Compared with SCEA, FCEA has more advantages in the diagnosis of the early stage of colorectal cancer and adenomatous polyps.

Utility of slot-blot-ELISA as a new, fast, and sensitive immunoassay for detection of carcinoembryonic antigen in the urine samples of patients with various gastrointestinal malignancies

Carcinoembryonic antigen (CEA) is the most widely used clinical tumor marker. CEA immunoassay has found acceptance as a diagnostic adjunct in clinical diagnosis of gastrointestinal tumors (GIT). Several immunoassays have been established for detection of CEA in plasma, serum, tissue, feces, and urine of cancer patients using polyclonal or monoclonal antibodies raised against CEA. Some of these assays display both high sensitivity and specificity for the detection of CEA. However, these assays require special and highly expensive equipment and the procedures require long periods for their completion. In the present study, we established a Slot-Blot Enzyme Linked Immunosorbent Assay (SB-ELISA), based on anti-CEA monoclonal antibody (CEA-mAb), as a new, simple, fast, cheap, and non-invasive immunodiagnostic technique for detection of CEA in the urine of GIT patients. Urine and serum samples were collected from 248 GIT patients (58 with pancreatic cancer, 20 with hepatoma, 23 with ampullary carcinoma, 15 with hilar cholangiocarcinoma, 28 with gastric cancer, 14 with esophageal cancer, and 90 with colorectal cancer). Moreover, urine and serum samples were collected from 50 healthy individuals to serve as negative controls. The traditional ELISA technique was used for determination of CEA in the sera of GIT patients using anti-CEA monoclonal antibody. A comparison between the results of both techniques (ELISA and SB-ELISA) was carried out. The traditional ELISA detected CEA in the sera of 154 out of 248 GIT patients with a sensitivity of 59.8%, 51.7% positive predictive value (PPV) and 75.37% negative predictive value (NPV). In addition, it identified 15 false positive cases out of 50 healthy individuals with a specificity of 70%. The urinary CEA was identified by a Western blotting technique and CEA-mAb at a molecular mass of 180 Kda. The developed SB-ELISA showed higher sensitivity, specificity, PPV, and NPV (70.1%, 78%, 62.4%, and 82.13%, respectively) for detection of CEA in the urine of GIT patients. The semi-quantitative SB-ELISA showed a higher overall efficiency of 72.8% versus 63.4% in the case of the quantitative ELISA, for detection of CEA. In conclusion, SB-ELISA is more efficient for detection of CEA in gastrointestinal tumors. It is a simple, rapid, non-invasive, and sensitive assay. Moreover, all steps of the SB-ELISA are performed at room temperature, without the use of expensive equipment; this may enhance the application of this assay in field studies and mass screening programs.

Urinary organ specific neoantigen. A potentially diagnostic test for colorectal cancer

Urinary organ-specific neoantigen from colorectal cancer patients has been used to make a monoclonal antibody, BAC 18.1. In this study we assessed the potential of this antibody for the diagnosis of colorectal cancer. We evaluated binding in both urine and effluent samples and compared it with effluent carcinoembryonic antigen standardized for both volume (nanograms per milliliter) and protein. Urinary organ-specific antigen as detected by BAC 18.1 was significantly greater in 29 cancer patients (A405: 0.717 +/- 0.500) vs 27 controls [0.121 +/- 0.273 (P < 0.05)]. Considerable overlap of binding of BAC 18.1 was observed in the colonic effluent of patients with CRC (N = 13), adenomas (N = 26), inflammatory bowel disease (N = 8), or having a normal colonoscopic examination (N = 24). CEA levels (nanograms per milliliter) were significantly elevated in the effluent samples of patients with a past history of colorectal cancer, as compared to that of normal individuals (P < 0.05). The presence of the M(r) 30,000 organ-specific neoantigen in colonic effluent was also demonstrated by western blot. Organ-specific neoantigen originates in the colon and is excreted into the urine, so the BAC 18.1 binding levels in the urine may be a diagnostic aid for CRC.

Fractionation of carcinoembryonic antigen and related antigens in normal adult feces using a gradient medium Percoll

Fresh normal human feces were fractionated using Percoll gradients and phosphatidylinositol-specific phospholipase C. Studies concerning how cells or cell membrane fragments are fractionated with CEA activity indicate that fecal associated CEA activity is not primarily associated with soluble antigens but with whole cells or fragmented cell membranes.

Mucosal origin and shedding of an early colonic tumor marker defined by Adnab-9 monoclonal antibody

Recent attention has been drawn to the diagnostic potential of tests based on shed colonic tumor markers. Adnab-9 monoclonal antibody raised against neoplastic, potentially premalignant colonic adenomas recognizes a marker in colonic effluent or tissue which correlates with the presence of tumors or risk of colorectal cancer. The origin of this antigen and optimal collection of colonic effluent were investigated by enzyme-linked immunosorbent assay and Western blotting. Mean Adnab-9 binding in effluent samples from colorectal cancer patients even after resection is high as compared with that in normal subjects (P < 0.05). Effluent samples are best collected in the morning hours. Antigen proteolysis may be significant depending on the site and timing of effluent collection, but breakdown products are reactive. Tissue and effluent Adnab-9 binding at any one anatomic site of collection appear to correlate (r = 0.88, P = 0.01). The Adnab-9 antigen is constitutively expressed at low levels throughout the distal bowel and localized to the deepest regions of the mucosal crypts. Other than meconium, no significant levels of binding are found in other body fluids. This antigen is specific for the gastrointestinal tract, its binding in conveniently collected effluent samples correlates with tissue content, and the antigen is constitutively expressed in the crypts of the distal small bowel and colonic mucosa.

Oral colon lavage solutions containing polyethylene glycol may interfere with ELISA detection of tumor-associated antigens in colonic effluent

Immunologic methods for detection of colorectal neoplasia based on examination of stool or colonic effluent are being developed. Most current oral lavage preparations contain polyethylene glycol (PEG), and if PEG adversely interferes with immunologic testing these tests may become less useful. We describe a decrease in sensitivity of ELISA for tumor-associated antigens (TAA) when effluent samples are diluted in PEG-electrolyte lavage solution, equivalent to a commonly used oral lavage solution based on PEG. Radioisotope-labeled antigen binding to plastic plates was decreased by dilution in the PEG lavage solution. Antigen binding, present in colonic effluent collected by the laxative purge method, was absent in effluent collected by PEG oral lavage from the same patient. We conclude that PEG and PEG-containing lavage solutions interfere with ELISA detection of TAA in colonic effluents. We speculate that the in vitro, and possibly the in vivo, effect occurs at the level of antigen binding to the plate either by a steric effect or alteration of charge by the nonpolar properties of PEG.

Increased expression of a putative adenoma-associated antigen in pre-colonoscopic effluent of patients with colorectal cancer

A monoclonal antibody Adnab-9, was raised against antigens derived from benign polyps of the colon. Adnab-9 was tested against pre-colonoscopic effluent material obtained from groups of patients with a macroscopically normal colonscopic examination, histologically confirmed adenomatous polyps and patients with colorectal cancer (CRC). The resultant binding levels displayed little overlap between the CRC group and the normal, and the difference was statistically significant. Since this putative early neoplasia associated antigen is essentially not expressed in CRC extracts, it may originate from a region of the colon predisposed to neoplasia, increasing in expression as the tendency to malignancy progresses, useful in the diagnosis of early stage malignancy.

Faecal carcinoembryonic antigen in colorectal cancer patients

Carcinoembryonic antigen (CEA) has been measured in the faeces of large bowel cancer patients and control subjects to determine whether this measurement might be a useful aid in the diagnosis of large bowel cancer. The mean faecal CEA in 24 cancer patients fell significantly from 10.43 +/- 2.39 micrograms/g pre-operatively to 3.61 +/- 0.72 micrograms/g postoperatively (p less than 0.05). Pre-operative values were not related to either tumour stage or serum CEA. In 20 patients with no known colorectal disease the mean faecal CEA was 5.43 +/- 1.95 micrograms/g which was significantly lower than the mean pre-operative value in the cancer patients (p less than 0.05). In 14 patients with a variety of benign colonic diseases the mean faecal CEA was 7.12 +/- 1.39 micrograms/g which was not significantly different from the mean pre-operative value in the cancer patients. Considerable overlap of values was observed between individual cancer and control patients making the test, as presently carried out, non-discriminatory. If the potential for making the test more cancer specific can be realised, however, faecal CEA determination may permit discrimination between cancer and non-cancer patients at a relatively early stage of disease.

Role of carcinoembryonic antigen assay in the management of cancer

CEA is a molecule produced by a large number of malignant and benign tissues. Measuring levels of CEA circulating in the blood by radioimmunoassay can be used in the management of cancer patients. Because of high false positive and false negative percentages in normal populations, it has not been useful in screening for malignancy. However, in several types of cancer patients the test has been shown to be of considerable clinical value. Elevated CEA levels indicate a poor prognosis in patients with primary colorectal cancer, primary pancreatic cancer, primary breast cancer, and primary lung cancer. Serial CEA titers obtained following cancer treatments can be used to monitor the therapy. CEA can assess the adequacy of surgical removal of a primary colon or rectal cancer, monitor responses to chemotherapy, and assess response to radiation therapy. The greatest clinical impact of CEA has been in the detection of recurrent colon or rectal cancer following surgical resection of the primary malignancy. Early detection of recurrence, when combined with reoperative second-look surgery, may result in 30% long-term survivors.

The relationship of the possible hepatic toxicity of chemotherapeutic drugs and carcinoembryonic antigen elevation

The value of the serum level of carcinoembryonic antigen (CEA) as an indicator of recurrent colorectal carcinoma has been accepted, and the use of serial CEA levels to monitor postoperative chemotherapy has been suggested, However, elevated CEA levels may be associated with nonneoplastic conditions, of which the most difficult to evaluate is hepatic disease. The effect of chemotherapy on hepatic function and therefore on CEA level is not clear. We discuss a patient who, after a potentially curative resection for adenocarcinoma, demonstrated a rise in CEA level in the absence of recurrent carcinoma. This rise correlated with administration of intravenous 5-fluorouracil. Liver biopsy demonstrated severe fatty infiltration with no evidence of cirrhosis. The possible liver toxicity of chemotherapeutic drugs must be considered as a factor responsible for the rise in CEA. Simultaneous assessment of hepatic function is essential to the accurate interpretation of CEA levels, especially in patients receiving chemotherapy.

Carcinoembryonic antigen-like activity in gastric juice and plasma in patients with gastric disorders

Carcinoembryonic antigen (CEA)-like activity in gastric juice and plasma was examined in patients with gastric disease. There was no statistical difference in plasma CEA in normal subjects and in patients with benign gastric cancer. However, four patients with advanced gastric cancer, one with stage III and three with stage IV disease had a very high plasma CEA level. There was significant differences in CEA-like activity in gastric juice in patients with benign gastric disease and early gastric cancer (p less than 0.01) and patients wih benign and advanced gastric cancer (p less than 0.001). These results suggest that measurement of CEA-like activity in gastric juice is a useful adjunct to the diagnosis of early malignant changes in the stomach.

Immunoreactive carcinoembryonic antigen [CEA] levels in feces from colorectal cancer patients

Immunoreactive CEA (IR-CEA) in feces or sera from 20 volunteers and 20 patients with colorectal cancer were measured before and at various intervals after surgery by a radioimmunoassay utilizing a "one step sandwich method." Elevated fecal IR-CEA level was observed in 17 of 20 patients with colorectal cancer; elevated serum CEA levels were observed in only 7 of all patients. There could not be found any correlation between fecal IR-CEA levels and Dukes' classification; there was but a little correlation between serum and fecal IR-CEA levels. In 8 of 14 patients treated by surgery, fecal IR-CEA levels obviously dropped, but in 2 patients with hepatic metastasis they were found rising in spite of colon tumor removal. It was speculated from these data that high values of fecal CEA depend on mass production of CEA by cancer cells. From these observations, it appears that fecal IR-CEA level presents a more ideal diagnostic competency in colorectal cancer than serum CEA level.

Carcinoembryonic antigen (CEA) in gastric juice or feces as an aid in the diagnosis of gastrointestinal cancer

Carcinoembryonic antigen (CEA) levels in the feces and serum were evaluated in 22 colorectal cancer patients and 20 healthy volunteers; in CEA levels gastric juice and serum were also evaluated in 28 gastric cancer patients and 14 peptic ulcer patients. Fecal CEA was found in all of 22 colorectal cancer patients as well as in the 20 healthy volunteers. Elevated fecal CEA levels were observed in the colorectal cancer patients, as compared to the healthy volunteers. The feces of 15 of the 22 colorectal cancer patients contained CEA at concentrations higher than the mean value plus twice the standard deviation of the healthy volunteers. The fecal CEA levels did not correlate directly either with Dukes' stage or serum CEA levels. CEA in gastric juice was elevated significantly in 26 of gastric cancer patients, with the exception of two patients with early gastric cancer. On the other hand, serum CEA was elevated in only nine of the 28 gastric cancer patients. These results point out the distinct value of assaying CEA in the feces or gastric juice as an aid in the diagnosis of colorectal or gastric cancer.

Carcinoembryonic antigen (CEA) levels in benign gastrointestinal disease states

Elevated circulating CEA levels occur in patients with benign gastrointestinal and hepatic disorders. These are usually less than 10 ng/ml. Of clinical importance is the influence of liver disease on the interpretation of CEA. At least 50% of patients with severe benign hepatic disease have elevated CEA levels, most often active alcoholic cirrhosis, and also chronic active and viral hepatitis, and cryptogenic and biliary cirrhosis. Patients with benign extrahepatic biliary obstruction may have increased plasma CEA, the highest in patients with co-existent cholangitis and especially liver abscess. The liver appears to be essential for the metabolism and/or excretion of CEA. Hence, liver work-up is needed to assess any patient with an elevated CEA. A damaged liver may further augment elevated CEA levels due to cancer. The increased circulating CEA observed in some patients with active ulcerative colitis tends to correlate with severity and extent of disease and usually returns to normal with remission. CEA levels also may be mildly elevated in patients with pancreatitis and in adults with colonic polyps. Smoking may contribute to the increased CEA levels seen in patients with alcoholic liver disease and pancreatitis. Therefore, in interpreting mildy elevated circulating CEA levels in patients with GI tract diseases, one must consider benign as well as malignant etiologies.

Immunohistochemistry of carcinoembryonic antigen in the small intestine

Carcinoembryonic antigen (CEA) was demonstrated in formalin-fixed paraffin embedded sections of normal small intestine using an immunoperoxidase method. In all the sections studied the antigen was present over the surface of the villi, within goblet cells and lining the crypt lumens. At the electron microscopic level CEA was identified in mucin granules of goblet cells and in the glycocalyx but not intracytoplasmically. During the study cross-reactivity of antiCEA with Paneth cell granules, red blood cells and endothelium was observed. The shared antigenic determinants responsible for these immunological cross-reactions between CEA and other tissue glycoproteins were found to be carbohydrate in nature. Even when well controlled, misleading immunohistochemical results may be caused by immunological cross-reactions.

Carcinoembryonic antigen (CEA) in the normal human small intestine: a light and electron microscopic study

An immunoperoxidase method for the demonstration of carcinoembryonic antigen (CEA) in tissues was applied to formalin-fixed paraffin embedded and glutaraldehyde-fixed resin sections of normal human small intestine. CEA could easily be demonstrated coating the surface of the small intestine, lining the crypts, and in goblet cells, indicating its presence there in considerable concentration. At the ultrastructural level CEA was localised in the glycocalyx and in mucin granules of goblet cells but not intracytoplasmically.

Carcinoembryonic antigen (CEA) assays in obstructive colorectal cancer

Four of 40 patients with resectable colon or rectal cancer had tumors causing acute large bowel obstruction with colonic dilatation; all 4 patients had preoperative CEA titers above 10 ng/ml with a mean of 28 ng/ml. Thirty-six cancer patients without acute colon obstruction had a mean CEA titer of 4.5 ng/ml; only 6 of 36 patients had circulating CEA titers 10 ng/ml or greater. This suggested that pre-treatment CEA titers in patients with obstructing cancer are unusually high. Multiple CEA assays were performed on two of the 4 patients with colonic obstruction before and after bowel decompressive procedures and prior to their definitive treatment. Relief of obstruction alone produces marked reduction in circulating CEA; this suggested that not only the extent of disease but also the pathophysiological changes associated with obstruction influenced circulating CEA levels.

Carcinoembryonic antigen: clinical application

Carcinoembryionic antigen (CEA) a glycoprotein extracted from colonic cancer tissue (beta-globulin electrophoretic mobility, sedimentation coefficient 7 to 8S, and mol wt approximately 200,000) can be detected and measured by radioimmunoassay. Clinical evaluations of CEA determination have given the following results: In health: (1) Serum CEA level is not influenced by sex, age, blood type, time of blood sampling, or family history of cancer; (2) serum CEA level is influenced by a history of smoking or inflammatory disease of the bowel, lung, pancreas, and other organs (occasionally, a CEA level as high as 10 ng/ml is noted); and (3) currently, CEA positivity is defined as greater than 2.5 ng/ml, however, 5 ng/ml may be more realistic. In cancer: (1) CEA level may be increased in primary cancer of the gastrointestinal (GI) tract as well as in non-GI neoplasia; (2) the CEA test is not recommended for screening to detect early cancer; (3) serum CEA level depends on the stage of the neoplasia and usually is not influenced by the grade of differentiation; and (4) markedly increased (greater than 25 ng/ml serum CEA values are highly suggestive of metastatic cancer, particularly hepatic metastasis. In biological fluid: The CEA or CEA-like activity can be measured in gastrointestinal secretions. Quantitative studies of CEA levels in such fluids may yield more information than is obtainable from studies of serum. However, this possibility needs more study at present. Therefore, the currently available CEA tests cannot replace any of the now standard diagnostic methods for cancer detection. This use for assessment of therapy in selected patients or for following those known to be a high risk for cancer appears promising in preliminary studies, but clinical value, if any, remains to be determined.

Quantification of carcinoembryonic antigen-like activities in normal, human gastrointestinal secretions

The secretion of carcinoembryonic antigen-like (CEA-like) material into the gastrointestinal tract of 28 fasting normal men was quantified by using intestinal perfusion techniques. CEA-like material was recovered from all levels of the gastrointestinal tract. The highest secretory rate was in the colon (mean +/- SE, 2.41 +/- 2.0 mug/minute per colon), followed by pancreatobiliary secretion and pancreatic secretion. The secretory rate from the stomach, duodenum, jejunum, and ileum was less than 20 ng/minute. After perchloric acid extraction, the CEA-like material from the colon had the same chromatographic and radioimmunologic properties as [125I] CEA. These data suggest that the CEA-like material is normally secreted into the gastrointestinal tract and particularly into the colon.

The monolayer and organ culture of human colorectal carcinomata and the associated "normal" colonic mucosa and their production of carcinoembryonic antigens

The carcinoembryonic antigen (CEA) was produced and released by human colorectal carcinomata and also the normal attached mucosa when maintained in both monolayer and organ culture. Immunoperoxidase cytochemical methods were employed for the cellular localization of CEA which was demonstrable only on the neoplastic cells. Gel filtration and immunological methods confirmed that CEA, produced by normal and neoplastic cells, had properties similar to "authentic" CEA derived from metastatic colorectal carcinomata. In addition, two other CEA cross-reacting macromolecules, neither of which was CCEA-2, were produced by these tumours in culture.

Role of serial plasma C.E.A. assays in detection of recurrent and metastatic colorectal carcinomas

Serial estimations of plasma carcinoembryonic antigen (C.E.A.) levels have been carried out in 220 patients with colorectal carcinomas who had potentially and apparently curative surgery. In a two-year follow-up period 53 patients developed recurrences or metastases. In 36 of these patients sustained rises in plasma C.E.A. titres occurred synchronously with or between three and 18 months before the clinical detection of recurrences or metastases. The use of serial plasma C.E.A. assays is therefore recommended as an additional diagnostic aid for the earlier detection of recurrent or metastatic colorectal carcinomas.