Carcinoembryonic antigen in whole serum

A high-affinity antibody-drug conjugates Actuximab-MMAE for potent and selective targeting of CEACAM5-Positive tumors

Antibody-drug conjugates (ADCs) represent a promising class of anti-cancer therapy with an increasingly critical role in treating various tumors. They broaden the range of therapeutic targets, enabling the consideration of tumor-associated proteins that are overexpressed but lack well-defined mechanisms. Carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) is a clinically relevant screening marker due to its tumor-specific overexpression, making it an attractive target for ADC development. However, the therapeutic potential of earlier anti-CEACAM5 ADCs has been limited by side effects and suboptimal drug-to-antibody ratios (DARs), restricting their clinical utility. In this study, we developed a novel anti-CEACAM5 ADC (named Actuximab-MMAE), characterized by high affinity, an optimized DAR, and potent tumor-selective cytotoxicity. Actuximab-MMAE demonstrated rapid and effective elimination of CEACAM5-positive tumors in vivo at low doses, while maintaining a favorable safety profile. These findings highlight Actuximab-MMAE as a promising therapeutic option for CEACAM5-overexpressing tumors, offering a new therapeutic method for targeted cancer therapy.

Unexplained increases in serum carcinoembryonic antigen levels in colorectal cancer patients during the postoperative follow-up period: an analysis of its incidence and longitudinal pattern

BACKGROUND

Carcinoembryonic antigen (CEA) monitoring facilitates the detection of recurrence in patients with colorectal cancer (CRC) after resection. False-positive CEA has been reported in CRC patients with certain comorbidities or smokers. However, limited information is currently available on the frequency of and changes in falsely elevated CEA levels in patients without these conditions.

MATERIALS AND METHODS

We retrospectively examined CRC patients who underwent surgical resection at our hospital between 2001 and 2017, had no recurrence for at least five years, and were free of known factors that may increase CEA. Postoperative CEA levels were retrieved until 2 years before the last contact. For comparison, we similarly selected patients who developed recurrence after resection of CRC during the same period, and CEA levels at initial presentation, at nadir, and at the time of recurrence were reviewed. The patterns of elevated CEA (>5 ng/ml) were classified as transient, repeated, or persistent based on longitudinal changes. The relationships between CEA and carbohydrate antigen 19-9, transaminases, creatinine, and C-reactive protein were examined.

RESULTS

CEA elevation occurred in 90 (20%) out of 446 eligible patients without recurrence at least once during the mean postoperative period of 50.5 months, whereas CEA was >5 ng/ml in 117 (53%) of 221 patients when they developed recurrence. Twenty-seven patients without recurrence showed a transient elevation in CEA, 45 repeated elevations, and 18 a persistent elevation; the frequency of a high preoperative CEA level increased in this order. The majority (98%) of false elevations ranged between 5 and 15 ng/ml. CEA was not associated with other laboratory data.

CONCLUSIONS

Unexplained CEA elevations were observed in 20% of recurrence-free CRC patients after surgery, and were classified into three patterns based on longitudinal changes. A more detailed understanding of patient-specific fluctuations in CEA will prevent unnecessary imaging studies and reduce medical costs.

Detection of carcinoembryonic antigen using a magnetoelastic nano-biosensor amplified with DNA-templated silver nanoclusters

Here we develop a magnetoelastic (ME) nano-biosensor based on the competitive strategy for the detection of a carcinoembryonic antigen (CEA). Specifically, the gold-coated ME material provided a platform and the thiolated single-stranded DNA (HS-DNA) containing a half-complementary sequence towards the CEA aptamer was modified on the surface via Au-S bonding. DNA-templated silver nanoclusters (DNA-AgNCs) containing another half-complementary sequence towards the aptamer were used to amplify the signals by about 2.1 times, compared to those obtained using just the aptamer. CEA aptamers as a bio-recognition element were employed to link HS-DNA and DNA-AgNCs through DNA hybridization. The CEA aptamer preferentially combined with CEA rather than hybridized with DNA. Due to the magnetostrictive nature of the ME materials, the resonant frequency of the nano-biosensor would increase along with the release of DNA-AgNCs and CEA aptamers. The modification process was demonstrated by UV-vis spectra, x-ray photoelectron spectroscopy (XPS), Raman spectroscopy, transmission electron microscope (TEM) and an atomic force microscope (AFM). The nano-biosensor has a linear response to the logarithmic CEA concentrations ranging from 2 pg ml^-1 to 6.25 ng ml^-1, with a limit of detection (LOD) of 1 pg ml^-1 and a sensitivity of 105.05 Hz/ng · ml^-1. This study provides a low-cost, highly sensitive and wireless method for selective detection of CEA.

Clinical Significance of Serum Spermine in Breast Cancer

The diagnostic significance of three polyamines (putrescine, spermidine and spermine), of carcinoembryonic antigen and of phosphoglucose isomerase have been compared in sera of patients with breast cancer or benign breast disease and normal age matched controls. The results of the study indicate that the performance of spermine was more striking than that of any of the other markers. The estimation of spermine may prove to be a valuable parameter not only in detection but also in prediction of recurrence of the disease.

CEA in evaluation of adnexal mass: retrospective cohort analysis and review of the literature

BACKGROUND

The aim of this study was to estimate the diagnostic accuracy of serum carcinoembryonic antigen (CEA) levels in conjunction with Ca125 in the triage of adnexal masses.

METHODS

This retrospective cohort study was carried out in 495 patients referred to the Gynecology Department at Carmel Medical Center due to adnexal mass, between 2005 and 2012. All patients underwent surgery with histopathologically confirmed diagnosis and preoperative measurements of serum Ca125 and CEA. For each marker, sensitivity, specificity, positive predictive value, negative predictive value and risk ratio were calculated.

RESULTS

Combination of CEA with Ca125, compared with Ca125 levels alone, yielded a nonsignificant effect on sensitivity (87.4% vs. 88.9%, respectively, p = 0.64) and specificity (79.3% vs. 74.3%, p = 0.18) in differentiating malignant from benign adnexal masses. CEA levels were higher in mucinous histological types, but were not helpful in detection of borderline tumors. Significantly higher CEA (21.4 ± 53.6 vs. 3.2 ± 11.9 ng/mL, p = 0.0002) and lower Ca125 values (103.9 ± 84.9 vs. 796 ± 1,331.5 U/mL, p = 0.0338) were demonstrated in the 17 metastatic cases compared with 181 primary ovarian malignancies.

CONCLUSIONS

The combination of the tumor markers CEA and Ca125 did not contribute significantly to the detection of malignant adnexal masses compared with Ca125 alone. As our results suggest that higher CEA levels could be useful in differentiating metastatic tumors from primary ovarian malignancy and in diagnosis of mucinous histology, this issue should be investigated in large, well-designed, prospective cohort trials.

Simplified aptamer-based colorimetric method using unmodified gold nanoparticles for the detection of carcinoma embryonic antigen

A new colorimetric aptasensor for the detection of CEA was developed. Aptamer-based colorimetric method with nanoparticles was used for the detection of CEA. The colorimetric aptasensor has potential for the detection of other proteins or nucleotides.

Sensitive detection of carcinoembryonic antigen with magnetic nano-bead and upconversion nanoparticles-based immunoassay

A novel magnetic nanobead-based immunoassay was developed for the quantification of carcinoembryonic antigen (CEA) in human serum in this study. Amine-functionalized Fe(3)O(4) magnetic nanoparticles (MNPs) were conjugated with capture anti-CEA antibodies and amine-functionalized NaY(0.78)F(4):Yb(0.20), Ho(0.02) upconversion nanoparticles (UCNPs) were synthesized and conjugated with detection anti-CEA antibodies, respectively. Based on a sandwich-type immunoassay format, the detection limit for CEA under optimal conditions was as low as 2.5 pg/mL, and the linear range of CEA detection was from 2.5×10(-12) to 1×10(-8) g/mL (I=406.19 logX+428.81) with a correlation coefficient equal to 0.9987. The established method was successfully applied to measure CEA in human serum samples and more sensitive than a commercially available chemiluminescence method. The precision expressed as the relative standard deviation of CEA detection was equal to 5.19% (1 ng/mL) or 4.36% (5 pg/mL), indicating that the developed method exhibited good reproducibility. The results demonstrate that the method offers potential advantages of sensitivity and good reproducibility for the determination of CEA, and is applicable to the determination of CEA in serum samples.

The significance of determining CA 15-3 in the cytosol of breast cancer

The identification of tumor markers in patients who had undergone operation for breast cancer provides important information in the follow-up in addition to evaluation by clinical and visual methods. The aim of our study was to determine the clinical prospective value of CA 15-3, mucin-like carcinoma-associated antigen and carcinoembryonic antigen in preoperative measurement of serum samples in patients with primary breast cancer, and to determine CA 15-3 and steroid receptors in the cytosol of the tumor. The results show that the most exact correlation occurred between serum CA 15-3 and the different stages of the tumor. However, there is no conclusive evidence for the prognosis and the course of the disease from preoperative findings of tumor markers in serum samples or in the cytosol of the tumor in patients with breast cancer.

Tissue binding of lectins in disorders of the breast

Twenty breast lesions including seven scirrhous ductal carcinomas, one infiltrating lobular carcinoma, one colloid carcinoma, four fibroadenomas, and seven cases of fibrocystic disease were analyzed by fluorescence microscopy for the presence and distribution of lectin-binding carbohydrates. Paraffin-embedded tissue sections were tested with wheat germ agglutinin (WGA), Ricin communis agglutinin I (RCA I), peanut agglutinin (PNA), Soybean agglutinin (SBA), Dolichos biflorus agglutinin (DBA), Ulex europaeus agglutinin I (UEA I), and concanavalin A (Con A). Brightest and most consistent staining regardless of the nature of the breast lesion was obtained with WGA followed in approximate order of staining intensity by RCA, PNA, SBA/DBA and Con A. UEA I stained many of the benign breast lesions but no malignant lesions. Lectin binding carbohydrate in benign lesions was localized mainly along the apices of mammary epithelial cells but there was considerable variation in staining patterns among malignant tumors. The fluorescence microscopic arrangement of lectin binding carbohydrate appears distinct for each malignant neoplasm of breast but is more consistent in benign conditions.

Carcinoembryonic antigen levels in cervico-vaginal fluid from patients with intra-epithelial and invasive carcinoma of the cervix

Carcinoembryonic antigen (CEA) levels have been measured in cervico-vaginal washout fluid using the direct CEA Roche radioimmunoassay. Raised CEA levels were found associated with cervical intra-epithelial neoplasia and invasive carcinoma (85% above 300 ng/ml) compared with benign cervical lesions (29% above 300 ng/ml), suggesting that estimation of local CEA levels might be a useful adjunct to cytology and biopsy in the investigation of cervical neoplasia.

Predictive value of serial carcinoembryonic antigen levels in long-term follow-up of ovarian cancer

The predictive value of serial levels of carcinoembryonic antigen (CEA) in tumor monitoring was examined in 213 patients with ovarian cancer; each patient had been followed-up at monthly intervals for at least 12 months. CEA was not detectable throughout the period of observation in 35% of the patients. In general. patterns showing a disappearance of CEA or persistently low levels were associated with a good prognosis, whereas those showing a reappearance or highly elevated and rising levels were associated with a poor prognosis. A transient reappearance of CEA was observed in 10 patients; this did not appear to be associated with tumor recurrence or progression. "False positive" results were obtained in 6 patients in whom no tumor has been clinically detectable to date. "False negative" results were obtained in 4 patients with obvious tumor progression. In terms of a good or poor prognosis, the use of CEA levels was highly accurate in patients with minimal or no residual disease (97% and 89%, respectively); the rate fell to 62% in patients with extensive disease. As the clinical significance and limitations become better known, serial CEA levels should contribute substantially to the monitoring of patients with ovarian cancer.

DNA-binding proteins in the sera of patients with malignant melanoma

Sera of patients with various malignancies are known to contain DNA-binding proteins (DBP) which are not present in sera of normal individuals. In this paper sera of patients with malignant melanoma (MM) were examined as to whether characteristic DBP are present, too. DBP are isolated by DNA-affinity chromatography and represent 0.5-0.9% of all serum proteins. After separation of the DBP by SDS slab gel electrophoresis no typical DBP is detectable in sera of MM-patients. However, quantitative differences are found in sera of patients in the clinical stages I-III and/or tumor level 3-5: 1. All 9 sera of patients who had clinical signs of MM contain more DBP with molecular weight (mw) of 20,000-24,000 dalton than control sera. However, these DBP are only increased in 30% of the 22 sera from MM-patients who had clinical signs for 13-73 months after tumor excision. 2. All sera of the 10 MM-patients of whom sera were drawn twice after tumor excision at an interval of 7-46 months without clinical signs, showed a reduction of DBP with mw 30,000, 68,000, and 165,000.

Carcinoembryonic antigen and beta 2-microglobulin as serum tumor markers in women with genital cancer

A comparative study of carcinoembryonic antigen (CEA) and beta 2-microglobulin (beta 2-MG) in serum was made by radioimmunoassay in 77 women with genital cancer. With a positive level defined as 5 ng of CEA/ml and 3.0 microgram of beta 2-MG/ml, CEA was positive in 31% of the women with cancer of the corpus, 36% of those with cancer of the cervix and 36% of those with cancer of the ovary the corresponding figures for beta 2-MG were 6%, 27% and 56%, respectively. The additional use of beta 2-MG provided an increase in positive results, especially in cases of cancer of the ovary. A direct relationship between the extent of tumor and serum marker level was more evident for beta 2-MG than CEA. There was no correlation between serial levels of CEA and beta 2-MG in most patients. CEA levels appeared to predict subsequent tumor behavior more accurately in patients with good prognoses (ie, complete or partial tumor response), whereas beta 2-MG levels gave the same prediction in those with bad prognoses (ie, nonresponsive or progressive tumor).

Improved performance of a double antibody radioimmunoassay for carcinoembryonic antigen

A new double antibody solid-phase radioimmunoassay (RIA) for carcinoembryonic antigen (CEA) is critically analyzed. The aim of the study was 4-fold: (a) to define the level of sensitivity (a comparison of 3 different assay procedures revealed that our sequential assay was more sensitive than most previously reported RIAs, while competitive and non-equilibrium assay had wider measuring ranges); (b) to analyze recoveries of CEA in either serum, plasma or urine (the recovery, even in urine, was very close to expected values, indicating that no CEA is lost or degraded during brief storage or in the extraction procedure); (c) to evaluate inter- and intra-assay variations, since most clinical management is dependent on serial assays rather than single determinations. The coefficients of variation were low both within and between assays. A change of 3 ng CEA is required for significant change (greater than 2 S.D.) at the normal serum level which is 16 ng CEA/ml in our assay. At levels above normal, a change of 4 ng is required; (d) the assay was also developed for determination of CEA levels in a large series of perchlorid acid treated serum, plasma or urine samples. This forms the basis for an assay suitable for serial assays with high sensitivity and accuracy in various neoplastic diseases.

Clinical correlation between CEA and breast cancer

Elevated plasma CEA levels were observed in 14.2% (2/14) of preoperative patients, 7.9% (3/38) of postoperative patients, and 70.9% (83/117) of patients with metastatic disease. Within these respective groups the simultaneous measurement of hCG, three polyamines and three minor nucleosides further enhanced the detection rates to 69.2%, 54.2%, and 98.6%. It was observed that in patients with at least one elevated CEA, measurement of sequential CEA levels paralleled the clinical course of metastatic disease in 25 patients. Prior to therapy for metastatic disease CEA levels greater than 5 ng/ml were associated with lower response rates and a shorter time to treatment failure than were levels less than or equal to 5 ng/ml. This effect was enhanced in patients also having an elevated hCG level. Hepatic and osseous involvement were associated with a greater incidence of CEA elevations than were pulmonary or soft tissue sites of involvement.

The disparity of indirect and direct zirconyl-gel assays for carcinoembryonic antigen

Experience with the zirconyl phosphate gel (Z-gel) radioimmunoassays for plasma CEA levels below 20 ng/ml (the indirect method) and for levels greater than 20 ng/ml (the direct method) has shown that a disparity of values exists, caused by shifting from one assay to the other. This disparity is at least partially due to PCA-labile proteins reacting in the direct assay. It may be constant for individual patients but varies among patients. The magnitude of this disparity is independent of the CEA level (above 15 ng/ml).

Isolation of tumour-associated immunoglobulins from ascitic fluid

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The quantitative relationship of carcinoembryonic antigen to tumor cells of different organs

Carcinoembryonic antigen (CEA) was measured in extracts of cell suspensions from tumors of the colon, stomach, breast, lung and kidney. Cell suspensions were also obtained from normal tissue surrounding the primary tumors. The number of neoplastic cells in each cell suspension was determined by cytologic criteria. Highest CEA concentrations were found in cells obtained from carcinoma of the bowel. There also appeared to be a greater difference between the concentrations of CEA in colonic tumors and either surrounding normal tissue or serum, than in tumors of other organs. There was no apparent correlation of the concentration of CEA in tumor cells and the presence or absence of metastases. The presence of CEA in normal cells from tissue adjacent to tumors was suggestive of increased synthesis of CEA by these cells in some cases.

Biological markers in breast carcinoma. III. Clinical correlations with carcinoembryonic antigen

Plasma CEA levels were evaluated by radioimmunoassay in patients with breast carcinoma in relation to clinical-pathologic staging, clinical tumor burden, prognosis and organ sites of involvement. Elevated levels were observed in 83/117 (70.9%) patients with metastatic disease, 2/14 preoperative patients and in 3/39 one-six month postoperative patients. Preoperative levels were elevated in two patients; the levels fell to normal after operation. Changes of elevated CEA levels followed the clinical response to therapy in 22/22 metastatic disease patient-trials. The levels decreased with a response in 15 trials and rose with progressive disease or relapse in seven trials. The incidence of CEA elevations and quantitative CEA levels both rose with increasing clinical tumor burden from the postoperative state through the preoperative state to two or more organ sites of metastatic involvement. No relationship was demonstrable among limited samples between preoperative or postoperative CEA levels and prognosis; however, in metastatic disease, pretherapy CEA levels greater than 5 ng/ml were associated with low response rates and early therapeutic failure to chemotherapy. The highest frequency of elevated CEA levels was observed in patients with osseous involvement (79%) and the lowest frequency with skin (52%) and breast (50%) metastases. Liver and osseous disease were also associated with higher mean CEA levels than were other sites of metastatic involvement. CEA levels appear to be elevated in the majority of patients with metastatic disease and be of prognostic importance in metastatic disease. The level in patients with metastatic disease appears to reflect the therapy-associated tumor burden of the host, especially in patients with elevated levels.

Carcinoembryonic antigen in renal allograft recipients and immunosuppressed renal patients

Carcinoembryonic antigen (CEA) was estimated in plasma from 70 patients with a renal transplant, 105 patients with glomerulonephritis who had received immunosuppressive therapy, and 124 healthy controls. There were raised levels in 30% of those with a renal transplant, 10% of those with glomerulonephritis and 2% of controls, and levels were higher in current smokers. CEA levels did not correlate with pre-transplant dialysis time nor with serum creatinine levels, but tended to fall with increasing time after transplantation, especially in non-smokers. CEA levels did not correlate with prednisolone dosage nor with number of rejection episodes, after allowing for time after transplantation and smoking habit. Nine of 70 patients with a renal transplant and three of 105 with glomerulonephritis had cancer, of skin in seven, cervix uteri in four, and colon in one. CEA was raised in all four transplant recipients with a visceral cancer (cervix three and colon one), but in none of the five with cutaneous cancer. Raised CEA levels occurring late after a renal allograft should prompt a careful search for visceral cancer.

Comparison of whole plasma and perchloric acid-extracted plasma assays for carcinoembryonic antigen

A direct, paired, comparison was made of two plasma radioimmunoassays for carcinoembryonic antigen (CEA), between a perchloric acid-extracted, ammonium sulphate precipitation method; and a whole-plasma, double-antibody method. For both assays the same preparations of standard CEA, 125I-labelled CEA, and anti-CEA serum were used. Plasma samples were taken from young healthy subjects (24), cancer-free hospital inpatients (44) and cancer-proven untreated patients (94). Within-batch and between-batch variation were both greater for the extracted-plasma method. Cancer discriminatory ability was assessed by probabilistic means. With cancer-free inpatients as the reference group, no difference between the assay methods was revealed. With young healthy subjects as the reference group the whole-plasma assay was superior.

Carcinoembryonic antigen and cystic fibrosis protein in blood from cystic fibrosis homozygotes and heterozygote carriers

Carcinoembryonic antigen (CEA) activity was measured by radioimmunoassay in blood from cystic fibrosis (CF) homozygotes, heterozygote carriers of CF, normal healthy controls, and other patient controls with carcinomas involving gastrointestinal organs. All samples were also screened by electrofocusing for cystic fibrosis protein (CFP), a metabolic marker previously shown to be associated with the CF gene. Significantly increased levels of CEA activity were found in all CFP-positive groups; however, with one exception all patient controls with marked increases in CEA activity were CFP-negative. Immunodiffusion of perchloric acid extracts of CEA-like material from heterozygote carrier blood indicated that the CEA-like material, which was elevated in homozygotes and heterozygotes for CF, showed only partial identity with two separate CEA preparations obtained from colon carcinomas and was not identical to either A, B, or O(H) blood group substances. This glycoprotein material did, however, react with three different anti-CEA antisera. Our finding of an abnormally increased glycoprotein in cystic fibrosis, taken together with previous reports demonstrating abnormalities in the carbohydrate portion of glycoproteins found in various exocrine secretions in CF, further suggests that the primary defect in this disease is manifested partly as a defect in glycoprotein metabolism. This defect may result from an abnormality in one or more of the glycosyltransferases, possibly caused by a more primary defect in polyamine metabolism.

Detection of circulating carcinoembryonic antigen (CEA) by counter-immunoelectrophoresis

A sensitive method is described for detecting circulating carcinoembryonic antigen (CEA) by combined use of counter-immunoelectrophoresis and intensifiers. Perchloric acid extraction of serum was followed by counter-immunoelectrophoresis against monospecific antiserum to CEA. A precipitin line formed was intensified further by electrophoretic binding of anti-gammaG gamma-globulin and Amido Black staining. Less than 10 ng CEA/ml was detectable. Using this method, a total of 84 sera from patients with or without malignancy was examined. The results obtained were in general agreement with those reported by radioimmunoassay. The method appears to be useful as a diagnostic aid, since it requires neither labeled preparations of purified CEA nor special equipment for assay.

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.

Carcinoembryonic antigen in an unselected elderly population: a four year follow up

Sera obtained in 1969 from 956 unselected elderly persons in Busselton, Western Australia were tested for carcinoembryonic antigen (CEA) by a "double antibody" microradioimmunoassay. Forty-four (4-5%) were positive for CEA (5 ng/ml or greater). Review of health records for the 4-year period subsequent to accession of sera showed that 6 (14%) of the 44 persons positive for CEA died of CEA associated cancers, 15 were heavy smokers, 2 had colonic diverticula and 1 a peptic ulcer. On the other hand, 18 (2%) of the 912 persons negative for CEA developed CEA associated cancers. Thus, a significantly greater proportion of cancers (P = 0-01) was found in the persons positive for CEA. Furthermore, when 21 persons who were positive for CEA in 1969, but clinically well 4 years later, were examined 2 had occult cancer of lung and colon respectively. However, the relatively low yield of diagnosis of cancer from our present population survey led to the conclusion that, if screening for cancer were to be solely dependent on testing for CEA, increased specificity and sensitivity of test systems should be awaited.

Current status of carcinoembryonic antigen assay

The carcinoembryonic antigen (CEA) is a glycoprotein that can be measured by radioimmunoassay and other immunologic techniques. The CEA reagent is currently commercially available in kit form and has been found to be satisfactory for laboratory use. The highest percentage of elevated plasma CEA and the highest CEA titer have been found in patients with entodermally derived tumors. CEA has also been detected in patients with other tumors and in patients with nonneoplastic disease, as well as in heavy cigarette smokers. The present CEA assay cannot be used to screen for cancer in the general population. The greatest clinical usefulness of current CEA assay is in assessing prognosis, in the detection of residual tumors and recurrent disease, and in monitoring chemotherapy and radiotherapy. The use of anti-CEA antiserum as a tumor-localizing agent may be of potential value in the future.

Probabilistic application of plasma carcinoembryonic antigen assay in cancer patients

Plasma carcinoembryonic antigen (C.E.A.) levels in inpatients proved at necropsy to be cancer free were used to assess the ability of the C.E.A. assay to distinguish benign and malignant disease. The patients had a mean C.E.A. level significantly greater than that for young healthy people. In view of the considerable overlap of the ranges of plasma C.E.A. concentration in cancer patients and patients with non-malignant disease a probabilistic interpretation is advocated rather than the use of a simple cut-off between positive and negative. On the basis of the cancer-free control group, 19 out of 64 untreated patients with various solid tumours had plasma C.E.A. levels considered to correspond to a greater than 95% probability of cancer.

Carcinoembryonic antigen and alpha fetoprotein in malignant tumors of the female genital tract

Circulating carcinoembryonic antigen (CEA) and alpha fetoprotein (AFP) levels were measured by radioimmunoassay in 53 patients with carcinoma of the ovary, 16 patients with other malignant genital tumors, and 31 women with nonmalignant diseases of the genital tract. The serum CEA concentration was elevated (greater than 5 ng/ml) in 11 patients with ovarian cancer, 2 patients with endometrial cancer, 1 patient with carcinoma of the cervix, and 1 patient with a benign embryonal cystic teratoma. Elevated CEA levels were found only in patients with advanced malignant disease, while early stages were associated with normal CEA concentrations. AFP levels were normal in all but 1 patient. Both CEA and AFP levels were markedly raised in a case of advanced genital carcinoma arising probably from the ovary. Ascitic fluid of another patient with ovarian cancer contained a high concentration of CEA, giving an identical reaction in immunodiffusion with CEA from colon cancer. The present results indicate that while the increased expression of carcinofetal components takes place in some malignant tumors of the female genital tract, it is usually a late phenomenon.

[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.

Biological markers in breast carcinoma. I. Incidence of abnormalities of CEA, HCG, three polyamines, and three minor nucleosides

Patients with breast carcinoma were screened for abnormal concentrations of CEA, HCG, putrescine, spermidine, spermine, pseudouridine, N2, N2-dimethylguanosine, and 1-methylinosine. Abnormal polyamine levels occurred in less than 15% of the patients. Among the nucleosides, N2, N2-dimethylguanosine was the most frequently abnormal, occurring in 57% of the patients with metastatic disease. CEA levels were abnormal in 30% of postoperative N+ patients and 74% of patients with metastatic disease, while HCG elevations were found in 45% and 50%, respectively. All the patients with one or more marker abnormalities could be detected by measuring only CEA, N2, N2-dimethylguanosine, and HCG. Among these three tests, a singular marker abnormality occurred in 35.8% of the patients, and all three tests were abnormal in 21.8% of the patients. The performance of these three tests in each patient revealed one or more abnormalities 97% of the patients with metastatic disease, and 67% of the postoperative N+ patients.

Rapid radioimmunoassay of carcinoembryonic antigen (CEA) in ultrafiltered perchloric acid extracts: results of a clinical survey

Perchloric acid treatment of the carcinoembryonic antigen (CEA) results in subunits of approximate mol. wt 40 000 to 50 000 with different electrophoretic mobilities and amtogenic deficiences as demonstrated by immunoelectrophoresis. An improved radioimmunoassay is described for the quantitation of CEA using rapid ultrafiltration of serum or plasma extracts. The assay was designed to take into account the changes CEA undergoes during perchloric acid extraction. Absorption of antibodies against a crossreacting non-specific antigen from CEA antiserum did not improve the specificity of the radioimmunoassay as was shown by clinical use of the test in almost 1800 patients.

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.