Monoclonal antibodies against gastrointestinal tumour-associated antigens isolated as monosialogangliosides

Blood group antigen expression in medullary carcinoma of the thyroid. An immunohistochemical study on the occurrence of type 1 chain-derived antigens

Using monoclonal antibodies (MoABs) against blood group determinants and related carbohydrate sequences, it is now possible to clarify their carcinoma-associated modulation at a molecular level. In the present study a panel of MoABs against different type 1 chain derived blood group antigens, comprising A, B, H type 1, Le(a), sialyl-Le(a) (CA 19-9), sialyl type 1 structure (CA 50), and Le(b) was used to investigate their immunoreactivity in 38 medullary carcinomas of the thyroid (MTC) and in normal thyroid tissue. The antigens were not expressed in normal follicular or C-cells but were expressed to a various extent in MTC. The studies revealed some characteristic anomalies in the frequency and patterns of tumor-associated antigen expression. The MoAB C 50 stained 32 of the 38 tumors, H type 1 (Le(d)) was demonstrated in 21 and the Le(b) antigen in 27. The Le(a)- and the A antigen were detected in 10 and 12 tumors and the B antigen in one. From the results some rules about the pathways for tumor-associated re-expression of these antigens can be deduced. Le(a) antigen expression was significantly correlated with the CA 50 and Le(b) antigens. The significant relation observed between A-, H1-, and Le(b) antigen formation in MTC suggests the existence of a carcinoma-associated fucosyltransferase committing the type 1 precursor chain along the H1-antigen pathway, and by further glycosylation to an A-, B-, or a Le(b) antigen. Comparative studies of tumor-associated H type 1 and H type 2 antigen expression revealed that H type 2 antigen synthesis was significantly related to a blood type 0 in the host. On the other hand, H1 antigen reactivity was independent of the AB0 blood type of the hosts and was also detected in H type 2 antigen-negative tumors. These findings support the proposal that even in tumor tissue, H antigen expression is still determined by the interaction of at least two different genes. Despite the occurrence of the precursor substance (CA 50) and the formation of the Le(a)- and Le(b) antigens, indicating the presence of a alpha 1,4-fucosyl-transferase (Lewis-enzyme), only two tumors showed the formation of CA 19-9. In conclusion, the investigations demonstrated the dominant re-expression of three type 1 chain-derived structures in MTC, namely H type 1, Le(b), and CA 50. These findings support the general concept demonstrated in other carcinomas, that fucosyl- and sialyltransferases are preferentially activated in MTC.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison of four serum tumour markers in the diagnosis of colorectal carcinoma

The assessment of the diagnostic power of four serum tumour markers, CEA, CA 19-9, CA 50 and CA 195 for colorectal carcinoma is described, according to recently formulated guidelines. Preoperative serum concentrations of the four markers were determined in 198 colorectal cancer patients and 57 patients with a benign colorectal disorder. The cumulative frequency distributions of the malignant and benign group show strong overlap for all markers, which indicates low diagnostic ability. This is confirmed by the Receiver Operating Characteristic curves, which have areas under the curve of 0.65 (95% confidence interval (CI) 0.58-0.73) for CA 19-9, CA 50 and CA 195 and of 0.70 (95%) CI 0.63-0.77) for CEA. The new tumour markers appear to be of slightly less diagnostic value than CEA for the primary diagnosis of colorectal cancer, although the discrepancy is not statistically significant. The low diagnostic power of CA 19-9, CA 50 and CA 195 may be due to a high proportion of colorectal cancer patients having the Lewis(a-b-) phenotype, who cannot synthesise these markers.

Clinical evaluation of a new serum tumour marker CA 242 in pancreatic carcinoma

The aim of this study was to evaluate the new monoclonal tumour marker CA 242 in the diagnosis of pancreatic carcinoma and to compare it with the established markers CA 50 and CEA. Serum concentrations were determined in 113 patients with jaundice, in 20 patients with laboratory values suggesting cholestasis, and in 60 patients with a suspicion to have chronic pancreatitis. Twenty-four of these 193 patients had pancreatic carcinoma and two patients had carcinoma of papilla of Vater. The sensitivities of CA 242, CA 50 and CEA were 80.7%, 96.1%, and 92.3%, respectively. The specificities were 79.0%, 58.0%, and 59.2%. The sensitivities of combinations of CA 50 and CEA with CA 242 did not exceed the sensitivity of CA 50 alone. The specificity of CA 242 was improved by combining it with CEA (92.2%). The serum marker CA 242 seems to be less sensitive than CEA and CA 50 in the detection of pancreatic carcinoma, but it may prove useful because of its high specificity.

Sensitivity and specificity of CA242 in gastro-intestinal cancer. A comparison with CEA, CA50 and CA 19-9

A serological assay for the quantitative determination of the novel tumour-associated epitope CA242 was developed and used for determination of sensitivity and specificity of CA242 in gastrointestinal cancer. The CA242 assay showed a better tumour specificity than CA50 (and CA 19-9). This was most noticeable in benign hepatobiliary disease. The sensitivity at 90% specificity cut-off level was approximately three times higher for CA242 compared to CA50 in colo-rectal cancer Dukes A, B and C, while in pancreatic cancer the sensitivity of CA242 and CA50 was similar. CA242 was expressed independently of CEA, and the combination of CEA and CA242 gave in colo-rectal cancer considerably higher sensitivity than the use of only one of the markers. This was most pronounced in Dukes A and Dukes B patients. CA242 is a novel tumour marker of potential clinical use, particularly in colo-rectal cancer.

Normal colon of Sprague-Dawley rats. An immunohistochemical study

The patterns of expression of the human-tumor-associated antigens, CO17-1A, GA73-3, BR55-2, GICA19-9, CA50 and carcino-embryonic antigen (CEA) were studied in the normal colonic mucosa (the last three also in the serum) of Sprague-Dawley rats. Four immunohistochemically different segments were identified: caecum, ascending colon, transverse colon and descending colon. The immunohistochemical reactions of the cells at the lower part of the crypt were essential for the distinction of the four segments. In the caecum, the MAbs 17-1A, 73-3 and 19-9 stained the glycocalyx of the cells of the lower part of the crypts and the Golgi apparatus of the intercalated cells (IC). MAb55-2 stained very weakly the goblet-like cells (GLC) of the lower part of the crypt of transverse colon, in addition to a nearly complete lack of reaction in the upper part of the crypts. In the ascending colon, the lower part of the crypts showed a characteristic diffuse staining of the intercalated cells with MAb55-2. The perinuclear and mucosal staining observed in the GLC of the transverse colon with MAbs 17-1A, 73-3 and 19-9 as against the supranuclear and Golgi zone staining observed in the GLC/goblet cells (GC)/columnar cells (CC) of the lower part of crypts of the descending colon with the same MAbs, distinguished the former segment from the latter. The IC demonstrated by immunohistochemistry in the lower parts of the crypts of caecum and ascending colon appear to correspond to the replicating cells of the colonic crypts.

Tumour markers CA 19-9 and CA 50 in digestive tract malignancies

CA 19-9 and CA 50 are tumour marker tests measuring the same carbohydrate structure, sialosyl-fucosyl-lactotetraose--that is, the sialylated Lewis blood group antigen. In addition, the C50 antibody reacts with sialosyl-lactotetraose, which may be expressed in small amounts in some carcinomas. In this study we compared these tests in sera from patients with benign and malignant digestive tract diseases. The sensitivity of the markers for different cancers was also compared at several specificity levels with patients with benign diseases as reference groups. Both markers showed a high sensitivity for pancreatic cancer (77% for CA 19-9; 69% for CA 50) and biliary cancer (88%). The figures in colorectal cancer were almost as high as those reported for CEA; 16-21% elevated values in Dukes A and B tumours and 44-47% in Dukes C and D tumours. The sensitivity for gastric cancer was 48% for both markers. CA 50 had a higher sensitivity for liver cancer (55%) than CA 19-9 (9%), but the proportion of elevated values in benign liver diseases was also higher (33% versus 15%, respectively). Overall, there was good correlation between the CA 19-9 and CA 50 levels, and the difference in sensitivity and specificity was marginal. In clinical practice the greatest value of CA 19-9 and CA 50 is in the diagnosis of pancreatic cancer.

Heterogeneity in antigenic expression and radiosensitivity in human colon carcinoma cell lines

A panel of human colon carcinoma cell lines were characterized regarding both antigenic heterogeneity and variations in radiosensitivity. Monoclonal antibodies were used to study the expression of carcinoembryonic antigen (CEA), gastrointestinal cancer antigen (GICA or CA 19-9) and carcinoma-associated antigen (CA-50). Radiosensitivity was studied with the clonogenic survival technique. Three cell lines, LS 174T, HCTC, and SW 1116 stained positive for all three antigens. HT-29 was positive for CA 19-9 and CA-50 whereas Caco-2 was positive for CEA and CA 19-9. The cell lines SW 620 and LIM 1215 only stained positive for one of the antigens, CA-50 and CEA, respectively. In nearly all positive cases the stainings were very heterogeneous with mixtures of positive and negative cells. One exception was the HCTC cells which stained homogeneously for the CA 19-9 and CA-50 antigens. The neuroendocrinelike COLO 320 cells were negative in all cases. The radiosensitivity varied strongly between the cell lines with Dq-values between 0.8 and 1.9, extrapolation numbers between 2.0 and 4.7, Do-values between 1.1 and 2.8. The surviving fraction at 2 Gy varied between 0.3 and 0.7 with HCTC as the most radiosensitive and HT-29 as the most radioresistant cell line. Thus, there were differences in antigenic expression and intrinsic radiosensitivity between the cell-lines and antigenic heterogeneities within each cell line. The analyzed panel of cell lines will be valuable in studies of dose-effect relations for monoclonal antibodies labeled with toxic radionuclides simulating both antigenic heterogeneity and variations in radiosensitivity.

Preparation and partial characterization of a pancreatic cancer-associated glycoprotein expressing CA50

In our previous study, two antigens associated with pancreatic cancer were prepared from ascites of the patients by using a newly developed affinity chromatography technique; one expressed CA19-9, CA50, Span-1, sialyl SSEA-1, and Dupan-2. This report describes the other part of the antigens, which was scarcely found in normal sera. This antigen was a glycoprotein with a high molecular weight of 1,000,000 in its native state, estimated by size exclusion chromatography on Sephacryl S400. After sodium dodecyl sulfate polyacrylamide gel electrophoresis and blotting analysis, the antigenic activity was observed on the 200-Kd band, and monoclonal antibody of CA50 showed intense reactivity to it. By means of an enzyme immunoassay, CA19-9 determinant was also recognized on it to a lesser extent, although sialyl SSEA-1 and Dupan-2 determinants were scarcely observed. From these observations, the present antigen was considered to be a serum glycoprotein carrying type-1 polylactosamine determinant and differs from previously reported glycoprotein carrying CA19-9 in its insolubility in perchloric acid solution because of its lesser degree of glycosilation. Serum levels of the antigen measured by enzyme-linked immunosorbent assay demonstrated that highly positive rates were observed in 78% of pancreatic cancers, 82% of biliary tract cancers, and 96% of hepatocellular carcinomas.

Elevated serum levels of Dupan-2 in pancreatic cancer patients negative for Lewis blood group phenotype

CA19-9, a serum marker for pancreatic cancer, gives false-negative results in patients who are negative for the Lewis blood group phenotype. To determine whether other markers may compensate for this drawback, serum levels of CA50, Span-1, sialyl SSEA-1 and Dupan-2 were assayed and compared with those of CA19-9 in 207 normal subjects and in 200 patients with pancreatic carcinoma whose Lewis blood group phenotypes were confirmed. In normal subjects with the Lewis negative phenotype, the serum levels of CA50 and Span-1, as well as CA19-9, were significantly low, whereas those of sialyl SSEA-1 were independent of the Lewis blood group phenotype. Serum levels of Dupan-2 were significantly higher in normal subjects with the Le (a-b-) phenotype as compared with those with Le(a-b+). The sensitivity for pancreatic carcinoma was 81% for CA19-9, 84% for CA50, 82% for Span-1, 51% for sialyl SSEA-1 and 63% for Dupan-2. Among the 39 CA19-9 negative patients, 13 were determined as being Lewis negative by the serum dot-ELISA technique. Although the positive rates were essentially comparable when each marker was combined with CA19-9, a highly elevated serum level of Dupan-2, which strongly suggested the presence of malignancy, was most frequently encountered in 39 patients who were not diagnosed by CA19-9 assay, especially those with Lewis negative blood groups. With regard to the three other markers, we found few patients with a highly elevated serum level in either the Lewis-negative or -positive groups. We conclude that Dupan-2 tended to be elevated in patients with pancreatic cancer who were negative for the Lewis blood group phenotype.

Plasma concentrations of CA-50 in relation to tumour burden in exocrine pancreatic cancer

The tumour-associated antigen CA-50 was analysed in plasma from 90 patients with cytologically verified exocrine carcinoma of the pancreas, and related to the size of the primary carcinoma, the largest metastasis of the liver and the degree of tumour-transformed liver parenchyme at 143 examinations. The median concentration of CA-50 in the patients with metastases of the liver was significantly higher than in the group lacking metastases. Spearman rank correlation test at three different levels of CA-50 (all values, exceeding 100 U/ml and exceeding 200 U/ml), showed a correlation between CA-50 and diameter of the primary pancreatic carcinoma in patients with liver metastases, but not in the group lacking liver metastases. No correlations were seen between CA-50 levels and size of liver metastasis or degree of tumour-transformed liver parenchyme. Hence, high plasma concentrations of CA-50 in patients with diagnosed or suspected exocrine pancreatic carcinoma could strongly indicate metastatic processes.

Preparation of pancreatic cancer-associated mucin expressing CA19-9, CA50, Span-1, sialyl SSEA-1, and Dupan-2

A new antigen associated with pancreatic cancer was prepared by immunoaffinity chromatography using Fab'-Sepharose beads. This antigen was a glycoprotein of large molecular weight (Mr greater than 8,000,000) in its native state, estimated by size exclusion chromatography on Sephacryl S400. After sodium dodecyl sulfate-polyacrylamide gel electrophoresis and blotting analysis, several cancer-associated glycoconjugates, including CA19-9, CA50, Span-1, Dupan-2, and sialyl SSEA-1, were detected on the antigenic moiety of Mr 90,000. By an enzyme immunoassay for the antigen, elevated levels were found in pooled sera obtained from patients with various malignant and non-malignant diseases and normal subjects. However, the enhanced expression of CA19-9, Lewisa, or Lewisb epitope on the antigen molecule was restricted to the pooled sera from patients with pancreatic cancer. Furthermore, antigens from pancreatic or gastric cancer expressed ligands with intense and specific reactivity for Bauhinia purpurea (BPA), peanut (PNA), and Vicia villosa (VVA) lectins. The present assay system of the antigen, using both monoclonal antibodies (CA19-9, Lewisa, and Lewisb) and lectins (BPA, VVA and PNA), will provide a useful approach to the diagnosis of pancreatic cancer.

Chemotherapy and immunotherapy of colorectal cancer

More than 50% of the patients with large bowel cancer develop disseminated disease and invariably succumb. Adjuvant chemotherapy with 5-FU and levamisole have been shown to be more efficient than 5-FU alone or in combination with cytostatics. The combination of 5-FU, leukovorin and methotrexate induces prolonged survival with a good quality of life in metastatic colorectal cancer (CRC). During the last decade tumor immunotherapy has been an alternative facilitated by isolation and large scale production of cytokines and monoclonal antibodies. The mouse monoclonal antibody (MAb) 17-1A recognizes a tumor-associated antigen (TAA), present in high concentrations on the surface of gastrointestinal tumor cells. Injections of MAb 17-1A in patients with metastatic CRC induced generation of anti-idiotypic (ab2) in 90% and anti-anti-idiotypic (ab3) antibodies in 47% of the treated patients. The development of ab3 correlated significantly with survival (mean 80 weeks) while ab3- patients survive only 38 weeks. One of 52 patients treated with MAb 17-1A is a complete remission after 66 months, 3 had minor regression and 6 had a stable disease (19% RR). Based on in vitro findings showing increased antibody-dependent cellular cytotoxicity (ADCC) by the combination of granulocyte-macrophage colony stimulating factor (GM-CSF) and MAb 17-1A, 16 CRC patients have been treated with subcutaneously injections of GM-CSF for 10 days and intravenous infusions of MAb 17-1A at day 3. Two of 16 are in CR, 1 in MR and 3 in SD (37.5% RR). Minor side-effects were registered. A further development of immunotherapy of CRC might imply vaccination by injection of specific human anti-idiotypic antibodies (ab2) which mimics the nominal antigen, in order to induce a specific immunity.

Immunohistochemical staining of CA 50 antigen in human bladder cancer. Relation to histologic grade, clinical stage, and prognosis

The immunohistochemical detection of tumor marker CA 50 was studied in bladder cancer of WHO grades I-III. The material consisted of tumors in 83 patients and the mean clinical follow-up time was thirteen years (range 9.6-22 years). The fraction of CA 50-positive cells (FPtot) in microscopic image was scored 0-100 percent. Also the maximally staining region was selected, and the fraction of CA 50-positive cells in this region was scored 0-100 percent (FPmax). The average staining intensity of CA 50-positive cells was scored from 0 to 3 in the whole section (ASItot) and in the maximally staining area (ASImax). The inverse relation between histologic grade, FPtot (p = 0.0001), and ASItot (p = 0.006) was statistically significant. FPtot (p = 0.039) and ASItot (p = 0.018) were also inversely related to clinical stage. Occurrence of metastasis during the follow-up was associated with low CA 50 positivity (FPtot, p = 0.003; ASItot, p = 0.002). The lower the staining intensity or the lower the fraction of CA 50-positive cells, the more aggressive was the tumor. In survival analysis, low FPtot (p = 0.002) and ASItot (p = 0.007) values were related to high risk of bladder cancer death. The results show that immunohistochemical staining of bladder tumor specimens with CA 50 can be used to predict bladder cancer aggressiveness and survival.

Comparison of serological expression of different epitopes on the CA50-carrying antigen CanAg

C203 and C242 are mouse monoclonal antibodies (MAbs) generated using a human colon carcinoma cell line. They recognize novel tumour-associated epitopes present in elevated levels in sera from patients with colon and pancreatic cancer. These epitopes were found to be co-expressed with sialylated Lewisa on the CanAg molecule. To study the association and distribution of the epitopes of CanAg in sera, these new antibodies, together with C50, were used in different combinations in time-resolved fluoroimmunoassays. Relative serum concentrations were examined in patients with various types of carcinoma and in patients with ulcerative colitis and benign pancreatic, and hepatobiliary diseases. A double-determinant assay using C50 and C242 was shown to distinguish carcinoma from benign biliary and hepatocellular diseases better than a single-determinant assay based on C50 as both catching and tracing antibody. The number of sera with elevated CanAg levels from patients with benign obstructive biliary disease was 17 out of 29 using the single-determinant CA50 assay. This was reduced to 4 out of 29 in the double-determinant assay. When sera from patients with liver cirrhosis were analyzed, 16 of 23 patients showed elevated CanAg levels with the C50-C50 combination, but only 4 of 23 patients had elevated antigen values using the C50-C242 assay. The increased specificity was obtained without loss of sensitivity. MAb C203 was evaluated both in a double-determinant combination with C50 and in an homologous assay, but did not contribute either increased sensitivity or specificity as compared with C50-C50.

Comparative study of CA-50 (time-resolved fluoroimmunoassay), Span-1, and CA19-9 in the diagnosis of pancreatic cancer

The clinical diagnostic utility of CA-50 (time-resolved fluoroimmunoassay) and Span-1 was compared with that of CA19-9 by measuring their levels in sera from patients with pancreatic cancer and other diseases. In pancreatic cancer CA-50, Span-1, and CA19-9 showed similar positive rates (84%, 82%, and 81%, respectively). With regard to the ability to distinguish pancreatic cancer from chronic pancreatitis, however, the specificity of CA-50 and Span-1 was higher than that of CA19-9 (85%, 85%, and 79%, respectively). Despite the similar positive rates of CA-50 and Span-1 in pancreatic cancer, the correlation between these two markers was low. Thus, used in combination, they compensated for each other in the diagnosis of pancreatic cancer. In chronic liver diseases, serum levels of both CA-50 and Span-1 were correlated with that of biliary tract enzymes, alkaline phosphatase, and r-glutamyl transpeptidase. And these two markers were more affected by the biliary system than CA19-9, resulting in the significantly higher positive rates. In these diseases immunohistochemical study showed that all three markers were localized in the epithelial cells of the bile duct, with CA-50 and Span-1 showing a similar tissue distribution.

Serological and immunohistochemical studies on sialylated carbohydrate antigens in colorectal carcinoma

Sialylated carbohydrate antigens, such as CA19-9 (sialyl Lea), CA-50 (sialyl Le4), CSLEX1 (sialyl Lex) and SLX (sialyl Lex-i), were assayed in the same preoperative serum samples of 63 patients with colorectal cancer, and compared with CEA. In addition immunohistochemical expressions of sialyl Lea, sialyl lex and sialyl Lex-i antigens were studied in 62 colorectal carcinomas and 42 normal mucosal sites remote from the malignant lesion using monoclonal antibodies CSLEA1, CSLEX1 and FH-6, respectively, in order to elucidate their tumor-specificity and clinical usefulness as a tumor-associated antigen. Serologically, the percent positive rates of CA19-9, CA-50, CSLEX1, SLX and CEA were 30.2%, 17.7%, 23.8%, 16.1% and 44.4%, respectively. In dukes' A and B, these sialylated carbohydrate antigens, especially CSLEX1 and SLX, showed low positive rates, but the percent positive rates of CSLEX1 and SLX correlated with operative radicality. The positive spectrum of CSLEX1 differed from that of CA19-9 in sera, and CEA had no correlation with these two antigens. The immunohistochemical expression rates of sialyl Lea, sialyl Lex and sialyl Lex-i were 88.1%, 17.0% and 9.5% in normal mucosa, but were 77.8%, 90.5% and 71.4% in carcinoma, respectively. These data suggested that the type 2 chain antigens CSLEX1 and SLX, which have high tumor-specificity compared with CA19-9, may be useful in preoperative diagnosis for extension of carcinoma and operative radicality, although early diagnosis using these sialylated carbohydrate antigens may be difficult, while the combined use of CA19-9, CSLEX1 and CEA should make it possible to detect a wide range of colorectal cancer patients.

Evaluation of CEA, CA 19-9, CA-50, CA-195, and TATI with special reference to pancreatic disorders

The tumor markers CEA, CA 19-9, CA-50, CA-195, and TATI were analyzed in patients with pancreatic diseases as well as disorders in the upper quadrant of the abdomen. Two different methods for CA-50, namely CA-50 IRMA and CA-50 DELFIA, which are based on the same monoclonal antibody, were used. The sensitivities, specificities, and predictive values of positive and negative results were calculated at one, three, and ten multiples of the upper reference value ("cutoff") for each method. All the tumor markers except TATI had sensitivities exceeding 90% at one cutoff level, but CEA had low specificity. Poor sensitivities were observed for CEA and TATI at three cutoff levels, whereas CA 19-9, CA-50, and CA-195 had sensitivities and specificities greater than 80%. The sensitivities of these tumor markers decreased at 10 cutoff levels, although the specificities exceeded 95%. The predictive values of positive and negative results were also evaluated at these three cutoff levels. High scores were observed at three cutoff levels. Examined together with the sensitivity and specificity, the evaluation at three cutoff levels indicated that CA 19-9, CA-50, and CA-195 can be used in the diagnostic arsenal for the detection of cancer of the exocrine pancreas in symptomatic patients, and in the differential diagnosis between pancreatic cancer and chronic pancreatitis. Although CA-50 IRMA and CA-50 DELFIA are based on the same monoclonal antibody, there were substantial differences in the levels of CA-50 in a lot of the patients when samples were analyzed by the two methods. These differences were shown to be methodological, and they affected the test evaluations to some extent.

Characterization, isolation and amino terminal sequencing of a rat colon carcinoma-associated antigen

Monoclonal antibodies have been raised against a cell line derived from a dimethylhydrazine-induced rat colon carcinoma. One of these antibodies (MAb E4) has previously been shown to react slightly with normal small intestine and colon, and not with other normal tissues as determined by immunohistochemistry. Using Western immunoblotting we confirmed this tumor specificity. Therefore, the Mr of approx. 66,000 glycosylated antigen (pE4) recognized by MAb E4 appeared to be a potential marker of colon carcinoma. Fifteen human tumor cell lines were tested by flow cytometry for the expression of pE4. This antigen was not detected on these cells. In the rat colon carcinoma cell, pE4 was exclusively found on the cell membrane. pE4 was purified to near homogeneity by immunoaffinity chromatography. The first 20 N-terminal amino acids were identified. Comparison with the NBRF data bank did not reveal a complete homology with known sequenced proteins but similarities were found with the mouse L3T4 precursor, the env polyprotein of human immunodeficiency virus type I, flagellin from Halobacterium halobium and the gp30 from hepatitis B surface antigen. Homology was always found in transmembranous or hydrophobic domains of these proteins. By indirect immunofluorescence analysis of adherent cells and size exclusion chromatography under native conditions, pE4 was found to interact with other molecules and perhaps to be involved in intercellular contact.

Comparison of a new tumour marker CA 242 with CA 19-9, CA 50 and carcinoembryonic antigen (CEA) in digestive tract diseases

The levels of CA 242, a new tumour marker of carbohydrate nature, were measured in sera of 185 patients with malignancies of the digestive tract and of 123 patients with benign digestive tract diseases. High percentages of elevated CA 242 levels (greater than 20 U ml-1) were recorded in patients with pancreatic and biliary cancers (68%). The sensitivity was somewhat lower than that of CA 19-9 (76%) and CA 50 (73%). On the other hand, in benign pancreatic and biliary tract diseases the CA 242 level was less frequently elevated than the CA 19-9 and CA 50 levels. The serum CA 242 concentration was increased in 55% of patients with colorectal cancer. CA 242 detected more Dukes A-B carcinomas (47%) than CEA (32%), whereas CEA was more often elevated (71% vs 59%) in Dukes C-D carcinomas. CA 242 was slightly elevated (ad 41 U ml-1) in 10% of patients with benign colorectal diseases. CA 50 and CA 19-9 had lower sensitivities than CA 242 using the recommended cut-off values. When cut-off levels based on relevant benign colorectal diseases were used, the sensitivities of these markers were similar and somewhat higher than that of CEA. Less than half of patients with gastric cancer (44%) had an elevated CA 242 serum level. CA 242 is a promising new tumour marker, that may be of additional value in the diagnosis of pancreatic and biliary, as well as colorectal cancer, and may be useful in monitoring cancer patients after radical surgery.

Tissue distribution of 2-3 and 2-6 sialyl Lewis A antigens and significance of the ratio of two antigens for the differential diagnosis of malignant and benign disorders of the digestive tract

The authors investigated the tissue distribution of two kinds of sialylated derivatives of Lewis A (Le(a)) antigen in patients with cancers of the digestive system using specific monoclonal antibodies, and evaluated the significance of determining the 2-3 and 2-6 sialylated Le(a) antigen levels for the diagnosis of cancer. In most specimens from patients with cancers of the pancreas, biliary tract, stomach, and colon, the 2-3 sialylated Le(a) antigen was strongly expressed in cancer cells. However, 2-6 sialylated Le(a) antigen was less frequently expressed in cancer cells. The former is therefore more specific to cancer than the latter. Also, the serum level of the 2-3 sialylated Le(a) antigen was significantly higher than that of the 2-6 counterpart in patients with cancers of pancreas, biliary tract, stomach, and colon. The resulting ratio of serum 2-3/2-6 sialylated Le(a) antigens was frequently high in patients with malignancy and was low in patients with benign disorders of these digestive organs. Therefore, the 2-3/2-6 sialylated Le(a) antigen ratio is a useful for the differential diagnosis of malignant disorders in these organs. However, liver disorders were found to be exceptional in that both antigens were mostly absent in hepatocellular carcinoma (HCC) cells in immunohistologic examination, as well as in nonmalignant parenchymal liver cells. Only the epithelial cells of the intrahepatic bile ducts expressed the 2-6 sialylated Le(a) antigen strongly, and expressed the 2-3 sialylated Le(a) antigen moderately. The levels of both antigens were sometimes high in patients with liver disorders, but the ratio always remained low in patients with HCC as well as benign liver disorders such as cirrhosis or chronic hepatitis. The sialylated Le(a) antigens, which sometimes accumulate in the sera of patients with HCC, were concluded to originate from the epithelial cells of the proliferating small bile ducts, and those serum antigens cannot be considered as evidence for the presence of liver cancer cells.

Difference in tissue expression of tumour markers CA 19-9 and CA 50 in hepatocellular carcinoma and cholangiocarcinoma

The expression of tumour markers CA 19-9 and CA 50, defined by the monoclonal antibodies 1116 NS 19-9 (19-9 antibody) and C 50, was studied by the immunoperoxidase technique in formalin-fixed, paraffin-embedded tissue sections from 11 hepatocellular carcinomas and 10 cholangiocarcinomas of the liver, and from specimens of normal liver and liver cirrhosis. The 19-9 and C 50 antibodies react with sialosylfucosyllactotetraose, corresponding to sialylated blood group antigen Lewis, and the C 50 antibody also with another sugar moiety, sialosyllactotetraose. Neither marker was cancer specific. The CA 19-9 and CA 50 antigens are normal constituents of bile ducts. Nine out of 10 cholangiocarcinomas stained for CA 50, and eight out of 10 for CA 19-9. There was no apparent difference between the staining pattern of CA 19-9 and CA 50. Hepatocellular carcinomas were consistently negative for both markers. Thus, hepatocellular carcinomas and cholangiocarcinomas showed a clear difference in the reactivity for tumour marker antigens CA 19-9 and CA 50. This difference might be of clinical importance in the differential diagnosis between hepatocellular carcinoma and cholangiocarcinoma.

CA 50 determination in body fluids: can we screen patients at risk for gastric cancer?

CA 50 (a tumor-associated gangliosidic antigen) levels have been determined by an RIA test in serum, gastric juice and urine of patients undergoing upper gastrointestinal tract endoscopy: 22 control subjects (no macroscopic or microscopic lesions), 29 patients with chronic atrophic gastritis, 20 with epithelial dysplasia and 16 with gastric cancer entered the study. Gastric juices were also tested for pH, protein concentration and specific gravity, urines for protein concentration and osmolarity. Serum and gastric juices were also tested for CEA levels and the results obtained with the two markers compared. In patients with gastric cancer, CA 50 gastric juice levels were statistically higher than in controls; a wide overlap was however present among groups, and sensitivity and specificity were respectively 38% and 85% for serum and 69% and 82% for gastric juice. Sensitivity and specificity were respectively 23% and 89% for CA 50 determination in urines. In this case, no statistically significant difference was observed between gastric cancer and control patients. A trend toward higher median values was observed in advanced with respect to early gastric cancer. A correlation was found between gastric juice and serum CA 50 levels, as well as between serum and urine levels of the marker. A correlation was also observed between CA 50 values and protein concentration in gastric juice and with osmolarity in urines. Overall, CA 50 levels were statistically higher in patients with intestinal metaplasia than in those who did not present the lesion. Increased CA 50 gastric juice levels are also observed in patients with chronic atrophic gastritis and epithelial dysplasia. CA 50 gastric juice and urine levels appear to be dependent, at least in part, on the concentration of the fluid.

Therapy of colorectal carcinoma with monoclonal antibodies (MAb17-1A) alone and in combination with granulocyte monocyte-colony stimulating factor (GM-CSF)

A mouse monoclonal antibody (MAb17-1A) (IgG2A) against colorectal carcinoma cells was used to treat patients with metastatic disease. Major direct effector functions of MAb seem to be ADCC (antibody dependent cellular cytotoxicity), CDC (complement dependent cytolysis) and apoptosis ('programmed cell death'). Thus, a high tumor cell saturation of the MAb should be achieved. Increasing doses of MAb to the patients increased the total area under the concentration curve and thus the exposure of tumor cells to MAb. However, the response rate (with complete + partial + minor response + stable disease defined as response) was not augmented. In total, 10/52 (19%) patients responded and in fact lower doses (less than 2 g) might induce a higher response frequency (9/52) than higher doses (greater than 2 g) (1/52). During treatment, the numbers of cytotoxic cells (lymphocytes and monocytes) increases in the tumor lesion and complement components were deposited. As ADCC may be important, effector mechanism attempts were made to augment the cytolytic capability of the effector cells by simultaneously giving the patients GM-CSF. The combination of MAb17-1A + GM-CSF augmented the ADCC activity of blood mononuclear cells and a heavy infiltration of monocytes could be noted in the tumor. Out of 15 available patients 6 (40%) showed a response.

Comparison of seven iodine-labelled monoclonal antibodies in nude mice with human colon carcinoma xenografts

The biokinetics of seven 131I-labelled monoclonal antibodies (MAbs), directed against human colon carcinoma and one 125I-labelled unspecific MAb have been examined. The study in nude mice, carrying human colon carcinoma, was intended to be a step in the selection of the most suitable antibody for clinical scintigraphy. The biological half-life in blood was found to be between 1.3 and 7.4 days for the different MAbs. Chromatography of plasma samples showed that the radioiodine was mainly bound to IgG-sized molecules. The (normal tissue)/blood ratios were similar for all the MAbs. The tumour/blood ratio was 0.41 for the unspecific MAb and 0.49-1.1 for the specific MAbs, and the tumour/muscle ratio was between 3.2 and 6.8 for the specific MAbs 6 days after injection. For one MAb tumour/blood and tumour/muscle ratios were 3.9 and 9.8 respectively 9 days after injection. Localization indices were at their highest 2.6 6 days after injection. For at least two of the monoclonal antibodies the tumour/blood and tumour/muscle ratios found are high enough to justify clinical trials regarding their usefulness for scintigraphy of colon cancer in man.

Serum diagnostic tests for pancreatic cancer

Serological tests for pancreatic cancer have been criticized too harshly as a result of being tested in inappropriate roles. They are never likely to become sufficiently specific for screening an asymptomatic population unless some way can be found of defining a population with a particularly high risk for the disease. Nor are they appropriate in the investigation of the jaundiced patient. The markers that are carried by secreted mucins seem the most promising and in view of the marked heterogeneity of carbohydrate expression on mucins a combination of tests for two or three carefully selected markers is likely to be better than one. The high cost per test that results from using commercially available radioimmunoassay kits with a short shelf-life can be reduced by using enzyme-linked assays which have a much longer shelf-life. These tests are likely to be of most help in the investigation of non-jaundiced patients with unexplained abdominal pain or weight loss. In this group of patients it seems probable that serological tests will compliment scanning techniques but further studies are needed to assess this.

Recognition of the polypeptide core of mucin by monoclonal antibody MUSE11 against an adenocarcinoma-associated antigen

Monoclonal antibody (MAb) MUSE11 detects an adenocarcinoma-associated antigen and is useful for the serodiagnosis of pancreas cancer. We established a sandwich enzyme immunoassay using MAb MUSE11 and MAb DF3 against a breast cancer-associated mucin core protein as a catcher and a tracer, respectively. With this assay system, the binding of the tracer MAb DF3 to an antigen in the human kidney tissue lysate was clearly inhibited by MAb MUSE11. In addition, MAb MUSE11 showed a significant binding activity to the synthetic peptide corresponding to the tandem repeat of a human epithelial mucin core protein. These data suggest that MAb MUSE11 could detect the polypeptide core of a mucin, and may be of use for studying mucin as a gene product.

Radioimmunolocalization of tumours of the pancreas and biliary tree

Although localization of tumours by radiolabelled antibodies is in principle a specific method, in practice the technique is dependent upon qualitative and quantitative differences in antigen expression between malignant and benign tissue. Pancreatic disease is similar to other gastrointestinal malignancies in which RIL has been evaluated. The expression of a small number of antigens has been demonstrated to enable some differentiation between pancreatic cancer and principally chronic pancreatitis. To date the cross-reactivity of antibodies has resulted in limited specificity but it does appear that CEA, CA19-9, TAG-72 and BW494 are appropriate target antigens. Studies in RIL have indicated that BW494 has the optimal characteristics, although studies with chronic pancreatitis are limited. Further information on the fate of the administered antibody and the interactions with tumour-associated antigen is required before clinical application can be considered. At present this technique does not have a role in primary diagnosis. In the near future, however, RIL may prove useful as a complementary investigation to conventional methods particularly in the assessment of recurrent malignancy.

The effect of non-insulin-dependent diabetes on serum concentrations of tumor-associated carbohydrate antigens of CA19-9, CA-50, and sialyl SSEA-1 in association with the Lewis blood phenotype

Serum concentrations of the tumor-associated carbohydrate antigens CA19-9, CA-50, and sialyl SSEA-1 were measured in non-insulin-dependent diabetic patients without diseases causing the elevation of those antigens, and the relationship to diabetic conditions was studied. The patients of the Lewis blood group phenotype of Lea (23%) had higher serum CA19-9, CA-50, and sialyl SSEA-1 than those of Leb (67%) and Le(-) (10%). Lea patients with high HbA1c (greater than 10%) had significantly higher serum CA19-9 and CA-50 than those with low HbA1c (less than or equal to 7%). Leb patients with high HbA1c also had elevated CA19-9 and sialyl SSEA-1. In Leb patients, diabetic nephropathy was associated with increased CA19-9 levels. Diabetic retinopathy was also accompanied by high carbohydrate antigens in Leb patients, but the difference was not significant. Leb patients treated with sulfonylurea or insulin had increased CA19-9 and CA-50. The changes in serum concentrations of these carbohydrate antigens might have some relationship not only to the Lewis blood phenotype, but also to diabetes.

Composition and production of pancreatic tumor related antigens

Large numbers of specific and highly purified antibodies that react with tumor-associated antigens (TAAs) have been produced over the last decade as a result of the hybridoma technology that was developed during the previous decade. The availability of monoclonal antibodies (MAbs) rapidly led to studies of their clinical applicability. It has recently become apparent that further characterization of TAAs at the molecular level is needed before the MAbs, which react with TAAs, can have extensive use in the diagnosis and treatment of pancreatic cancer. The information that is currently available concerning the molecular composition and production of pancreatic TAAs is summarized in this presentation.

A clinical evaluation of various tumor markers for the diagnosis of pancreatic cancer

Many substances that are widely used as tumor markers for detecting pancreatic cancer are discussed. Some are good indicators, but some are not. Among them, CA 19-9 and SPan-1 have higher sensitivity and specificity for diagnosis of pancreatic cancer. However, these markers are neither tumor-specific nor pancreatic-cancer-specific. Accurate understanding of the measurement of serum tumor markers makes it possible for them to be useful adjunctive tools for detecting pancreatic cancer, even in small cancers, and for monitoring patients after treatment.

Cancer-associated tumour markers CA 19-9 and CA-50 in patients with pancreatic cancer with special reference to the Lewis blood cell status

Monoclonal antibodies 19-9 and C-50 were used to assay the cancer associated tumour antigens CA 19-9 and CA-50 in plasma from patients with confirmed pancreatic cancer, and related to the blood group and Lewis blood cell status. The plasma expressions of CA 19-9 or CA-50 were similar, including cases where the patients had Lewis phenotype Le (a-b-). However, analyses of both the tumour antigens could be used to differentiate the presence of cancer from its absence in Le (a-b-) individuals. The findings indicate that the targets for the monoclonal antibodies 19-9 and C-50 are similar. The practical implications of these findings are discussed.

Changes in glycolipid expression in human testicular tumor

Glycolipids were extracted from testicular tumor tissues of 13 patients, and their pattern of expression compared with that of normal testicular tissue. The most conspicuous and consistent change in the tumor extracts was marked accumulation of CTH (ceramide trihexoside). Structural analysis by enzyme cleavage showed that CTH which accumulated in the tumor tissue was Gb3 (Gal alpha 1-4Gal beta 1-4Glc beta 1-Cer). Immunohistochemistry using anti-Gb3 monoclonal antibody (MAb) (1A4) also indicated massive accumulation of Gb3 in the tumor tissue. Gb3 may be a new marker of testicular tumors, especially seminomas, for which useful markers are so far lacking.

CA-50 serum level in patients with prostate cancer

CA-50 antigen is considered to be a generalized carcinoma-associated antigen. CA-50 serum levels were measured by solid phase radioimmunoassay using a specific monoclonal antibody. Sera of 49 patients with prostatic cancer of different clinical stages, 43 patients suffering from BPH, and 28 healthy males were tested. Positive test results were observed in 57.1% of patients with prostate cancer values ranging from 42.9% in stage A to 66.7% in stage D. Increased CA-50 levels were found in 11.6% of patients with BPH.

Sialyllacto-N-fucopentaose II (sialylated Le(a)) coupled to humanserum albumin used as standard in immunoassays of tumour associated antigens CA 19-9 and CA-50 in serum

Penta and hexasaccharides from human milk, containing sialic acid and/or fucose residues were conjugated to human serum albumin and used as antigens in three different methods for CA 19-9, two methods for CA-50 and one method for CA-195. In accordance with reported results, the 19-9, CC 3C 195 and C-50 monoclonal antibodies were found to react with the sialyllacto-N-fucopentaose II conjugate, although to a different extent. A negligible reaction was observed with the isomeric conjugate, sialyllacto-N-fucopentaose III, and no reaction was seen with the sialyllacto-N-tetraose conjugate. The use of defined oligosaccharide conjugates for the standardization of assays of tumour markers in serum is discussed.

Production of monoclonal antibody to human esophageal cancer cell line

The immunization of Balb/C mice with esophageal cell line KYSE-50 established from poorly-differentiated esophageal squamous cell carcinoma, resulted in obtaining the monoclonal antibody KYMN-28-5. This monoclonal antibody is of the IgM class and recognizes a carbohydrate antigen contained in glycoproteins with molecular weights of 53 and 56K, and in neutral glycolipids extracted from teratomas. Tissue staining revealed that this monoclonal antibody reacts strongly with malignant tumors but only weakly, or not at all, with normal tissues, apart from squamous epithelial tissue. KYMN-28-5 is thus a useful tumor marker which will improved the accuracy of serological diagnosing squamous cell carcinoma when combined with the measurement of SCC antigen.

Tissue expression of the tumour associated antigen CA242 in benign and malignant pancreatic lesions. A comparison with CA 50 and CA 19-9

The expression of a novel tumour associated antigen CA 242, defined by the monoclonal antibody C 242, was studied by immunoperoxidase staining in formalin-fixed, paraffin-embedded tissue sections from normal pancreata, pancreata with pancreatitis and benign and malignant pancreatic neoplasms. The antigenic determinant of the C 242 antibody is a sialylated carbohydrate structure, related but chemically different from tumour marker antigens CA 19-9 and CA 50. Thirty-eight of 41 (93%) well to moderately differentiated ductal adenocarcinomas of the pancreas and all cystadenocarcinomas were positive for CA 242. The staining was most intense in the apical border of the cells, and in the intraluminal mucus. Only two out of seven poorly differentiated adenocarcinomas stained, and the number of positive cells was smaller than in well differentiated carcinomas. Only occasional cells were stained in one out of five anaplastic carcinomas. Part of large ducts were positive in 91% (21/23) specimens of chronic pancreatitis. In acute pancreatitis small terminal ducts, centro-acinar cells and some large ducts stained for CA 242. In normal pancreas only a few small terminal ducts were CA 242 positive. Carcinomas always stained more strongly for CA 242 than normal pancreatic tissue adjacent to the carcinoma. The results of CA 242 are compared with those of tumour marker antigens CA 50 and CA 19-9. Serum CA 242 levels were determined in 23 of the patients with pancreatic cancer using a fluoroimmunoassay. Fifteen (65%) patients had an elevated value. There was no clear-cut correlation between the serum levels and the immunohistochemical expression of the CA 242 antigen. The expression of CA 242 in pancreatic tissue resembles that of CA 50 and is similar to CA 19-9. The antigen is expressed in serum of many patients with pancreatic cancer and, therefore, is a potential candidate for a serum tumour marker.

Enhanced recognition of human colorectal tumour cells using combinations of monoclonal antibodies

Murine monoclonal antibodies directed against tumour associated antigens are potentially useful in tumour diagnosis and therapy. However, all the antigens they recognise may be heterogeneously expressed on tumours and this may allow escape of cells from therapy if a single monoclonal antibody is used. One approach is to use combinations of monoclonal antibodies recognising complementary cell surface antigens. A flow cytometric method which allows accurate quantitation of the intensity of staining and the percentage of fresh primary tumour cells binding a series of monoclonal antibodies has therefore been developed. This allows calculations as the number of drug molecules which could be potentially delivered by each monoclonal antibody and the optimal combination of antibodies which should be used. Monoclonal antibodies recognising Y hapten (C14), CEA (228, 161) and 791T-p72 antigen (791T/36) have been screened as a possible combination for colorectal cancer. There was inter-tumour variation in the binding of all the monoclonal antibodies although combinations could reduce or abrogate this problem. A combination of the monoclonal antibodies C14, 228, 791T/36 and 161 would recognise 100% of tumours. Sixty per cent of tumours bound all four antibodies, 78% any three, 90% any two and 100% any one antibody. There was also intra-tumour variation in the number of tumour cells per lesion that were recognised, the best monoclonal antibody, 161, stained a mean of 59% of cells per tumour whereas the anti-cytokeratin monoclonal antibody stained a mean of 74% of cells per tumour. An increased intensity of staining of tumour membranes was observed when a combination of C14 and 228 was used compared to binding of individual antibodies. Furthermore there was still no significant binding to normal colon membranes. Combinations of monoclonal antibodies which recognise a high percentage of tumours are likely to be necessary for monoclonal antibody drug targeting to prevent tumour recurrence and/or metastases.

Improvement of the rapid immunoperoxidase staining method for intraoperative pathological diagnosis of pancreatic cancer using microwave irradiation

The rapid immunostaining of gastrointestinal cancer-associated antigens, CA19-9, CEA, DUPAN2, and CA50, for intraoperative pathological diagnosis of pancreatic cancer can be completed in only 13 min by applying microwave irradiation, which was used to accelerate the incubation of the primary antibody. Only 3 s irradiation at 500 W for fresh-frozen sections produced specific antigen staining of greater intensity than that obtained with longer incubation, and tissue preservation was satisfactory with minimal non-specific background staining. This rapid immunoperoxidase staining method on the cryostat section of pancreatic biopsy specimens can provide important information for determining an appropriate operative method for pancreatic cancer patients.

Preoperative prediction of late cancer-specific deaths in patients with rectal and rectosigmoid carcinoma

The possibility of predicting late cancer-specific deaths from (a) the preoperative serum levels of three tumour markers, carcinoembryonic antigen (CEA), tissue polypeptide antigen (TPA) and an antigen defined by the C-50 antibody (CA-50), from (b) one clinical factor of independent prognostic relevance, polypoid tumour growth, and from (c) Dukes' stage was evaluated in 276 patients with rectal carcinoma operated upon with curative intent ("potentially curable"), and in the 251 of those patients who were considered to be "potentially cured" after surgery. Using the Cox regression model, the preoperative serum levels of the tumour markers strongly predicted the cancer-specific mortality within the first year after surgery. This ability of S-CEA and S-CA-50 diminished for the mortality during the second year after surgery, and virtually disappeared thereafter. The ability of S-TPA to predict cancer-specific deaths did not change as dramatically with time as that of the other two markers, particularly in the group of "potentially cured" patients. Patients with polypoid tumour growth had a good prognosis which did not appear to change with time. Similarly, the prognostic information provided by Dukes' staging system was valid at all studied time intervals after surgery, although it declined after the second year. The importance of these results in relation to the selection of patients for adjuvant treatment is discussed.

Tissue expression of the cancer-associated antigens CA 19-9 and CA-50 in chronic pancreatitis and pancreatic carcinoma

The expression of the gastrointestinal cancer-associated antigens CA 19-9 and CA-50 was studied in 43 ductal pancreatic carcinomas, 1 mucinous cystadenoma, 1 signet-ring-cell carcinoma, 42 pancreata with chronic pancreatitis, and 10 normal fetal and adult pancreata. The anti-CA-50 antibody gave a more intense and more uniformly distributed staining of the ductal epithelial cells than the anti-CA 19-9 antibody. Both antigens, however, exhibited the same staining pattern of ductal epithelial cells in normal pancreas and chronic pancreatitis. Well differentiated carcinomas showed a predominantly membrane-bound antigen expression, whereas moderately and poorly differentiated carcinomas gave a more diffuse cytoplasmic staining. Epithelial dysplasia could not be differentiated by the staining pattern from normal, hyperplastic, metaplastic, or neoplastic cells. The immunohistochemical reaction with these anticarbohydrate antibodies, therefore, does not allow a qualitative discrimination between chronic pancreatitis and pancreatic carcinoma. CA 19-9, which expression depends on the Lewis gene, was negative in two patients with Le(a-b-) phenotype. Although anti-CA-50 antibody was reactive with the cancer cells of these 2 patients, the staining was weak and heterogenous.

Enzyme-linked PNA lectin binding assay compared with CA19-9 and CEA radioimmunoassay as a diagnostic blood test for pancreatic cancer

Previous studies have shown that sera from patients with pancreatic cancer often contain a mucus glycoprotein that expresses the oncofetal antigen galactose 1-3, N-acetyl galactosamine, which is the T blood group antigen and the binding site for the lectin peanut agglutinin (PNA). An enzyme-linked lectin assay has been developed to quantify PNA-binding glycoproteins in serum and has been evaluated as a serological test for pancreatic cancer. Sera were studied from 53 patients with pancreatic cancer and 154 controls, including benign obstructive jaundice, acute and chronic pancreatitis, chronic liver disease and inflammatory bowel disease. The enzyme-linked peanut lectin assay proved highly reproducible and has 77% sensitivity and 83% specificity for pancreatic cancer, results that are very similar to those achieved in the same sera by CA19-9 radioimmunoassay (75% sensitivity, 82% specificity with the upper limit of normal set at 37 u ml-1). CEA assay proved less useful (60% sensitivity, 47% specificity). In this study better results were obtained if an upper limit of normal of 50 u ml-1 was used for CA19-9 (75% sensitivity, 92% specificity). Combination of CA19-9 assay with the upper limit set at 50 u ml-1 and the peanut lectin assay improved the sensitivity to 85% with only a slight fall in specificity (85%). These results compare well with published results for ultrasound and CT scanning.

Preoperative prediction of outcome in patients with rectal and rectosigmoid cancer

This study evaluated the possibility of dividing patients with primary rectal carcinoma into prognostic groups before surgery based on preoperative serum levels of carcinoembryonic antigen (CEA), tissue polypeptide antigen (TPA), and an antigen defined by the monoclonal antibody C-50 (CA-50), as well as on some easily available clinical characteristics providing prognostic information. The evaluation was made both for patients who were "potentially curable" by surgery and, among those, for patients who were "potentially cured." Using the Cox regression model, the serum levels of the three tumor markers, together with the knowledge of whether or not the tumor was polypoid were combined to make up the set of variables that best predicted patient outcome. These variables and their associated regression coefficients were used to classify the patients according to prognosis. The cancer-specific mortality rate for the 24% of potentially curable patients with the best prognosis was 15%; for the 26% of potentially curable patients with the worst prognosis, the cancer-specific mortality rate was 57%. For potentially cured patients among those who were potentially curable, the cancer-specific mortality rates for patients with the best and worst prognoses were 14% and 47%, respectively. The information provided by these preoperatively available variables together was comparable with that given by Dukes' staging system, but the latter system was more informative. On the other hand, some of the preoperative variables provided information not provided by Dukes' staging system.

Clinical significance of mucin-like high molecular weight glycoprotein originated from lung cancer as tumor marker

A high molecular weight, mucous glycoprotein (MG) from the pleural fluid of lung adenocarcinoma was purified by the DEAE-cellulose, gel-filtration and wheat germ agglutinin affinity chromatography. Protein portion of the molecule was composed of amino acids rich in serine, threonine and proline, but methionine and tyrosine concentrations were relatively low. About 65% of the weight, was composed of galactose, galactosamine, glucosamine, fucose and sialic acid. The gel-filtration pattern on Sepharose 4B revealed Mr greater than 10(6) Da. The SDS-PAGE pattern revealed a main band at the position of the Mr about 350 kDa under the reducing condition. Rabbit antibody against this molecule recognized mainly the peptide portion, and the radioimmunoassay (RIA) using the double antibody method was developed by this antibody. Serum MG level was low in healthy subjects and in benign diseases (0.8 +/- 0.7 U/ml; mean +/- SD and 1.1 +/- 2.3 U/ml, respectively). Thus, 3 U/ml was used as the cut-off value. The mean of serum MG levels and positive rates in malignant diseases were significantly high; 4.4 U/ml and 32.3% in lung cancer, 20.1 U/ml and 77.5% in pancreas cancer 11.6 U/ml and 64.3% in gastric cancer, 12.9 U/ml and 57.1% in hepatoma, 12.3 U/ml and 77.8 in colon cancer. Other malignancies such as ovarial and uterus cancer showed also high levels. Elevated values in these malignancies were observed frequently in patients with metastasis. On the other hand, the false positive cases were found in 10% of benign diseases. Determination of MG seems to be useful for the detection of several kinds of malignancies, but it is not adequately sensitive as a screening method for early cancer detection.

Mouse monoclonal antibodies for experimental immunotherapy promotes killing of tumor cells

Monoclonal antibodies (MAbs) produced against a human colon adenocarcinoma cell line, Colo-205, were tested in antibody-dependent macrophage-mediated cytotoxicity (ADMMC) assays. The antibodies C163, C215, C245 (IgG2a isotype); C151, C239, C241, C242 (IgG1); C152 (IgG2b); and C50 (IgM) were evaluated for their ability to promote killing of Colo-205 cells by thioglycollate-elicited peritoneal mouse macrophages. The concentrations of antibodies tested in ADMMC assays ranged from 1.0 ng/ml to 100 micrograms/ml, and the concentration at which 50% of tumor cells were lysed was used to characterize each antibody. Antibodies of the IgG2a isotype promoted the strongest macrophage-mediated tumor cell lysis effects in vitro. MAbs C215, C163, and C245 were also tested in nude mice which had been inoculated with Colo-205 cells. Tumor suppression was observed in mice injected with MAbs, supporting our ADMMC findings in vitro. Animals treated with MAbs had fewer and smaller tumors, and longer periods of latency between the inoculation of tumor cells and development of tumors, compared to mice sham-treated with PBS. However, in a study of established tumors, C215 antibody did not suppress tumor growth. Serum collected from MAb-treated mice promoted lysis of Colo-205 cells in ADMMC assays while serum from sham-treated mice did not.

Tumor markers carcinoembryonic antigen, CA 50, and CA 19-9 and squamous cell carcinoma of the esophagus. Pretreatment screening

Pretreatment serum levels of the tumor markers carcinoembryonic antigen (CEA), CA 50, and CA 19-9 in 95 patients with squamous cell carcinoma of the esophagus and 32 age-matched controls were compared. Thirty-nine percent of the cancer patients showed elevated (greater than or equal to 5 micrograms/l) serum CEA levels, 41% had elevated (greater than or equal to 17 U/ml) CA 50 levels, and 13% showed elevated (greater than or equal to 37 U/ml) CA 19-9 levels. The tumor markers showed a considerable degree of complementarity, and combined tumor marker analysis increased the sensitivity to 59%. Raised CEA levels were found significantly more frequently in intrathoracically localized tumors than in cervical cancers. Patients surviving less than 6 months showed a higher rate of elevated CEA assays than those who survived 6 to 18 months. No certain correlation was established between tumor marker elevation and tumor stage or tumor differentiation.