Monoclonal antibodies against gastrointestinal tumour-associated antigens isolated as monosialogangliosides

Predictive Value of the Total Bilirubin and CA50 Screened Based on Machine Learning for Recurrence of Bladder Cancer Patients

Purpose

Recurrence is the main factor for poor prognosis of bladder cancer. Therefore, it is necessary to develop new biomarkers to predict the prognosis of bladder cancer. In this study, we used machine learning (ML) methods based on a variety of clinical variables to screen prognostic biomarkers of bladder cancer.

Patients and Methods

A total of 345 bladder cancer patients were participated in this retrospective study and randomly divided into training and testing group. We used five supervised clustering ML algorithms: decision tree (DT), random forest (RF), adaptive boosting (AdaBoost), gradient boosting machine (GBM), and extreme gradient boosting (XGBoost) to obtained prediction information through 34 clinical parameters.

Results

By comparing five ML algorithms, we found that total bilirubin (TBIL) and CA50 had the best performance in predicting the recurrence of bladder cancer. In addition, the combined predictive performance of the two is superior to the performance of any single indicator prediction.

Conclusion

ML technology can evaluate the recurrence of bladder cancer. This study shows that the combination of TBIL and CA50 can improve the prognosis prediction of bladder cancer recurrence, which can help clinicians make decisions and develop personalized treatment strategies.

Tumor biomarkers for diagnosis, prognosis and targeted therapy

Tumor biomarkers, the substances which are produced by tumors or the body's responses to tumors during tumorigenesis and progression, have been demonstrated to possess critical and encouraging value in screening and early diagnosis, prognosis prediction, recurrence detection, and therapeutic efficacy monitoring of cancers. Over the past decades, continuous progress has been made in exploring and discovering novel, sensitive, specific, and accurate tumor biomarkers, which has significantly promoted personalized medicine and improved the outcomes of cancer patients, especially advances in molecular biology technologies developed for the detection of tumor biomarkers. Herein, we summarize the discovery and development of tumor biomarkers, including the history of tumor biomarkers, the conventional and innovative technologies used for biomarker discovery and detection, the classification of tumor biomarkers based on tissue origins, and the application of tumor biomarkers in clinical cancer management. In particular, we highlight the recent advancements in biomarker-based anticancer-targeted therapies which are emerging as breakthroughs and promising cancer therapeutic strategies. We also discuss limitations and challenges that need to be addressed and provide insights and perspectives to turn challenges into opportunities in this field. Collectively, the discovery and application of multiple tumor biomarkers emphasized in this review may provide guidance on improved precision medicine, broaden horizons in future research directions, and expedite the clinical classification of cancer patients according to their molecular biomarkers rather than organs of origin.

Serum CA50 levels in patients with cancers and other diseases

Carbohydrate antigen 50 (CA50) is initially reported as a cancer-specific antigen expressed on the surface of human colorectal Colo-205 cancer cells. Subsequently, increased serum CA50 levels are observed in patients not only with colorectal cancers but also other types of cancers. Eventually, serum CA50 is measured clinically as a cancer biomarker. However, serum CA50 level does not always increase in cancer patients but does increase in patients suffering from nonneoplasm diseases, which indicates that serum CA50 is not produced by cancer cells exclusively. Therefore, the serum CA50 levels in patients suffering different types of diseases should be systematically compared in order to comprehend the molecular nature of serum CA50 as a biomarker. In our current study, we measured and analyzed serum CA50 levels from 2113 patients with 14 clinically defined diseases with at least 30 independent tests for each disease in addition to 13,997 serum samples from individuals who attend their annual physical examination as healthy controls. Based on the mean, median, and -Log₁₀p values, we found that patients suffering from pancreatic cancer, cirrhosis, pancreatitis, lung cancer, type 2 diabetes mellitus, and colon cancer had highest levels of serum CA50 while patients suffering from coronary heart disease, gastric cancer, and rectum cancer showed comparable serum CA50 levels to that of healthy controls. Moreover, patients with osteoporosis, anemia, or gastritis had lower serum CA50 levels than that of healthy controls. Furthermore, healthy individuals older than 65 years old had increased serum CA50 levels compared with that of healthy controls. Taken together, these data suggest that serum CA50 is likely to be a system malfunction biomarker, and the serum CA50 levels could be used as diagnostic biomarkers not only for cancers but also for other nonneoplasm diseases.

CA242 as a biomarker for pancreatic cancer and other diseases

CA242 is a sialic acid-containing carbohydrate antigen attached to core proteins/lipids detected on the cell surface or in serum. Increased serum levels of CA242 have been used clinically as diagnostic biomarkers for pancreatic, colorectal, and other cancers. Since CA242 is overexpressed in malignant tumor tissues compared to that in normal tissues, it is believed that serum CA242 is a product of cancer cells. Thus far, the serum CA242 levels in patients suffering from different types of cancer and noncancerous diseases have not been systematically compared. In our current study, we acquired data of serum CA242 levels from 34,680 patients with 27 clinically defined diseases and from healthy controls (1317) in the clinical laboratory of our hospital over the past 5 years. The mean, median, and -log₁₀p values were calculated. Our data showed that patients with pancreatic cancer, cervical cancer, and lymphoma had the highest median values of serum CA242, which were followed by esophagus cancer, colon cancer, ovarian cancer, type 2 diabetes mellitus, rectal cancer, coronary heart disease, breast cancer, diabetic nephropathy, acute myocardial infarction, and 15 other types of diseases compared to that of healthy controls. In contrast, patients suffering from sequela of brain damage and anemia had statistically lower median values than healthy controls. Based on the -log₁₀p values, the increased serum CA242 levels could be used not only for diagnosis of pancreatic and other cancers, but also for diagnosis of type 2 diabetes mellitus and coronary heart disease, suggesting CA242 might be a systemic malfunction biomarker associated with cancers and other chronic diseases.

Tumor Markers in Pancreatic Cancer: A Comparative Clinical Study between CEA, CA 19-9 and CA 50

Seventy-eight patients were evaluated to ascertain the usefulness of markers CA 19-9 and CA 50 in diagnosing pancreatic cancer, using a less specific marker (CEA) as reference. Three groups were considered: a) 36 controls; b) 22 patients with benign obstructive jaundice; c) 20 patients with pancreatic cancer. Preoperative blood samples were obtained to ascertain CEA (E.I.A.), CA 19-9 (R.I.A.) and CA 50 (T.R.-F.I.A.). Serum concentrations of the various markers were significantly higher for patients with pancreatic cancer in comparison with the other groups, at cut-offs of l0ng/ml (CEA), 100ng/ml (CA 19-9) and 170 U/ml (CA 50). The sensitivity of CA 19-9 (94%) and CA 50 (88%) was much greater than that of CEA (30%). The specificity of the three markers in patients with pancreatic cancer, with respect to the control group, was 100% and this figure is reduced with respect to the group suffering from benign obstructive jaundice (CEA: 90%; CA 19-9: 88% and CA 50: 87%). Diagnostic results (sensitivity, specificity, positive predictive value (P.P. V.) and negative predictive value (N.P. V.)) did not significantly increase with respect to CA 19-9 and CA 50 when considered individually. It is concluded that the serum concentrations of CA 199 and CA 50 showed high sensitivity and specificity as markers of pancreatic cancer with respect to the other groups, pointing towards clinical routine clinical use of both markers. In addition, a comparative study of the literature has been made and prospects for short-term development and concrete applications for early and reliable diagnosis have been highlighted.

MCA in Patients with Breast Cancer: Correlation with CEA and CA15-3

MCA serum levels were determined in 27 healthy subjects, 136 with benign pathology (42 breast) and in 289 patients with cancer (247 active). The last group includes 223 patients with breast cancer (96 without metastases, 89 with metastases and 38 no-evidence of disease). CEA and CA15-3 serum levels were determined in all the patients with breast diseases.

The mean levels of MCA were 4.7 + 2.4 U/ml in the control group, considering less than 11 U/ml as normal. MCA values were abnormal in 15.4 % of patients with benign pathology, mainly in those with liver cirrhosis (8/20) and lung diseases (4/20). In the majority of these cases, the rise was only moderate, lower than 15 U/ml in 97.5% of patients. In malignant diseases, important increments were found in breast cancer (19.8% Mo, 77.5% M1) and ovarian cancer stages III–IV (44.4%). When we compared MCA serum levels with CA15-3 and CEA in breast pathology, a similar specificity was observed: 92.3%, 92.3% and 100% in cases with benign pathology and 92.1%, 94.7%, and 97.4% in NED patients, respectively. MCA and CA15-3 sensitivity was similar in breast cancer without metastases (19.8%) and lower for CEA (16.7%). In patients with breast cancer without metastases, we found a relation between positivity of these tumor markers and prognostic factors (tumor size, nodal involvement). The disease free interval in patients with locoregional breast cancer was shorter in cases with abnormal presurgical levels of some of the tumor markers, but only the difference from MCA was significant (p < 0.02). Inpatients with metastases the sensitivity was about 77.5%, 70% and 65.1% respectively for MCA, CA15-3 and CEA. Sensitivity using the three tumor markers was not significantly better than with only two of them

Tumor Markers in the Diagnosis, Monitoring and Therapy of Pancreatic Cancer: State of the Art

The present review focuses on the utility of serum tumor markers in screening, diagnosis, prognosis and monitoring of pancreatic cancer. Serum determination of all tumor markers studied offers no help in screening or early diagnosis of pancreatic cancer. For diagnosis, blood group-related antigens, in particular CA 19-9, are considered the best indicators of this neoplasm. However, as occurs with other glycoproteic tumor markers, the circulating levels of CA 19-9 are significantly influenced by jaundice, probably because its liver metabolism is reduced. Therefore, the finding of elevated CA 19-9 levels in jaundiced patients has to be evaluated with caution. Since pancreatic cancer recurrences are not susceptible to treatment, the clinical role of widespread use of tumor marker determination in follow-up programs is limited and calls for a critical evaluation.

Span-1 and CA19-9 as Predictors of Early Recurrence and Lymph Node Metastasis for Patients with Invasive Pancreatic Cancer after Pancreatectomy

Because pancreatic cancer is a disease with a dismal prognosis due to the high rate of early recurrence even after curative surgery, selecting the most effective treatment in an individual requires pre-operative assessment of the tumor characteristics, including the potential for early recurrence. The study cohort included 84 patients undergoing surgical resection of pancreatic cancer. Univariate and multivariate analyses were conducted to identify the risk factors for early recurrence within six months after curative resection. Early recurrence was associated with a platelet-lymphocyte ratio ≥0.23 ( P = 0.04), carbohydrate antigen 19-9 (CA19-9) ≥200 ( P = 0.01), and S-pancreas-1 antigen (Span-1) ≥37 ( P = 0.0004) by univariate analysis. Multivariate analysis identified CA19-9 ≥200 and Span-1 ≥37 as independent risk factors for early recurrence. Patients with both risk factors had a significantly higher rate of lymph node metastasis than those with no or one risk factor. Span-1 ≥ 37 and CA19-9 ≥ 200 are independent risk factors for early recurrence in patients who underwent surgical resection, and the combination of Span-1 ≥37 and CA19-9 ≥200 is a useful indicator of lymph node metastasis.

Generation of monoclonal antibody MS17-57 targeting secreted alkaline phosphatase ectopically expressed on the surface of gastrointestinal cancer cells

Background

Therapeutic antibody development is one of the fastest growing areas of the pharmaceutical industry. Generating high-quality monoclonal antibodies against a given therapeutic target is crucial for successful drug development. However, due to immune tolerance, making it difficult to generate antibodies using conventional approaches.

Methodology/Findings

Mixed four human gastric cancer (GC) cell lines were used as the immunogen in A/J mice; sixteen highly positive hybridoma colonies were selected via fluorescence-activated cell sorting-high throughput screening (FACS-HTS) using a total of 20,000 colonies in sixty-seven 96-well plates against live cells (mixed human GC cells versus human PBMC controls). MS17-57 and control commercial Alkaline Phosphatase (ALP) mAbs were used to confirm the target antigens (Ags), which were identified as ALPs expressed on the GC cell surface through a combination of western blot, immunoprecipitation and mass spectrometry (MS).

MS identified the Ags recognized by MS17-57 to be two variants of a secreted ALP, PALP and IALP (Placental and intestinal ALP). These proteins belong to a hydrolase enzyme family responsible for removing phosphate groups from many types of molecules. Immunofluorescence staining using MS17-57 demonstrated higher staining of gastrointestinal (GI) cancer tissues compared to normal GI tissues (P<0.03), and confirmed binding of MS17-57 to be restricted to a functional epitope expressed on the cancer cell surface. Proliferation assays using the PALP/IALP-expressing GC cell lines demonstrated that MS17-57 inhibited cell growth by 32±8%. Transwell cell migration assays documented that MS17-57 can inhibit PALP/IALP-expressing GI cancer cell migration by 25±5%. MS17-57 mAb inhibited tumor growth in nude mice.

Conclusions

Our findings indicate that PALP and IALP can be ectopically expressed on extracellular matrix of GI cancers, and that MS17-57 directed against PALP/IALP can inhibit GI cancer cells growth and migration invitro and invivo. This investigation provides an example of identification of cancer biomarkers representing promising therapeutic targets using mAb generated through a novel HTS technology.

Semisynthetic Maytansine Analogues for the Targeted Treatment of Cancer

Maytansine, a highly cytotoxic natural product, failed as an anticancer agent in human clinical trials because of unacceptable systemic toxicity. The potent cell killing ability of maytansine can be used in a targeted delivery approach for the selective destruction of cancer cells. A series of new maytansinoids, bearing a disulfide or thiol substituent were synthesized. The chain length of the ester side chain and the degree of steric hindrance on the carbon atom bearing the thiol substituent were varied. Several of these maytansinoids were found to be even more potent in vitro than maytansine. The targeted delivery of these maytansinoids, using monoclonal antibodies, resulted in a high, specific killing of the targeted cells in vitro and remarkable antitumor activity in vivo.

Squamous Cell Carcinoma Antigen Isoforms in Serum from Cervical Cancer Patients

Squamous cell carcinoma antigen (SCCA) is a serological marker of squamous cell carcinomas (SCC). To study whether any of the SCCA isoforms would provide additional and more specific/sensitive clinical information than total SCCA, immunoassays specific for the different forms of SCCA (free SCCA2, total SCCA2, total SCCA1 and total SCCA) were developed. SCCA isoforms were determined before therapy and in follow-up samples from patients with cervical cancer and in serum samples from healthy females. Serum samples from patients with benign skin diseases (psoriasis and eczema) were also selected based on elevated SCCA levels. Rising levels of SCCA1 and SCCA2 were seen in patients with recurrence or progressive disease at the end of the study. The rise in SCCA2 was usually more prominent than that in SCCA1. The dominating serological form of SCCA was free SCCA2 both in healthy controls and in patients with cervical cancer. Both SCCA1 and SCCA2 were elevated in serum from cervical cancer patients and followed the clinical course of the disease during therapy monitoring. SCCA2 did not show improved tumor specificity as compared to SCCA1. A larger study is however necessary to make firm conclusions.

Immunohistochemical study of type-1 blood antigen expressions in thyroid tumors: the significance for papillary carcinomas

Immunohistochemical expressions of type 1 blood group antigens were studied for 95 cases of thyroid tumors, including 29 follicular adenomas, 23 follicular carcinomas, and 43 papillary carcinomas, applying monoclonal antibodies against DU-PAN-2, CA19-9, Lewis(a) (Le(a)), and Lewis(b) (Le(b)). Normal thyroid tissue invariably failed to express all four antigens. In follicular adenomas, DU-PAN-2 and CA19-9 were focally expressed in 7% and 21% of cases, and in follicular carcinomas, CA19-9 expression was limited to one case (4%); all cases were negative for DU-PAN-2. No or little expression of Le(a) or Le(b) was observed in these follicular tumors. In contrast, DU-PAN-2, CA19-9, Le(a), and Le(b) were expressed in 98%, 84%, 33%, and 49% of 43 papillary carcinomas, respectively. The positive stainings were observed mainly on the luminal surface of the tumor cells. The number of tumor cells that expressed DU-PAN-2 generally was greater than that of tumor cells that expressed CA19-9, Le(a), or Le(b). There was no significant difference in antigen expressions in female papillary carcinomas between subjects who were younger and older than 50 years old. The results suggest that DU-PAN-2 would be a useful immunohistochemical marker for distinguishing papillary carcinomas from follicular tumors. These immunohistochemical profiles imply the following: the activity of alpha2-3 sialyltransferase, a specific glycosyltransferase, would be more strongly enhanced in papillary carcinomas than in follicular tumors; the antigen expressions in papillary carcinomas may not be related to the alteration of the female sex hormone environment.

Detection of CD43 (leukosialin) in colon adenoma and adenocarcinoma by novel monoclonal antibodies against its intracellular domain

CD43 is a leukocyte-associated sialoglycoprotein which is also expressed in human colon adenoma and carcinoma. To obtain monoclonal antibodies (MAbs) that would react with CD43 in a glycosylation-independent way, antibodies were raised against a peptide corresponding to a portion of the CD43 cytoplasmic domain. Hybridomas were screened on paraffin sections from CD43-positive colon tumours. The reactivity of the antibodies with CD43 was verified by Western blot analysis of lysate of CHO cells transfected with human CD43 cDNA and by immunoprecipitation of lysates from CD43+ cell lines. Epitope mapping of antibodies was done using overlapping heptameric peptides. A detailed characterisation of one of the novel antibodies (CD43-3A1) is presented. This antibody reacts with the CD43 protein regardless of its glycosylation in Western blot analysis, immunoprecipitation and immuno-histochemistry of paraffin sections. Immuno-histochemical analysis of paraffin sections from colon adenoma and carcinoma tissues as well as colon cancer cell lines revealed that CD43 was predominantly localised intracellularly, in contrast to leukocyte-type cells. The MAb reacted more efficiently with paraffin-embedded colon adenoma and carcinoma cells than previously characterised CD43-specific antibodies. This should facilitate the evaluation of a potential role of CD43 during cancer development.

Clinical aspects of altered glycosylation of glycoproteins in cancer

Alteration of the expression of carbohydrate structures is frequently observed in tumor cells. This review summarizes the different changes of O- and N-linked glycoproteins observed in cancer cells, the impact of the tumor-related carbohydrate phenotypes on the clinical outcome of the cancer disease, and the various ways in which carbohydrate structures can interact with different carbohydrate-detecting adhesion molecules, selectins, and sialoadhesins. Various ways of inhibiting the formation of cell adhesion-engaged carbohydrates on the cell surface, or inhibiting the binding are discussed. Carbohydrate structures which are in clinical use as circulating tumor markers and the effect of genotypes on tumor marker concentrations are reviewed.

Clinical aspects of altered glycosylation of glycoproteins in cancer

Alteration of the expression of carbohydrate structures is frequently observed in tumor cells. This review summarizes the different changes of O- and N-linked glycoproteins observed in cancer cells, the impact of the tumor-related carbohydrate phenotypes on the clinical outcome of the cancer disease, and the various ways in which carbohydrate structures can interact with different carbohydrate-detecting adhesion molecules, selectins, and sialoadhesins. Various ways of inhibiting the formation of cell adhesion-engaged carbohydrates on the cell surface, or inhibiting the binding are discussed. Carbohydrate structures which are in clinical use as circulating tumor markers and the effect of genotypes on tumor marker concentrations are reviewed.

Autoantibodies in the serum of patients with gastric cancer: their prognostic importance

To evaluate the presence in serum and the clinical relevance of several antinuclear autoantibodies, we investigated 31 patients with initially diagnosed gastric cancer and 40 age-matched healthy controls. Autoantibodies against ssDNA, dsDNA, cardiolipin, actin, myosin, tropomyosin, GM1, GD1b and GT3 gangliosides, were detected with an enzyme-linked immunoassay (ELISA). Anti-ssDNA, anti-actin, anti-GM1 and anti-GD1b antibodies were detected in the serum of 11 (p = 0.001), 8 (p = 0.02), 11 (p = 0.001), and 9 (p = 0.008) patients with gastric cancer, respectively. There was no significant difference between patients with cancer and the control group, as far as the other autoantibodies were concerned. Most of the patients (90%) had autoantibodies against at least one of the antigens examined. Patients with anti-ssDNA, anti-actin, anti-GM1 and anti-GD1b antibodies were less likely to survive than the patients being negative to the above autoantibodies: the figures are 1 of 11 (9%) compared with 4 of 20 (20%); 1 of 8 (13%) compared with 5 of 23 (22%); 1 of 11 (9%) compared with 4 of 20 (20%); and 1 of 9 (11%) compared with 4 of 22 (18%), respectively. Our findings suggest that 4 of the 9 autoantibodies that we assayed are significantly more likely to be found in serum of patients with gastric cancer, indicating that the immune system has a role in the process of the malignant disease. If our results are confirmed by forthcoming studies, some of the immunological variables that we examined could be used as markers of prognostic value in patients with gastric cancer.

Novel monoclonal antibodies to putative selectin carbohydrate ligands that inhibit selectin binding to myeloid cells

Four newly developed monoclonal antibodies (MAbs) are characterized using flowcytometry, enzyme-linked immunoadsorbent assay (ELISA), immunoprecipitation and Western blots, carbohydrate epitope mapping, glycosidase cleavage, and competition binding assays. Their effects on selectin binding to myeloid cells was tested. These MAbs react only with myeloid cells. MAbs CI-1, BU60, and HIM95 recognize epitopes expressed by CD11/CD18 (beta2) integrins, while HI247 and CSLEX1 do not. The epitopes require Lewis x [Galbeta1-4 (Fucalpha1-3)GlcNAc] based on reactivity with oligosaccharide-polyacrylamide-biotin or oligosaccharide-BSA conjugates. MAb HI247 recognizes a related structure, sialyl-Lewis x, NeuAcalpha2-3GaLbeta1-4(Fucalpha1-3)GlcNAc. The three MAbs against Lewis x show some minor differences in their reactivity such as recognizing their antigens on CD11/CD18 integrins after endo-beta-galactosidase treatment and recognizing free Lewis x. The hydroxyl group on C-3 of the terminal galactose is important for recognition by MAb CI-1, BU60, and HIM95 as its substitution with sulfo group of sialic acid abolishes the binding of these MAbs. The C-3 sialic acid is crucial for the binding of MAb HI247. Its replacement by sulphate or its cleavage by sialidase eliminates recognition by this MAb. MAbs HI247 and CSLEX-1 did not react in ELISA with immobilized CD11/CD18, suggesting that the majority of sialyl Lewis x on CD11/CD18 molecules may have sialic acid 6-linked rather than 3-linked to galactose. Unexpectedly, MAb BU60 inhibited binding of P-selectin mu chain chimera to HL-60 or U937 cells, while CI-1, HIM95 and three other defined anti-Lewis x MAbs (6C7, M6-1 and LeuM1) did not. MAb HI247 inhibited binding of both E- and P-selectin chimeras to these cell lines more effectively than several characterized MAbs (CSLEX-1, FH6, HECA-452) to sialyl Lewis x and related oligosaccharides. Certain combinations of these anticarbohydrate MAbs had additive inhibitory effects on selectin binding, suggesting a potential application of these new MAbs in cell adhesion/migration and tumor metastasis studies.

CEA, CA 19-9, and CA-50 in monitoring gastric carcinoma

This study was conducted to investigate the clinical utility of CEA, CA 19-9, and CA-50 in the diagnosis, monitoring, and prognosis of 62 gastric carcinoma patients having either adjuvant or palliative chemotherapy. Patients were divided in two groups: group A included patients treated on an adjuvant basis following a curative resection of gastric cancer, and group B included patients with residual disease post surgery or patients with inoperable tumor or generalized disease. Serum marker levels were measured in a prospective study just before the initiation of chemotherapy and before each course during chemotherapy. In group A, CEA was positive in 2/25 (8%) patients, CA 19-9 in 1/25 (4%), and CA-50 in 1/25 (4%). In group B the sensitivity of CEA was 48.6% (18/37 patients), of CA 19-9 64.9% (27/37 patients), and of CA-50 70.3% (26/37) patients. There was a significant correlation between the CA 19-9 and CA-50 levels in both groups. No correlation was found between the sensitivity or the absolute initial marker levels and the tumor's differentiation or extent of disease. In group A the only patient with initially elevated CA 19-9 and CA-50 values relapsed early while he was on adjuvant chemotherapy. It was also found that the rising final CA 19-9 and CA-50 values at the end of chemotherapy were correlated with an increased incidence of relapse, but not with the disease-free interval. In group B the initially low marker levels showed a trend to predict a favorable outcome of treatment. There was no statistically significant correlation between the marker titers before each course and response to chemotherapy. It is concluded that the comeasurement of CA 19-9 and CA-50, and to some degree of CEA, is justifiable for gastric cancer. The estimation of CA 19-9 and CA-50 may be useful for early detection of recurrence after curative surgery and adjuvant chemotherapy. In advanced or recurrent gastric cancer, the estimation of either CA 19-9 or CA-50 and CEA serum values may help in checking the prognosis, determining the efficacy of palliative treatment modalities, and recognizing recurrences.

Urotherapy for patients with cancer

Cancer cells release various antigens, some of which appear in the urine. Oral autourotherapy is suggested as a new treatment modality for cancer patients. It will provide the intestinal lymphatic system with the many tumor antigens against which antibodies may be produced. These antibodies may be pierced through the blood stream and attack the tumor and its cells.

Tumour marker CA 50 levels compared to signs and symptoms in the diagnosis of pancreatic cancer

The diagnostic merits of CA 50 and of symptoms indicating pancreatic cancer (pain, jaundice, weight loss, malabsorption) were compared prospectively in 512 consecutive patients. Among the final diagnoses were: exocrine pancreatic cancer, 175; periampullary cancer, 44; other gastrointestinal cancer, 45; and chronic pancreatitis, 64 cases. The suspected diagnoses based on symptoms and signs were correct in 80% of the patients with exocrine pancreatic cancer, in 78% with periampullary, in 76% with other gastrointestinal cancer and in 90% with chronic pancreatitis. CA 50 was pathological in 96% of the cases with exocrine pancreatic cancer, in 70% with periampullary, in 78% with other gastrointestinal malignancies and in 36% with chronic pancreatitis. The sensitivity was 96%, specificity 48%, positive prediction 49% and negative prediction 96%, depending on cut-off level. The single CA 50 value was comparable to symptoms and signs regarding sensitivity and negative prediction. In 28 of 42 cases incorrectly clinically classified, CA 50 alone indicated a benign or malignant diagnosis. If both the modalities 'signs and symptoms' and CA 50 were combined, the sensitivity was 91%, the specificity 92%, the positive prediction 86% and the negative prediction 95%. The initial CA 50 value can help to indicate in which patients a pancreatic malignancy should be suspected.

Diagnostic value of CA 19-9 in patients with pancreatic cancer and nonspecific gastrointestinal symptoms

Serum expression of the tumor marker CA 19-9 was studied in 2119 patients. The discriminating capacity between benign and malignant disease was high for CA 19-9, especially in patients with pancreatic cancer (n = 347). The sensitivity of CA 19-9 was 85%. In patients who were Lewis blood type positive, the sensitivity increased to 92%. CA 19-9 levels were significantly lower in patients with resectable tumors (n = 126) than in those with unresectable tumors (n = 221, P < 0.0001; sensitivity 74% vs. 90%). CA 19-9 levels dropped sharply after resection but normalized in only 29%, 13%, and 10% of patients with stage I, II, and III tumors, respectively. In unresectable tumors no significant decrease in CA 19-9 levels after laparotomy or bypass surgery was found. Among patients with the same tumor stage, the median survival time in those whose CA 19-9 levels returned to normal after resection was significantly longer than in those who had postoperative CA 19-9 levels that decreased but did not return to normal (stage I, 33 months vs. 11.3 months; stage II, 41 months vs. 8.6 months; and stage III, 28 months vs. 10.8 months). In patients with recurrent disease, 88% had an obvious increase in CA 19-9 levels. CA 19-9 measurement is a simple test that can be used for diagnosis, for evaluation of resectability, and for prediction of survival after surgery and recurrences.

Thyroid autoantibodies and thyroid function in patients with pancreatic adenocarcinoma

Pancreatic adenocarcinoma (PA) patients often present high serum titres of several autoantibodies including autoantibodies against beta-islet cells and insulin. In the present study we examined with an hemagglutination method the sera of 33 patients with PA for the presence of both anti-mitochondrial and anti-thyroglobulin antithyroid autoantibodies (ATA). Twenty-six surgical patients with other non-malignant gastrointestinal tract (GI) disease (chronic pancreatitis or hernia) and 40 healthy volunteers were used as controls. Eight of the 33 PA patients were found to have ATA autoantibodies, whereas only one patient with chronic pancreatitis and 2 normal individuals had high serum ATA titres. The difference between the PA patients and either of the control groups was statistically significant (p < 0.05). The production of autoantibodies could be attributed to impaired immunoregulation caused by the malignant cells.

Antigenic determinants of prostate-specific antigen (PSA) and development of assays specific for different forms of PSA

Monoclonal antibodies were raised against prostate-specific antigen (PSA) by immunization with purified free PSA, i.e. not in complex with any protease inhibitor (F-PSA) and PSA in complex with alpha1-anti-chymotrypsin (PSA-ACT). Epitope mapping of PSA using the established monoclonal antibody revealed a complex pattern of independent and partly overlapping antigenic domains in the PSA molecule. Four independent antigenic domains and at least three partly overlapping domains were exposed both in F-PSA and in the PSA-ACT complex, while one antigenic domain was specific for F-PSA. The different domains contained both continuous and discontinuous epitopes. The combination of antibodies recognizing antigenic domains exposed both in F-PSA and PSA-ACT made it possible to develop several highly sensitive sandwich immunoassays for determination of total PSA, i.e. F-PSA + PSA-ACT, with the same molar response for F-PSA and PSA-ACT. Assays specific for F-PSA (cross-reactivity between F-PSA and PSA-ACT < 1%) were developed by the combination of antibodies recognizing epitopes exposed only in F-PSA and antibodies recognizing epitopes exposed both in F-PSA and PSA-ACT.

CA 19-9 serum course and prognosis of pancreatic cancer

CONCLUSION

CA 19-9 measurement is a simple test that can be used for diagnosis as well as for prediction of resection, survival rate after surgery, and recurrences.

METHODS

Serum expression of the tumor marker CA 19-9 was studied in 2119 patients.

RESULTS

The discriminating capacity between benign and malignant disease was high for CA 19-9, especially in patients with pancreatic cancer (n = 347). The sensitivity of CA 19-9 was 85%. In patients who were Lewis blood type positive, the sensitivity increased to 92%. CA 19-9 levels were significantly lower in patients with resectable tumors (n = 126) than in those with unresectable tumors (n = 221, p < 0.0001) (sensitivity 74 vs 90%). CA 19-9 dropped sharply after resection, but normalized only in 29, 13, and 10% in patients with stage I, II, and III, respectively. In unresectable tumors no significant decrease of CA 19-9 after laparotomy or bypass operation was found. In patients of the same tumor stage, the median survival time in those whose CA 19-9 levels returned to normal after resection was significantly longer than in those with postoperative CA 19-9 levels that decreased, but did not return to normal (in stage I, 33 vs 11.3 mo, in stage II, 41 vs 8.6 mo, and in stage III, 28 vs 10.8 mo). In patients with recurrent disease, 88% had an obvious rise in CA 19-9 levels.

Oncofetal expression of blood group-related antigen on morules in thyroid carcinoma

Morule formation in association with characteristic biotinrich 'optically clear nuclei' were found in 7 of 2514 cases of thyroid carcinoma. The seven patients were all young females aged from 20 to 36 years who were suffering from either papillary carcinoma (six cases) or follicular carcinoma (one case). The ABH (O) blood group (BG) types were A in three, AB in two and H(O) in two patients. Immunohistochemical study revealed that ABH(O) and Lewis BG antigens were expressed more specifically on morules than on ordinary neoplastic cells of papillary or follicular carcinoma. Lewis BG antigens tested in the present study were as follows: CA50, CA19-9, stage-specific embryonic antigen 1 (SSEA-1), and sialyl SSEA-1. Ulex europaeus agglutinin I (UEA-I) histochemistry showed a positive reaction on all the morules of blood groups A and H(O) patients, but yielded completely negative results on the morules of type AB patients. Sequential digestion by neuraminidase and alpha-galactosidase unmasked the reactivity for UEA-I even on the morules of type AB patients. The consistent reactivity for UEA-I on the morules seemed to be related to specific expression of BG antigens, which were characterized as oncofetal expression. It is suggested that the morules in thyroid carcinoma might be a kind of fetal component induced by the differentiation of the neoplastic cells to the stage of immature embryonic cells.

Eradication of large colon tumor xenografts by targeted delivery of maytansinoids

The maytansinoid drug DM1 is 100- to 1000-fold more cytotoxic than anticancer drugs that are currently in clinical use. The immunoconjugate C242-DM1 was prepared by conjugating DM1 to the monoclonal antibody C242, which recognizes a mucin-type glycoprotein expressed to various extents by human colorectal cancers. C242-DM1 was found to be highly cytotoxic toward cultured colon cancer cells in an antigen-specific manner and showed remarkable antitumor efficacy in vivo. C242-DM1 cured mice bearing subcutaneous COLO 205 human colon tumor xenografts (tumor size at time of treatment 65-130 mm3), at doses that showed very little toxicity and were well below the maximum tolerated dose. C242-DM1 could even effect complete regressions or cures in animals with large (260- to 500-mm3) COLO 205 tumor xenografts. Further, C242-DM1 induced complete regressions of subcutaneous LoVo and HT-29 colon tumor xenografts that express the target antigen in a heterogeneous manner. C242-DM1 represents a new generation of immunoconjugates that may yet fulfill the promise of effective cancer therapy through antibody targeting of cytotoxic agents.

Distinct sub-populations of carcinoma-associated MUC1 mucins as detected by the monoclonal antibody 9H8 and antibodies against the sialyl-Lewis a and sialyl-Lewis x epitopes in the circulation of breast-cancer patients

The cancer-associated epitope defined by the monoclonal antibody (MAb) 9H8 was shown to be closely related to the T antigen (Thomsen-Friedenreich antigen) by its sensitivity to 0-glycanase treatment of a mucin glycopeptide known to express this epitope. The reactivity with this glycopeptide increased upon neuraminiclase treatment, and among several MAbs tested for ability to block binding of the 9H8 antibody, the one specific for the T antigen was the most efficient. Out of 41 serum samples from breast-cancer patients, 11 showed elevated levels of the 9H8 epitope, and several sera also showed elevated levels of the cancer-associated carbohydrate epitopes sialyl-Lewis a and sialyl-Lewis x. By the use of antibodies specific for the MUC1 apoprotein (Ma552 and HMFG-2) it could be shown that these epitopes were attached to the MUC1 apoprotein in at least 4 of the cases. By combining antibodies specific to 9H8, sialyl-Lewis a and sialyl-Lewis x in catcher and tracer positions in several types of immunofluorometric assays, it was shown that the 9H8 epitope was rarely co-expressed with sialyl-Lewis a or sialyl-Lewis x epitopes an the same molecule, though all were expressed on MUC1 mucins. In fact, they can be considered as mutually exclusive epitopes, suggesting that these sera contained different populations of MUC1 mucins distinguishable by different sets of oligosaccharides. The existence of mutually exclusive carbohydrate epitopes on different MUC1 mucins in one and the same patient should be taken into account when designing immunoassays exploiting MUC1-reactive antibodies.

Autoantibodies against insulin and beta-islet cells in pancreatic adenocarcinoma: a possible explanation for diabetes mellitus

To evaluate the prevalence of autoantibodies against the b-islet cells (ICA) and the molecule of insulin (IAA) in the serum of patients with pancreatic adenocarcinoma (PA), we examined the sera of 36 newly diagnosed pancreatic adenocarcinoma patients for the presence of these antibodies, using an enzyme-linked immuno-assay method. These results were correlated with survival. Ten patients with insulin-dependent diabetes mellitus (IDDM) and 21 healthy volunteers were evaluated as age-matched controls. Twenty out of 36 (57%) PA patients were found to have detectable ICA autoantibodies and 17 (48%) PA patients had detectable IAA antibodies. Five out of 10 (50%) and 3 out of 10 (30%) IDDM patients had ICA and IAA antibodies, respectively. None of the healthy volunteers was positive for either of the autoantibodies examined. The difference was statistically very significant and the presence of high serum titers of both autoantibodies was associated with a worse outcome for these patients than for those without such autoantibodies. Our data suggest that the high incidence of diabetes mellitus in patients with PA may be attributed to the presence of these autoantibodies. Further clinical studies are needed to establish the above autoantibodies as prognostic markers of pancreatic cancer.

Alpha 2-->3sialyltransferase associated with the synthesis of CA 19-9 in colorectal tumors

BACKGROUND

A novel assay method specific for alpha 2-->3sialyltransferase that seems to be responsible for the synthesis of CA 19-9 antigen was developed and the levels of the enzyme in colorectal tumor tissues were measured and compared with the levels of alpha 1-->4fucosyltransferase and the CA 19-9 antigen.

METHODS

Lacto-N-biose I (Gal beta 1-->3GlcNAc beta, Lewis(c) [Le(c)]) and 6-O-methyl-Le(c) (Gal beta 1-->3[6OMe]GlcNAc beta) were synthesized and covalently attached to bovine serum albumin (BSA). These two substrates were incubated with extracts from colorectal tissues in the presence of cytidine 5'-monophospho-N-acetylneuraminic acid (CMP-NeuAc) and their resulting products were detected by a sequential use of anti-BSA monoclonal antibody-coated beads and 125I-labelled anti-sialylated Le(c) antibody. Levels of alpha 2-->3sialyltransferase and alpha 1-->4fucosyltranferase activities and CA 19-9 antigen were measured in the extracts from colorectal tumors and their adjacent normal tissues.

RESULTS

6-O-Methyl-Le(c)-BSA showed a strong acceptor activity compared with Le(c)-BSA and was used as a specific acceptor for alpha 2-->3sialyltransferase. Similar elevation patterns alpha 2-->3sialyltransferase activities and CA 19-9 antigen levels were observed in tumor extracts but no clear correlation was present between the level of alpha 1-->4fucosyltransferase activities and CA 19-9 antigen levels were observed in tumor extracts but no clear correlation was present between the level of alpha 1-->4fucosyltransferase activities and CA 19-9 antigen levels in the same extracts.

CONCLUSIONS

The accumulation of CA 19-9 antigen in colorectal tumors might be caused mainly by the activation of alpha 2-->3sialyltransferase but not by that of alpha 1-->fucosyltransferase.

Clinical relevance of serological markers in the detection and follow-up of pancreatic adenocarcinoma

Pancreatic adenocarcinoma is a relatively common malignancy and its incidence is increasing. Prognosis in these patients is poor, and surgery, the only effective treatment, saves only a minority of patients. The number in this small group of patients might be increased by early detection of pancreatic tumours. This review examines the current status of pancreatic tumour associated proteins in the detection of pancreatic cancer. As well as existing markers, the review also reports on newer markers that may offer advantages over existing ones in the detection of pancreatic adenocarcinoma. This is particularly important because recent studies have identified high-risk groups susceptible to pancreatic cancer. Future research in pancreatic cancer should be directed at earlier detection, and tumour markers may play an important role in this process.

Sialyl Tn antigen is an independent predictor of outcome in patients with gastric cancer

The prognostic value of the immunohistochemical expression of Sialyl Tn antigen (STn) was evaluated in 242 patients with gastric carcinoma. Formalin-fixed, paraffin-embedded specimens of gastric adenocarcinomas were stained with the monoclonal antibody C1282, produced by immunization with ovine submaxillary mucin (OSM). Positive immunoreactivity for STn was observed in 149 (62%) patients. The expression of STn did not correlate with stage of disease (TNM), tumour location, presence of lymph-node or distant metastases, histological type, age or gender. STn immunoreactivity correlated strongly with overall survival in univariate analysis. The median survival in the STn-positive group was 21 months, in comparison to 38 months in the STn-negative group. The difference in survival between STn-negative and STn-positive tumours was significant in patients with stage-I cancer, but not in patients with stage-II -III or -IV disease. STn immunoreactivity emerged as an independent prognostic factor in Cox multivariate analysis. It is concluded that the immunohistochemical expression of STn is a good marker in the prediction of survival in patients with stage-I gastric carcinoma.

A secreted mucin carrying sialyl-Lewis a from colon carcinoma cells binds to E-selectin and inhibits HL-60 cell adhesion

Sialyl-Lewis x and a are known as ligands for E-selectin (ELAM-I) involved in leukocyte-endothelial adhesion. L-CanAg (light cancer antigen), secreted by a colon carcinoma cell line COLO 205, is a soluble mucin-type glycoprotein expressing sialyl-Lewis a antigens. L-CanAg was purified from spent culture medium by trichloracetic acid precipitation and Superose 6 gel filtration. With a monoclonal antibody against E-selectin (BBAI) as a positive control, the purified L-CanAg was shown to bind to E-selectin-Fc coated into plastic microtiter wells and to the surface of transiently E-selectin-transfected COS-I cells in a Ca(2+)-dependent way. Immunofluorescent double labelling showed that both BBAI and L-CanAg stained the same cells and morphological co-localization on E-selectin-transfected COS-I cells. Like BBAI, L-CanAg can inhibit leukocyte HL-60 cell adhesion to E-selectin-transfected COS-I cells, and this inhibition can be blocked by a F(ab')2 fragment directed against the sialyl-Lewis a epitope.

125I-labelling of an internally 75Se-labelled monoclonal antibody--biodistribution in tumour-bearing nude mice

A monoclonal antibody, C215, was first internally labelled with 75Se-methionine and then labelled with 125I. The biodistribution of the dual-labelled [125I][75Se]C215 was studied in tumour-bearing nude mice killed 3 days after injection. The biodistribution of the dual-labelled [125I][75Se]C215 was compared with the biodistribution of single-labelled [131I]C215 and [75Se]C215. Iodine-labelled antibodies seem to be damaged during iodination, affecting the disappearance rate and tumour uptake. There were no signs of dehalogenation of circulating antibodies or antibodies taken up in the tumour.

CA 242, a new tumour marker for pancreatic cancer: a comparison with CA 19-9, CA 50 and CEA

The serum expression of a novel tumour marker, CA 242, defined by monoclonal antibody C 242, was studied in 179 patients with pancreatic cancer. The results were compared with CA 19-9, CA 50 and CEA. CA 242 is a carbohydrate closely related, but not identical, to CA 19-9 and CA 50. The overall sensitivity of the CA 242 assay was 74%: 55% in stage I, 83% in stage II-III and 78% in stage IV disease. The specificity calculated from 112 patients with benign diseases was 91%. CA 19-9 had a higher sensitivity of 83%, but the specificity was only 81%. When comparing the markers by receiver operating characteristic analysis, the sensitivities were almost identical at all specificity levels. The CA 242 level was elevated in 7%, 15% and 7% of patients with benign pancreatic, biliary and liver disease respectively. The corresponding figures for CA 19-9 were 19%, 28% and 15% respectively. The sensitivity of CA 242 was higher than that of CA 50 and CEA at all specificity levels. In conclusion, tumour marker CA 242 seems to be a useful diagnostic tool for the diagnosis of pancreatic cancer, and is an alternative to CA 19-9. The advantage of CA 242 over CA 19-9 is its higher specificity when using the recommended cut-off levels of the assays.

The influence of cholestasis on CA 50 and CA 242 in pancreatic cancer and benign biliopancreatic diseases

The tumour markers CA 50 and CA 242 were determined in serum from 70 cholestatic patients--35 with pancreatic cancer and 35 with benign biliopancreatic diseases. Both markers correlated (r = 0.37) with serum bilirubin in all patients. When the patients were subdivided into groups, the only correlation apparent was between CA 50 and bilirubin in patients with benign diseases (r = 0.40). The serum concentrations of both markers were much higher in patients with pancreatic cancer. Serial sampling before and after decompression of the cholestasis showed reduction of CA 50 and CA 242 concurrently with bilirubin and alkaline phosphatases in nine patients with benign disease but unchanged levels in six cancer patients. When the two markers were compared, sensitivity was superior for CA 50 (94% versus 73%), whereas specificity was better for CA 242 (65% versus 34%), as was positive prediction (76% versus 59%), whereas negative prediction was higher for CA 50 (86% versus 61%). Higher cut-off levels yielded better specificity for CA 50 but not for CA 242. Both markers indicate pancreatic cancer irrespective of cholestasis, but moderate elevations occur in some patients with benign disorders.

Immunohistochemical and immunoelectron microscopic study of cytochrome P-450 of human fetal livers (P-450HFLa): implications for an onco-feto-placental enzyme

Cytochrome P-450 of human fetal livers (P-450HFLa) was demonstrated by the avidin-biotin immunoperoxidase technique in tissue samples as follows: human fetal organs, adult livers, human and cynomolgus placenta, and gynecologic organs which were obtained from 40 patients with gynecologic malignancies and 32 patients with benign diseases. P-450HFLa was clearly localized in the cytoplasm and membranes of the hepatocytes, and the fact was confirmed by an immunoelectron microscopic examination. In addition, a semiquantitative assay of staining intensity demonstrated that this enzyme tended to decrease with advancing age. These findings suggest that hepatic P-450HFLa synthesis is inversely proportional to age, and that this enzyme is one of the differentiation antigens. P-450HFLa was also detected immunohistochemically in other fetal organs. The present study thus confirms that P-450HFLa is not specific to the liver and is ubiquitous even in the fetus. Marked positive staining for P-450HFLa was demonstrated in villous syncytiotrophoblasts. In contrast, no positive staining was found in the cynomolgus-monkey placenta, unlike the case for many other placental antigens. These findings lead to the tentative conclusion that P-450HFLa is a feto-placental enzyme peculiar to humans. P-450HFLa was demonstrated to occur very frequently in gynecologic malignancies. The mean positivity rate for all gynecologic malignancies was 85%, while the rate was below 25% for benign gynecologic diseases, indicating that P-450HFLa is one of the onco-feto-placental enzymes. The present study thus suggests that this enzyme could be a promising new tumor marker for gynecologic malignancies.

Receiver operating characteristic (ROC) curve analysis of the tumour markers CEA, CA 50 and CA 242 in pancreatic cancer; results from a prospective study

The serum values of the tumour markers carcinoembryonic antigen (CEA), cancer-associated carboanhydrate antigens CA 50 and CA 242 were evaluated in 193 patients with hepatopancreato-biliary diseases by receiver operating characteristic (ROC) curve analysis in order to compare their diagnostic accuracy in pancreatic cancer (n = 26), and to define optimal cut-off levels for the serum values of these tumour markers in the diagnosis of pancreatic cancer. The ROC analysis showed that all marker tests are considerably sensitive (77-81%) at the specificity level of 80%. The CA 242 test was more sensitive than CEA and CA 50 at high specificity levels (> 0.90) but slightly less sensitive at low specificity levels (< 0.60). The CEA test and CA 50 test performed equally well at high and low specificity levels. According to this study, it would seem optimal to use the cut-off level of 4.1 ng ml-1 for CEA, and the level of 137 U ml-1 for CA 50, since they gave a sensitivity of 77% at the specificity levels of 83% and 84%, respectively. For CA 242 the optimal cut-off level was 21 U ml-1, which gave a sensitivity and specificity of 81%. In conclusion, the results of ROC curve analysis suggest that the CA 242 test has an advantage over CEA and CA 50 because of its higher specificity in pancreatic cancer. In addition, it would seem reasonable to use higher cut-off values than what has been recommended for CEA and CA 50 in the diagnosis of pancreatic cancer, but for CA 242 the recommended cut-off level of 20 U ml-1 seems appropriate.

CA 242 is a new tumor marker for pancreatic cancer

BACKGROUND

The tremendous progress in imaging techniques over the past few years has not resulted in an earlier diagnosis of pancreatic cancer (PC). The search for a noninvasive diagnostic tool, capable of early diagnosis, led to the development of a series of tumor markers. This article discusses the evaluation of the latest one--CA 242--and its comparison with established markers such as CA 19.9, CA 50, and carcinoembryonic antigen (CEA).

METHODS

The markers were tested in preoperative serum samples collected from 300 patients and 30 healthy controls between April 1986 and May 1991. There were 68 patients with ductal carcinoma of the pancreas, 24 with other pancreatic tumors, 57 with acute pancreatitis, 29 with chronic pancreatitis (CP), 90 with benign disease of the upper gastrointestinal tract, and 32 with malignant disease. The test for CA 242 consisted of a DELFIA research kit (WALLAC OY, Turku, Finland) with a cutoff level of 20 U/ml. The other markers were tested with commercially available kits.

RESULTS

Sensitivities for PC in this population, with other malignant neoplasms accounting for 16% of the group, were 66.2%, 70.6%, and 70.6% for CA 242, CA 19.9, and CA 50, respectively (90% specificity level). The best results were achieved with the combination of CA 242 and CA 50, reaching a sensitivity of 75.0%. The differential diagnosis between PC and CP could be made with a sensitivity of 64.7%, 79.4%, and 77.9%, respectively, for the three markers.

CONCLUSIONS

The authors conclude that, on its own, CA 242 does not improve the sensitivities reached with CA 19.9 and CA 50, but the combination does achieve both a higher sensitivity and specificity.

Therapy with 125I-labelled internalized and non-internalized monoclonal antibodies in nude mice with human colon carcinoma xenografts

The therapeutic effects of 125I-labelled (18-97 MBq) monoclonal antibodies (MAb) C-242, C-215 and S-S.1 were studied in nude mice with human colorectal adenocarcinoma tumours. The antibodies were administered 2 or 10-16 days after implantation of the tumour cells. The monoclonal antibody C-242 was internalized into the tumour cells, C-215 was internalized to a lower degree while S-S.1 (unspecific MAb) was not internalized at all. No enhanced therapeutic effect of 125I-C-242 was observed, as a result of Auger electrons, compared with 125I-C-215 and 125I-S-S.1.

Expression of blood group-related antigens in normal and malignant pancreatic tissue correlated with genotype of the patient defined by saliva glycoprotein

BACKGROUND

Seven murine monoclonal antibodies (MoAb) detecting blood group antigens of the Lewis system and their sialylated derivatives were used to define their immunohistochemical distribution in normal and malignant pancreatic tissues. The specific blood group antigens studied included Lewis(a) (Le(a)), Lewisb (Leb), Lewisx (Le(x)), Lewis(y) (Le(y)), sialyl-Lewis(a) (s-Le(a)), sialyl-lacto-N-tetraose (s-LNT), and sialyl-Lewisx (s-Le(x)).

METHODS

The expression of these antigens was analyzed by immunoperoxidase technique in pancreatic tissue of patients with (n = 27) and without (n = 19) pancreatic cancer. The genetic background of their secretor status and their Lewis phenotypes were determined by the enzyme-linked immunosorbent assay using purified salivary glycoprotein and MoAb against eight different blood group-related antigens (Le(a), Leb, Le(x), Le(y), H1, H2, A, B2), and the putative genotypes of the patients were classified as follows: SeLe, Sele, seLe, and sele.

RESULTS

The following results were obtained: (1) In normal pancreas, Le(a), s-Le(a), s-LNT, and s-Le(x) were expressed in ducts, but their expression was restricted to the luminal side of the cytoplasm (cytoplasmic type with positive polarity). Leb and Le(y) showed similar patterns of expression in ducts and some parts of the acinus. In contrast, Le(x) was absent in most cases. (2) Expression of Leb was observed in normal pancreatic ducts in all 46 patients, regardless of their genotypes. Le(a) and s-Le(a) were not expressed in specimens from patients with the seLe and sele saliva phenotypes. (3) In pancreatic cancer, the following antigens were expressed cytoplasmically in the proportion of cases indicated: Le(a) (78%), Leb (85%), Le(x) (33%), Le(y) (44%), s-Le(a) (78%), s-LNT (89%), and s-Le(x) (85%). They also were detected in the surrounding stroma. This pattern of expression is distinct from that found in normal pancreatic tissue. Patients with Sele and sele genotypes did not express Le(a) or s-Le(a), except in one case. (4) Serum levels of carbohydrate antigen 19-9 (CA 19-9) were not elevated in patients with pancreatic cancer with the Sele and sele genotypes but were elevated in most patients with SeLe and seLe genotypes.

CONCLUSION

The overall findings indicate that Lewis-related antigens act as pancreatic tissue-related antigens, depending in part on salivary phenotypes of the patient. With proper antigen selection and the determination of secretor status, these anti-blood group MoAb may be of clinical utility in the diagnosis of pancreatic cancer.

Establishment of an enzyme immunoassay using monoclonal antibody (HG1-219) and its application for the diagnosis of hepatocellular carcinoma

A monoclonal antibody (MoAb HG1-219) against a human gastric cancer cell line (HuG-1) and its shedding antigen (HG1-219 Ag) was generated and a solid-phase sandwich enzyme immunoassay (EIA-219) was developed. The mean serum HG1-219 Ag concentration in normal individuals was 30.5 +/- 14.5 U/ml measured by EIA-219. When the mean +3 SD of the antigen concentration in normal individuals was used as a cut-off level, 4.3% (2/47) of patients with chronic hepatitis, 9.1% (4/44) of cirrhotic patients and 37.5% (18/48) of patients with hepatocellular carcinoma (HCC) had HG1-219 Ag above the cut-off value. The positive rates of a-fetoprotein (AFP) (> 400 ng/ml) and protein induced by vitamin K absence or antagonist-II (PIVKA-II) for HCC were 26.7% (12/45) and 33.3% (12/36), respectively. There was no significant correlation between HG1-219 Ag and AFP or PIVKA-II in patients with HCC. The combination assay of EIA-219, AFP and PIVKA-II for HCC gave the positive rate of 75% (27/36). The effect of periodic acid on the HG1-219 Ag and the inhibition of EIA-219 by CA 19-9 suggest that the epitope of HG1-219 Ag is a suger chain similar to CA 19-9.

Comparison of the biodistribution of 75Se- and 131I-labelled monoclonal antibodies in nude mice

A monoclonal antibody, C-215, against colon cancer, was internally labelled with [75Se]methionine. The biodistribution was studied in tumour-bearing nude mice and compared with the biodistribution of [131I]C-215. The tissue uptake was divided into three parts: antibody bound to the antigen, antibody in the extracellular space and uptake of the released radionuclide. [75Se]C-215 showed a greater amount of antigen-bound antibody in the tumour, but also a greater unspecific uptake both in tumour and normal tissue.

Expression of CA 50 in normal human skin: comparative study of CEA and CA 19-9

Normal skin specimens from different body sites were estimated for the expression of CA 50 in comparison with CA 19-9 and CEA. Expression of CA 50 and CA 19-9 was observed in the ductal system and a small part of the secretory portion of eccrine units, but never in any other skin components including apocrine units. CEA was expressed on the ductal and a small part of the secretory portion of apocrine units as well as on those of eccrine units. However, the expression pattern and intensity in eccrine units were different from those of CA 50 or CA 19-9. We concluded that CA 50 was strongly expressed in the normal ductal system of eccrine units and hence could be standardized to stain the eccrine ductal portion and that immunohistochemical comparative studies with CA 19-9 or CEA might be a good methodological technique for discriminating an eccrine or apocrine origin for some skin disorders.