Circulating DF3 and CA125 antigen levels in serum from patients with epithelial ovarian carcinoma

Tumour Associated Antigens CA 15.3 and CA 125 in Ovarian Cancer

CA 125 and CA 15.3 antigens were determined by enzyme immunoassay in 78 patients with ovarian cancer for a total of 540 determinations. The antigens were also investigated in sera from 100 women with other gynaecological diseases, 82 lung cancer patients and in 39 pleural fluids of varying origin. CA 15.3 reference values were evaluated in 91 healthy women (cut-off: 25 U/ml). CA 15.3 sensitivity at diagnosis (60%) and for detecting relapse (44%) was lower than that of CA 125 (90% and 64,7%, respectively). However, CA 15.3 does not increase with aspecific mesothelial cell reaction and thus it is more specific than CA 125. Combined use of the markers during follow-up improves early detection of relapse (at least one of the two was positive in 79%, of cases). Therefore both CA 15.3 and CA 125 should be routinely determined for the detection and monitoring of ovarian cancer.

Clinical Evaluation of a New Two-Site Assay for CA125 Antigen

As appropriate surgery and chemotherapy can improve both quality of life and survival of patients with ovarian adenocarcinoma, there has been a pressing need for “serodiagnostic” assays to enable close patient monitoring. CA 125 antigen has previously been described as a useful tumor marker of ovarian cancer. This is the first clinical evaluation of a radioimmunoassay using two new monoclonal antibodies, B27.1 and B43.13, that react with separate sites on the glycoprotein marker CA 125. Using the new assay, the majority of patients with clinically or radiologically detectable disease had serum CA 125 antigen levels well above the upper limit seen with random apparently healthy donors, while only three patients who were believed free of disease had elevated levels. Disease progression was associated with increasing values of serum CA 125 antigen, while response to therapy was associated with a steady decline in serum CA 125 antigen levels. Seven patients had steadily rising serum CA 125 antigen levels after initially having normal levels. The mean lead time between rise above normal and clinical or radiological evidence of relapse was 5 months (range 2 to 12 months). The merits of further surgical intervention are illustrated by the serial values of two patients followed after chemotherapy.

The assay appears to have value in monitoring response to therapy and in detecting disease relapse at a time when appropriate therapeutic intervention is still possible or likely to be beneficial. Furthermore, monitoring CA 125 antigen was shown to be of benefit in assessing response to chemotherapy in a few patients with metastatic adenocarcinoma of unknown primary, and may be useful in this group of patients in determining those likely to benefit from aggressive chemotherapy.

Targeted Immunotherapy Designed to Treat MUC1-Expressing Solid Tumour

Several approaches to antigen-specific immunotherapy of cancer antigen-specific immunotherapy of cancer have been tested clinically. In this chapter, we will describe studies done with the antigen MUC1. Tested MUC1 therapeutic vaccines include the following: monoclonal antibodies (MAbs) specific for MUC1; synthetic and recombinant polypeptides from the protein sequence of MUC1; dendritic cells carrying MUC1; RNA and DNA vaccinations; and recombinant viruses carrying the MUC1 DNA sequence. Chemotherapy of cancer aims to be toxic to the cancer cells with manageable side effects to the patient. In contrast, antigen-specific immunotherapy of cancer aims to treat the patient, such that the patient is then able to control and eventually eliminate their cancer cells. It is therefore important to know the immune status of each cancer patient prior to therapy.

Difference in mesothelin-binding ability of serum CA125 between patients with endometriosis and epithelial ovarian cancer

The epithelial ovarian carcinoma (EOC) is an aggressive malignant tumor, and is currently the leading cause of gynecologic cancer death. CA125 is the most commonly used serum marker for EOC, but shows a high-false-positive rate for several benign diseases such as endometriosis. The purpose of our study is therefore to identify a useful biochemical tool for detecting qualitative differences between CA125 from patients with endometriosis and EOC, and to facilitate differential diagnosis of these diseases. In our study, using two different CA125-binding molecules, i.e., recombinant mesothelin and an anti-CA125 monoclonal antibody, a novel sandwich ELISA for determining the serum levels of CA125 with mesothelin-binding ability (CA125(meso) ) was developed, and tested for patients with endometriosis (n = 59) and EOC (n = 36). We found that both the serum CA125(meso) level and the ratio of the serum CA125(meso) to CA125 levels (CA125(meso) /CA125) were significantly higher in patients with EOC than in patients with endometriosis (p < 0.00005 and p < 0.000001, respectively). Furthermore, receiver operating characteristic analysis showed that the CA125(meso) assay was superior to the conventional antibody-based CA125 assay in discriminating endometriosis from EOC. Thus, mesothelin-binding ability may be a useful indicator for qualitatively evaluating CA125 in patients with endometriosis and EOC.

Human prominin-1 (CD133) is detected in both neoplastic and non-neoplastic salivary gland diseases and released into saliva in a ubiquitinated form

Prominin-1 (CD133) is physiologically expressed at the apical membranes of secretory (serous and mucous) and duct cells of major salivary glands. We investigated its expression in various human salivary gland lesions using two distinct anti-prominin-1 monoclonal antibodies (80B258 and AC133) applied on paraffin-embedded sections and characterized its occurrence in saliva. The 80B258 epitope was extensively expressed in adenoid cystic carcinoma, in lesser extent in acinic cell carcinoma and pleomorphic adenoma, and rarely in mucoepidermoid carcinoma. The 80B258 immunoreactivity was predominately detected at the apical membrane of tumor cells showing acinar or intercalated duct cell differentiation, which lined duct- or cyst-like structures, and in luminal secretions. It was observed on the whole cell membrane in non-luminal structures present in the vicinity of thin-walled blood vessels and hemorrhagic areas in adenoid cystic carcinoma. Of note, AC133 labeled only a subset of 80B258–positive structures. In peritumoral salivary gland tissues as well as in obstructive sialadenitis, an up-regulation of prominin-1 (both 80B258 and AC133 immunoreactivities) was observed in intercalated duct cells. In most tissues, prominin-1 was partially co-expressed with two cancer markers: carcinoembryonic antigen (CEA) and mucin-1 (MUC1). Differential centrifugation of saliva followed by immunoblotting indicated that all three markers were released in association with small membrane vesicles. Immuno-isolated prominin-1–positive vesicles contained CEA and MUC1, but also exosome-related proteins CD63, flotillin-1, flotillin-2 and the adaptor protein syntenin-1. The latter protein was shown to interact with prominin-1 as demonstrated by its co-immunoisolation. A fraction of saliva-associated prominin-1 appeared to be ubiquitinated. Collectively, our findings bring new insights into the biochemistry and trafficking of prominin-1 as well as its immunohistochemical profile in certain types of salivary gland tumors and inflammatory diseases.

Different levels of sialyl-Tn antigen expressed on MUC16 in patients with endometriosis and ovarian cancer

OBJECTIVE

Although CA125 antigen is a useful marker for ovarian cancer, its expression is also elevated in endometriosis. The purpose of this study was to develop an assay method for evaluating differentially glycosylated MUC16 (CA125 core protein) in patients with endometriosis and ovarian cancer.

MATERIALS AND METHODS

We prepared MUC16-enriched fractions from peritoneal fluid of patients with endometriosis and conditioned medium of ovarian carcinoma-3 cells by gel filtration, and evaluated the expression of sialyl-Le, Tn, and sialyl-Tn antigens by dot blot analysis. A sandwich enzyme-linked immunosorbent assay was developed to measure the level of sialyl-Tn antigen expressed on MUC16 (sTn/MUC16). The level of sTn/MUC16 was compared between patients with endometriosis (n = 21) and ovarian cancer (n = 36) and in ovarian cancers with different clinical diagnostic criteria. Furthermore, distribution of MUC16 and sialyl-Tn antigen in ovarian cancer tissues was observed immunohistochemically.

RESULTS

Sialyl-Tn antigen was markedly detectable in the MUC16-enriched fractions from conditioned medium of ovarian carcinoma-3 cells but negligible in those from the peritoneal fluid of the patients with endometriosis. The level of sTn/MUC16 determined by a sandwich enzyme-linked immunosorbent assay was significantly higher in the patients with ovarian cancer than that in the patients with endometriosis (P < 0.001). An elevated level of sTn/MUC16 was detected in 44% of the patients with ovarian cancer but not all the patients with endometriosis. This level increased more prominently in the patients with ovarian cancer than that of MUC16 as both the clinical stage and cytological grade advanced. An elevated level of sTn/MUC16 was frequently found in the patients with serous and endometrioid carcinomas. Consistent with this, sialyl-Tn antigen was colocalized with MUC16 in serous and endometrioid ovarian cancer tissues.

CONCLUSIONS

Estimation of the sTn/MUC16 level may be useful for discriminating endometriosis from ovarian cancer and for evaluating the clinical stage, cytological grade, and histological type of ovarian cancer.

Progress in ovarian cancer research: Proceedings of the 5th Biennial Ovarian Cancer Research Symposium

Ovarian cancer remains the most lethal gynecological malignancy. The 5th Biennial Symposium overviewed the progress of ovarian cancer research over the last few years. Molecularly based technologies have allowed the identification of multiple biomarkers to aid in ovarian cancer diagnosis and treatment. Furthermore, data analysis systems evaluating the behavior of these markers have been designed. Therapeutic use of ovarian cancer protein markers has been fueled by the development of animal models that more closely simulate the pathogenesis of ovarian cancer, and multiple new therapies are being developed that may have impact against the disease. Finally, the design of clinical trials both for ovarian cancer treatment and prevention are key in advancing the science of ovarian cancer into the clinic. The need for strategies that would optimize patient participation in clinical trials is paramount.

Potential markers that complement expression of CA125 in epithelial ovarian cancer

BACKGROUND

When ovarian carcinoma is diagnosed in stage I, up to 90% of patients can be cured with surgery and currently available chemotherapy. At present, less than 25% of cases are diagnosed at this stage. To increase the fraction of ovarian cancers detected at an early stage, screening strategies have been devised that utilize a rising serum CA125 level to trigger the performance of transvaginal sonography. One limitation of CA125 as an initial step in such a screening strategy is that up to 20% of ovarian cancers lack expression of the antigen. Serum tumor markers that can be detected in ovarian cancers that lack CA125 expression might improve the sensitivity for early detection.

METHODS

From 296 ovarian cancers, 65 (22%) were found to have weak or absent CA125 expression on immunoperoxidase staining. Tissue expression of CA125 was compared to serum CA125 levels. Using immunoperoxidase staining of tissue arrays, we have assessed expression of 10 potential serum tumor markers in the 65 epithelial ovarian cancers with little or no CA125 expression and in ovarian cystadenomas, tumors of low malignant potential, normal ovaries, and 16 other normal tissues.

RESULTS

Low or absent expression of CA125 in surgical specimens of epithelial ovarian cancer was associated with low levels of serum CA125 in pre-operative serum specimens. In ovarian cancers that lacked CA125, all specimens (100%) expressed human kallikrein 10 (HK10), human kallikrein 6 (HK6), osteopontin (OPN), and claudin 3. A smaller fraction of CA125-deficient ovarian cancers expressed DF3 (95%), vascular endothelial growth factor (VEGF) (81%), MUC1 (62%), mesothelin (MES) (34%), HE4 (32%), and CA19-9 (29%). When reactivity with normal tissues was considered, however, MES and HE4 showed the greatest specificity. Differential expression was also found for HK10, OPN, DF3, and MUC1.

CONCLUSIONS

At the level of tissue expression, each of 10 potential serum markers could be detected in 29-100% of ovarian cancers that had low or absent expression of CA125. Several markers exhibited more intense expression in cancers than in normal organs. Further investigation is needed to demonstrate complementary expression of markers in serum.

Recovery of CD8+ T-Cell Function During Systemic Chemotherapy in Advanced Ovarian Cancer

Immunologic approaches are emerging as new treatment options in several types of cancer. However, whereas the ability of patients to develop potent CD8+ T-cell responses is crucial for efficient antitumor responses, immunocompetence and T-cell function are not tested routinely in patients entering immunotherapy. The objective of our study was to monitor T-cell function in advanced cancer and during chemotherapy. CD8+ T-cell function of 21 patients with advanced ovarian cancer (stages III-IV) was assessed by cytokine flow cytometry following stimulation of 42 PBMC samples with a panel of synthetic viral peptides in vitro, consisting of pan-Caucasian epitopes. CD8+ T-cell responses were significantly lower in patients with high levels (>200 units/mL) of Ca125 (marker of tumor load and progression) than in those with low Ca125 levels (P = 0.0013). In longitudinal studies of nine patients, chemotherapy was associated with decreasing Ca125 levels in seven cases and also with improvement or maintenance of CD8+ T-cell function in seven cases. After the full course of chemotherapy, five of nine patients in remission displayed potent CD8+ T-cell responses, whereas four of nine patients in progression displayed low or decreasing T-cell responses, pointing toward a correlation between T-cell function and clinical response. Our results show for the first time that CD8+ T-cell function is not permanently suppressed in advanced cancer and successful chemotherapy is associated with improved antigen-specific T-cell reactivity. We suggest that functional assays determining T-cell immunocompetence can be valuable tools for optimizing cancer immunotherapy for improved clinical success.

Selection and characterization of MUC1-specific CD8+ T cells from MUC1 transgenic mice immunized with dendritic-carcinoma fusion cells

Mice transgenic for the human MUC1 carcinoma-associated antigen (MUC1.Tg) are tolerant to immunization with MUC1 antigen. Recent studies, however, have demonstrated that immunization of MUC1.Tg mice with fusions of MUC1-positive tumour and dendritic cells (FC/MUC1) reverses MUC1 unresponsiveness and results in rejection of established MUC1-positive pulmonary metastases. Here we demonstrate that lymph node cells from MUC1.Tg mice immunized with the FC/MUC1 fusion cells proliferate in response to MUC1 antigen by a mechanism dependent on the function of CD4, major histocompatibility complex (MHC) class II, B7-1, B7-2, CD28, CD40 and CD40 ligand. The findings demonstrate that stimulation of lymph node cells with MUC1 results in selection of MUC1-specific CD8+ T cells. We show that the CD8+ T cells exhibit MUC1-specific cytotoxic T lymphocyte (CTL) activity by recognition of MUC1 peptides presented in the context of MHC class I molecules Kb and Db. The MUC1-specific CD8+ T cells also exhibit antitumour activity against MUC1-positive metastases, but with no apparent reactivity against normal tissues. These results indicate that immunization of MUC1.Tg mice with FC/MUC1 reverses immunological unresponsiveness to MUC1 by presentation of MUC1 peptides in the presence of costimulatory signals and generates MHC-restricted MUC1-specific CD8+ T cells.

Serum (circulating) tumor markers for breast cancer

Many circulating markers have been proposed for breast cancer, with potential utility for identification, screening, prognosis, detection, or monitoring. Of the available markers, those with the greatest promise include circulating tumor markers that provide an indication of clinical course, such as CA15-3 and CEA, and novel markers such as BrCa1, antibodies to p53, antibodies to HER-2/neu, indicators of angiogenesis, and the extracellular domain of HER-2/neu. However, the precise clinical utilities of all of these markers have yet to be determined. It is especially important that the relative independence of the markers in relation to other available markers be determined so as to avoid the unnecessary cost and expense of redundancy. Moreover, it is important that the clinician be aware of the limitations in both sensitivity and specificity of each marker so as not to over- or under-interpret the predictive value of any test.

The epidemiology of ovarian carcinoma and the current status of tumor markers to detect disease

OBJECTIVES

The objectives of this manuscript are to review the epidemiologic characteristics of ovarian cancer and to summarize the current status of tumor markers to detect disease.

STUDY DESIGN

A review of the pertinent literature was done.

RESULTS

In general, ovarian cancer is most frequent in industrialized countries, with dietary fat and possible use of talc as additive factors. Ovulation appears to increase the risk as does family history, increasing age, infertility, and possibly the use of ovulatory drugs. Pregnancy and the use of oral contraceptives, as well as possibly breast-feeding, lower the risk. Tubal ligation or hysterectomy with ovarian preservation also lowers the risk. The lifetime risk is about 1.4% in the United States, and the risk increases with age. If one first-degree relative has ovarian cancer, the lifetime risk appears to rise to 5%, but this pooled estimate may be affected by self-reporting bias in some studies. CA 125, the most widely used marker, is nonspecific, being elevated in about 80% of cases of ovarian epithelial cancer but also elevated in a number of benign conditions, which reduces its potential effectiveness as a screening tool.

CONCLUSIONS

No single cause of ovarian cancer has been uncovered. Overall > 90% of ovarian cancers occur sporadically. Those with the hereditary ovarian cancer syndrome (multiple generations of breast and ovarian cancer) have a 50% risk and an autosomal dominant inheritance, but they constitute < 1% of cases. No ideal tumor marker for ovarian cancer screening is currently available. Further evaluation is needed to see whether the use of multiple tumor markers and/or vaginal ultrasonography might produce an acceptable cost-effective screening model. Current data do not support the utilization of prophylactic oophorectomy in women with one first-degree relative with ovarian cancer as a general strategy to prevent ovarian cancer. It is appropriate strategy for those with hereditary ovarian cancer syndrome.

Tumor markers for breast cancer

Many antigenic and genetic markers have been proposed for breast cancer, with potential utility in identification, screening, prognosis, detection, or monitoring. Of the available markers, those with the greatest promise in 1993 include the yet-to-be-cloned BrCa1, the p53 tumor suppressor gene, tissue-associated prognostic factors such as HER-2/neu, cathepsin-D, and indicators of angiogenesis, and circulating tumor markers that provide an indication of clinical course, such as CA15-3 and CEA. However, the precise clinical utilities of all of these markers have yet to be determined. It is especially important that the relative independence of the markers in relation to other available markers to determined so as to avoid the unnecessary cost and expense of redundancy. Moreover, it is important that the clinician be aware of the limitations in both sensitivity and specificity of each marker so as not to sensitivity and specificity of each marker so as not to over- or under-interpret the predictive value of any test. With these caveats in mind, judicial application of germ-line, tissue, and soluble tumor markers can improve clinical care of patients at risk for and with breast cancer.

The management of ovarian carcinoma is improved by the use of cancer-associated serum antigen and CA 125 assays

BACKGROUND

The new tumor-associated mucin assay, cancer-associated serum antigen (CASA), was assessed with the CA 125 assay for use in the management of patients with epithelial ovarian cancer.

METHODS

CASA and CA 125 were assessed retrospectively for use in (1) monitoring 28 patients with Stage 3 or 4 ovarian carcinoma during therapy, (2) predicting the outcome of 41 second-look laparotomies (SLL), and (3) predicting the survival outcome by measuring these levels after surgery but before chemotherapy in 65 patients with Stage 3 disease.

RESULTS

Of 20 patients with recurrence after an initial response, the presence of CASA levels detected recurrence in 65% before clinical detection; CA 125, 50%; and the combination of CASA and CA 125, 80%. Six patients whose disease was in long-term remission did not have elevations of either marker. When used to predict the results of SLL, the positive predictive values of CASA and CA 125 were 77% and 100%, respectively. The negative predictive values for CASA and CA 125 were 71% and 66%, respectively. CASA detected 50% of positive SLL where microscopic disease only was found; the CA 125 test did not. Multivariate analysis of survival rates using levels of CASA and CA 125, age, residual disease, tumor type and grade, or the presence or absence of cisplatin in the chemotherapeutic regimen found that postoperative CASA levels ranked above all prognostic factors except age. CASA levels may be more accurate than surgical reporting of residual disease or they may define a subset of patients with biologically more aggressive ovarian carcinoma.

CONCLUSIONS

The CASA test is sensitive to ovarian carcinoma, and both CASA and CA 125 are more useful when used in conjunction.

Coordinate elevation of serum markers in ovarian cancer but not in benign disease

Effective screening for occult ovarian cancer will require a strategy that is both sensitive and specific. Preliminary data suggest that CA 125 is elevated at diagnosis in a majority of patients with ovarian cancer. Although CA 125 is sufficiently specific to prompt its evaluation as one component of a strategy to detect ovarian cancer in postmenopausal women, a further improvement in specificity would facilitate cost-effective screening. In an attempt to develop a more specific screening strategy, multiple markers were assayed in a panel of sera from 47 patients with ovarian cancer and in a separate panel of sera from 50 individuals with benign disease whose serum CA 125 levels exceeded 35 U/ml. Among the patients with ovarian cancer, elevations of CA 125 (greater than 35 U/ml) were observed in 91%, CA 15-3 (greater than 30 U/ml) in 57%, TAG 72 (greater than 10 U/ml) in 49%, placental alkaline phosphatase (PLAP) in 25%, human milk fat globule protein (HMFG) 1 in 77%, HMFG2 in 62%, and NB/70K in 57%. Among the 50 sera selected from patients with benign disease, CA 125 was more than 35 U/ml in 100% and more than 65 U/ml in 42%. Among those patients with benign disease and elevated CA 125, NB/70K was elevated in 62%, HMFG1 in 26%, and HMFG2 in 12%, whereas TAG 72 and CA 15-3 were elevated in only 6% and 2%, respectively. In addition PLAP appeared promising; elevated enzyme levels were not found in the benign disease group. Among patients with ovarian cancer with CA 125 levels more than 35 U/ml, either TAG 72 or CA 15-3 was elevated in 77%. In the false-positive group, only 6% had elevations of one or the other marker. The CA 125 levels in cancer patients were, however, substantially greater than in patients with benign disease. If sera from patients with ovarian cancer were diluted to a range comparable to that found in benign disease, at least one of the two confirmatory tests was elevated in 63% of the samples from the malignant cases. Consequently, use of CA 15-3 and TAG 72 in combination with CA 125 can increase the apparent specificity of the CA 125 assay for distinguishing malignant from benign disease. Prospective studies will be required to test critically whether the use of additional serum markers in combination with the CA 125 assay would contribute to the specificity of a cost-effective screening strategy for ovarian cancer.

Multiple epitopes of the human ovarian cancer antigen 14C1 recognised by human IgG antibodies: their potential in immunotherapy

We have defined a novel ovarian cancer-associated membrane antigen, 14C1, using human monoclonal antibodies derived by EBV-transformation of in situ sensitised patients' B-cells. The pattern of recognition of this antigen by these antibodies suggests that at least three epitopes are discernable. These antibodies can be used to promote the in vitro killing of ovarian cancer cells by activated macrophages and cytokines, implying a role for this antigen in the immunotherapy of ovarian malignancies. Evidence is presented that the 14C1 antigen may have some transmembrane signalling function.

14C1, an antigen associated with human ovarian cancer, defined using a human IgG monoclonal antibody

We have selected a human EBV-transformed cell line from the involved lymph nodes of an ovarian cancer patient which secretes an IgG1 kappa antibody, able to recognize an antigen present on the surface of ovarian cancer cells. The antigen, termed '14Cl,' has previously been shown by immunohistological techniques to be present on the surface of the malignant cells within tumour specimens. Western blotting analysis has shown that the majority of primary ovarian cancer specimens and three continuous cell lines derived therefrom express 14Cl; other tissue types were negative. Preliminary biochemical characterization has been carried out, which shows that the 14Cl antigen has a molecular weight range of 25-32 kD and an isoelectric point from pI 6.3 to 6.8. We believe that the 14Cl antigen is immunologically relevant to ovarian cancer patients and may therefore represent a novel target for both active and passive immunotherapy.

Preoperative evaluation of serum CA 125, TAG 72, and CA 15-3 in patients with endometrial carcinoma

We evaluated 109 women with endometrial carcinoma to determine the accuracy of preoperative tumor-associated antigen levels (CA 125, CA 72, CA 15-3) for prediction of extrauterine disease and whether TAG 72, CA 15-3, or both would improve the predictive value of CA 125 alone. Eleven (12%) of 80 patients with disease confined to the uterus or positive cytologic findings had CA 125 values greater than 35 U/ml versus 12 (65%) of 20 patients with extrauterine metastasis. Therefore CA 125 values had sensitivity of 65% and specificity of 88%. The TAG 72 level was elevated (greater than 6 U/ml) in 4% of patients with localized disease and 30% with metastasis. CA 15-3 was elevated (greater than 30 U/ml) in 17% and 65% in these categories, respectively. TAG 72 or CA 15-3 levels did not improve the combination of sensitivity and specificity of CA 125 alone. In addition, only one of 10 patients with microscopic metastasis (three cases) or positive peritoneal cytology (seven) had elevation of any of these tumor-associated antigen levels. Failure to detect occult metastasis and a high false-positive rate limit the role of these tumor-associated antigen assays in the preoperative evaluation of patients with endometrial carcinoma.

Evaluation of two new assays for tumor-associated antigens, CASA and OSA, found in the serum of patients with epithelial ovarian carcinoma--comparison with CA125

Two new assays have been developed to measure tumor-associated antigens designated ovarian serum antigen (OSA) and cancer-associated serum antigen (CASA). Both assays are dual epitope ELISAs using the same capture monoclonal antibody (BC2); the second antibodies in the OSA and CASA assays are OM-1 and BC3, respectively. Using arbitrary cutoffs of 2.5 and 3.0 units/ml, 82 and 76% of 80 serum samples from ovarian cancer patients were positive for OSA and CASA, respectively, compared with 5 and 2.5% of samples from a control population of 40 women. A strong correlation was found between the two assays (r = 0.80, P less than 0.001). CA125 levels were obtained from 49 of the 80 samples; 82% of these samples were positive for CA125 (greater than 35 U/ml), 82% for OSA and 73% for CASA. Of the 9 samples negative for CA125, 3 were positive for OSA and 3 were positive for CASA. Serum OSA, CASA, and CA125 levels were determined in serial samples from 20 ovarian carcinoma patients throughout the course of their treatment. Clinical course was accurately reflected by CA125 levels in 85% of patients, by CASA in 65%, and by OSA in 75%. In 4 patients, a rise in CASA levels and, in 2 patients, a rise in OSA levels significantly predated rising CA125 levels to predict recurrence. Six of 7 serum samples obtained prior to positive second-look laparotomy were negative for CA125, while 4 were positive for OSA and 6 were positive for CASA. These results indicate that the OSA and CASA assays could be superior to CA125 for detection of small volume occult ovarian carcinoma.

Expression of multiple tumour markers in serum from patients with ovarian carcinoma and healthy women

Serum samples from 70 patients with bulky ovarian carcinomas, 46 patients with surgically extirpated Stage I ovarian carcinomas, and 108 aged-matched healthy control subjects were assayed for 10 tumour-associated antigens. Levels of expression of each antigen were progressively increased in treated Stage I and bulky disease patients over healthy controls. Levels of expression in treated Stage I patients inversely reflected the interval between surgery and collection of the sample. For patients with bulky disease, determination of correlation coefficients of expression of each antigen against each other antigen showed that in 9 of 45 such relationships, the coefficients were greater than 0.30, suggesting significant coexpression. The best correlation was found for CA125 and MSA, HMFG2 and MSA, DCA and MSA, and DCA and HMFG2. By multivariate discriminant function analysis, the combination of 2 assays (CA125 and NB/70K) was found to increase specificity of detection of ovarian carcinoma over one assay alone (CA125). Use of more than these 2 assays increased sensitivity only marginally. The attained specificity is insufficient for use as a screening assay for ovarian cancer alone, given the low prevalence in the community of this disease.

Circulating CA 15-3 antigen levels in non-mammary malignancies

Abnormal CA 15-3 antigen levels are found in the serum of most patients with advanced breast carcinoma. Elevations of this marker are less frequently seen in other malignancies. Circulating CA 15-3 levels might be useful in the differential diagnosis of the primary site of cancer. We studied the levels of CA 15-3 in 500 patients with different non-mammary cancers. Elevations of CA 15-3 (greater than 40 U ml-1) were observed in all types of epithelial malignancies, especially in ovarian (46%), respiratory (26%) and liver (30%) carcinomas. Abnormal values were observed in some patients with haematological malignancies and sarcomas, but not in melanoma or neurological tumours. CA 15-3 antigen levels correlated with the extent of non-mammary malignant tumours. Patients with locoregional cancer had a significantly smaller proportion of elevations of the antigen than those with distant metastases (12% versus 35%, P less than 0.001). In particular, elevated CA 15-3 levels were observed in 70% of patients with metastatic ovarian cancer. Liver involvement by cancer did not produce more elevations of CA 15-3 than metastases to other organs (32% versus 39%). Simultaneous determination of circulating CA 15-3 and CA 125 antigens in 58 patients with cancer of the ovary showed that CA 15-3 is elevated in some cases of ovarian carcinoma with non-elevated CA 125, and that CA 15-3 and CA 125 are distinct antigens. We conclude that circulating CA 15-3 antigen levels can be found elevated in virtually all types of cancer, particularly when distant metastases are present. Therefore, CA 15-3 levels should not be used in the differential diagnosis of the primary site in patients with metastatic malignancies of unknown origin. Evaluation of CA 15-3 levels may enhance the sensitivity of CA 125 in monitoring the course of ovarian carcinoma.

Double antibody radioimmunoassay for monitoring metastatic breast cancer

We previously reported the production of a panel of murine monoclonal antibodies which recognize glycoproteins abnormally expressed in human breast tumours. Using two of these antibodies, a double antibody radioimmunoassay was designed to quantify levels of these breast tumour marker glycoproteins in serum. Marker levels greater than 28 units were considered abnormal. Using this criterion, 63% and 75% of patients with breast cancer stages I and II, respectively, and 88% of those with metastatic disease were found to have elevated marker levels. Thirteen percent of patients with non-malignant breast disease also had elevated marker levels. Elevated marker levels were also detected in patients with non breast neoplasms. One hundred and eleven women with metastatic disease were followed. Eighty-two percent of those with progressive disease and 73% of those where disease regressed had 20% changes in marker levels. These changes in marker levels preceded by up to 6 months changes in disease state. From these results we conclude that this assay may be useful for monitoring the course of disease in breast cancer patients.

Preoperative evaluation of serum CA 125 levels in premenopausal and postmenopausal patients with pelvic masses: discrimination of benign from malignant disease

CA 125 levels were measured in 158 patients with palpable pelvic masses who were about to undergo diagnostic laparotomy. When the 68 patients found to have cancer were compared with the 90 patients with benign disease, those with malignancies were significantly older, were more frequently postmenopausal, and had significantly higher values of serum CA 125. Patients with benign pelvic masses had CA 125 levels greater than 65 U/ml in 8% of cases, whereas those with malignancies had CA 125 levels greater than 65 U/ml in 75% of cases. If only those patients who had frankly malignant, primary, nonmucinous epithelial ovarian carcinomas were considered, CA 125 levels greater than 65 U/ml predicted malignancy with a sensitivity of 91% for all patients. Greater sensitivity and specificity were observed in the postmenopausal subgroup than in the premenopausal subgroup. In the postmenopausal group with a 63% prevalence of ovarian cancer the predictive positive value was 98% and the predictive value negative was 72%. In a premenopausal population with a 15% prevalence of ovarian cancer the predictive value for a positive test was 49%, while the predictive value for a negative test was 93%.

Isolation and sequencing of a cDNA coding for the human DF3 breast carcinoma-associated antigen

The murine monoclonal antibody (mAb) DF3 reacts with a high molecular weight glycoprotein detectable in human breast carcinomas. DF3 antigen expression correlates with human breast tumor differentiation, and the detection of a cross-reactive species in human milk has suggested that this antigen might be useful as a marker of differentiated mammary epithelium. To further characterize DF3 antigen expression, we have isolated a cDNA clone from a lambda gt11 library by screening with mAb DF3. The results demonstrate that this 309-base-pair cDNA, designated pDF9.3, codes for the DF3 epitope. Southern blot analyses of EcoRI-digested DNAs from six human tumor cell lines with 32P-labeled pDF9.3 have revealed a restriction fragment length polymorphism. Variations in size of the alleles detected by pDF9.3 were also identified in Pst I, but not in HindIII, DNA digests. Furthermore, hybridization of 32P-labeled pDF9.3 with total cellular RNA from each of these cell lines demonstrated either one or two transcripts that varied from 4.1 to 7.1 kilobases in size. The presence of differently sized transcripts detected by pDF9.3 was also found to correspond with the polymorphic expression of DF3 glycoproteins. Nucleotide sequence analysis of pDF9.3 has revealed a highly conserved (G + C)-rich 60-base-pair tandem repeat. These findings suggest that the variation in size of alleles coding for the polymorphic DF3 glycoprotein may represent different numbers of repeats.

Pre-operative discrimination between benign and malignant ovarian tumors using a combination of CA125 and CA15.3 serum assays

Serum levels of CA125 and CA15.3 were measured in 70 patients presenting with an ovarian neoplasm, of whom 38 had an ovarian malignancy and 32 a benign ovarian tumor. CA125 levels exceeded 35 U/ml in 71% of ovarian carcinomas and in 25% of benign ovarian tumors. In the entire group of 70 patients, CA125 levels (greater than 35 U/ml) were elevated in 35 patients, of whom 27 had ovarian cancer. CA15.3 levels were found to be elevated (greater than 30 U/ml) in 9% of benign ovarian tumors and in 50% of ovarian malignancies. Of 8 patients with a false positive CA125 (greater than 35) elevation, only one had an elevated CA15.3 level whereas in 27 correct positive patients 19 also had elevated CA15.3 levels. Of all 20 patients with both markers elevated, 19 patients (95%) had ovarian cancer. When a cut-off level of 65 U/ml was used for the tumor marker CA125, all patients with simultaneous elevation of both markers were found to have an ovarian malignancy. Using a panel of CA125 (greater than 35 U/ml) and CA15.3 (greater than 30 U/ml) and requiring a simultaneous marker elevation, the sensitivity of the test decreased from 71% to 50% but the corresponding specificity of the test rose from 75% to 97%. Specificity was as high as 100% if in the same panel of tests a 65 U/ml cut-off for CA125 was taken. A comparison of early stage I-II ovarian cancer with benign ovarian tumors failed to demonstrate a discriminatory capacity of any test or test combination. We conclude that the use of a panel of tumor markers is advantageous in the pre-operative discrimination of benign and malignant ovarian tumors, since the predictive value for malignancy of a combined marker elevation was as high as 100% in the population studied.

Elevated serum HMFG antigen levels in breast and ovarian cancer patients measured with a sandwich ELISA

HMFG antigen is a tumour associated glycoprotein that has been immunohistochemically shown to be expressed by malignant cells in breast and ovarian and to a lesser degree in gastro-intestinal carcinomas. We have developed a non-isotopic sandwich ELISA for secretory HMFG antigen utilizing a polyclonal catcher and a tracer monoclonal antibody (MAb). 52/52 of healthy medical students (controls) had a serum value under 400 U/ml whereas 15/30 patients (50%) with evident ovarian cancer and 13/37 (35%) with advanced breast cancer had a value exceeding 400 U/ml. From other patients with malignant tumours 2/14 (14%) with endometrial carcinoma, 0/5 with cervical carcinoma, 0/5 with vulvar carcinoma, 1/33 with gastro-intestinal carcinoma, 0/4 with oesophageal carcinoma and 2/45 of patients with leukemia or lymphoma had an elevated serum HMFG value. Four cases of Crohn disease, 3 cases of ulcerative colitis and 2 cases of pelvic inflammatory disease all showed a serum value below 400 U/ml. Progression of ovarian cancer was accompanied by increasing serum HMFG antigen levels. The antigen detected by our assay is different from CA 125 but may be related with the tumour associated antigen CA 15-3.

Prognostic factors in borderline and invasive ovarian tumors of the common epithelial type

Present reports show that surgical factors, response to therapy and histological criteria are important for predicting the prognosis of patients with common epithelial types of ovarian tumors. Newer techniques such as morphometry, DNA cytometry, immunological and immunopathological techniques may help to define prognostic factors even more accurately. As a result, these recently developed methods may enhance the value of well-established classical predictors of the outcome in case of borderline or invasive ovarian tumour.

Pros and cons of gynecologic tumor markers

The use of a tumor marker not only depends upon its sensitivity and specificity, but also upon its ability to influence decisions between alternative plans for patient management. Use of beta human chorionic gonadotropin (hCG) for monitoring gestational trophoblastic neoplasia has set the standard to which other assays must be compared. Beta hCG and alphafetoprotein have provided useful markers for ovarian germ cell tumors. Recently, a monoclonal antibody-based immunoassay for CA 125 antigen has been used to monitor the treatment of epithelial ovarian carcinomas. Persistent elevation of CA 125 in serum has generally reflected persistence of disease at second look surveillance procedures. CA 125 levels can, however, return to within normal limits and residual disease can be found at laparoscopy or laparotomy. CA 125 shows promise for distinguishing benign from malignant pelvic masses. Trials are currently underway to evaluate the potential of CA 125 in combination with other markers to facilitate earlier detection of occult ovarian cancer.

Independent expression in serum of three tumour-associated antigens: CA 125, placental alkaline phosphatase and HMFG2 in ovarian carcinoma

Circulating levels of CA 125, the HMFG2 antigen and placental alkaline phosphatase were measured in patients with epithelial ovarian cancer. In 37 patients the antigens were assayed before operation and 161 follow-up samples from 41 patients were assayed at different times during treatment. These three human tumour-associated antigens were expressed independently of each other. Measurement of all three antigens, compared with measurement of CA 125 alone, resulted in a statistically significant improvement in the detection rate of patients with localized disease from 18% to 69%.

Circulating tumor-associated antigen detected by the monoclonal antibody HMFG2 in human epithelial ovarian cancer

A radioimmunometric sandwich assay for the tumour-associated antigen defined by the monoclonal antibody (MAb) HMFG2, has been used to measure serum levels of the antigen in 76 healthy controls, 38 ovarian carcinoma patients pre-operatively, 98 patients 2 to 6 weeks after surgery and 36 patients at relapse or in complete remission at 12 months. HMFG2 antigen levels were elevated in 33% of stage-I and 62% of II-IV patients pre-operatively; they reflected bulk of disease post-surgically and were significantly higher in patients in relapse than in those who were in complete remission. HMFG2 antigen levels predicted the clinical course of disease in the majority of patients.