A new immunoassay using monoclonal antibodies HMFG1 and HMFG2 together with an existing marker CA125 for the serological detection and management of epithelial ovarian cancer

Use of a deoxynojirimycin-fluorophore conjugate as a cell-specific imaging probe targeting α-glucosidase on cell membranes

Molecules designed for cell-specific imaging were studied, taking advantage of an enzyme-inhibitor interaction. 1-Deoxynojirimycin (DNJ) can be actively captured by cells which express the surface membrane protein α-glucosidase. New probes composed of DNJ for recognition linked to a fluorophore signal portion were prepared (DNJ-CF₃1, DNJ-Dans 2 and DNJ-DEAC 3). Docking simulations revealed that the inhibitors acarbose and miglitol and the inhibitor portion of the probes bind at the same position in the pocket of α-glucosidase (human-derived PDB: 3TON). The ability of probes 1-3 to detect the difference between HeLa cells (from human cervical cancer tissue), Neuro-2a cells (from a mouse neuroblastoma C1300 tumor), N1E-115 cells (from a mouse brain neuroblastoma C1300 tumor), A1 cells (from the astrocyte of a newborn mouse brain), and Caco-2 cells (from a human colon carcinoma) was evaluated, and cell-specific fluorescence imaging was possible for conjugate probes 1 and 2. Caco-2 cells treated with probes 1 and 2 showed blue and green fluorescence, respectively, from the cell membrane, and did not stain the Caco-2 cells inside. These results show that DNJ-CF₃1 and DNJ-Dans 2 recognize an α-glucosidase protein on the surface of Caco-2 cells. Probes 1 and 2 did not stain any part of the other cells. This cell-specific imaging strategy is applicable for a variety of therapeutic agents for many diseases.

CA125 in ovarian cancer: European Group on Tumor Markers guidelines for clinical use

CA125 is currently the most widely used tumor marker for ovarian epithelial cancer. The aim of this article is to provide guidelines for the routine clinical use of CA125 in patients with ovarian cancer. Due to lack of sensitivity for stage I disease and lack of specificity, CA125 is of little value in the detection of early ovarian cancer. At present, therefore, CA125, either alone or in combination with other modalities, cannot be recommended for screening for ovarian cancer in asymptomatic women outside the context of a randomized controlled trial. Preoperative levels in postmenopausal women, however, may aid the differentiation of benign and malignant pelvic masses. Serial levels during chemotherapy for ovarian cancer are useful for assessing response to treatment. Although serial monitoring following initial chemotherapy can lead to the early detection of recurrent disease, the clinical value of this lead-time is unclear. CA125 is the ovarian cancer marker against which new markers for this malignancy should be judged.

Circulating tumour-associated mucin concentrations, determined by the CASA assay, in healthy women

This investigation was undertaken to establish a reference range for tumour-associated MUC1 mucins in the serum of healthy women of the ages at risk for adenocarcinoma of the ovary and breast. Blood samples and clinical information were obtained from 5,000 women attending a breast screening mammography clinic. Data from women diagnosed with breast carcinoma and those subsequently diagnosed with other cancers were omitted from the reference range. Mucin concentrations were measured using the CASA assay which detects the protein core of MUC1 encoded mucins. Multiple linear regression analysis showed no effect on CASA concentrations by non-malignant changes to the breast, menopausal status, presence/absence of the reproductive tract, parity or history of hormone use. However, CASA concentrations were significantly increased in smokers (P < 0.001) and progressively increased with age (P < 0.001). These data show that these factors must be given consideration when setting upper limits of normal using MUC1 protein core binding assays.

Effects of interferon gamma on the proliferation and modulation of cell-surface structures of human ovarian carcinoma cell lines

Platinum-containing regimens are very effective in the primary treatment of ovarian cancer. However, upon subsequent treatment most tumors develop multidrug resistance. The clinical application of biological response modifiers like interferon gamma (IFN gamma) in advanced ovarian cancer is therefore of increasing interest. Permanent ovarian cancer cell lines are suitable for investigating the mode of action and the potential clinical effectiveness of such response modifiers. IFN gamma is known to modulate many cellular functions. In this study it was compared for its antiproliferative and antigen-modulatory activity on the expression of tumor-associated (CA-125, HMFG, CEA) and major histocompatibility complex (MHC) class I and II antigens as well as of the epidermal growth factor (EGF) receptor on 20 newly established human ovarian carcinoma cell lines. IFN gamma in concentrations of 10, 50 and 100 U/ml was used to study its antigen-modulatory effect, and at additional 1 U/ml and 1000 U/ml to assess its antiproliferative effect on the cells. The cells were incubated with IFN for 4 days. Two cell lines showed strong antiproliferative activity even at minimal doses (up to 50 U/ml). Intermediate growth inhibition between 34% and 84% was observed in 15 cell lines with higher doses. Three lines were resistant to IFN gamma. Independent of the antiproliferative effect, IFN gamma enhanced the expression of MHC class I and MHC class II in nearly all cell lines. Upregulation was also observed for most of the tumor-associated antigens (TAA) and EGF receptor expression. A down-regulation was noticed but rarely. The fact that IFN gamma showed an antiproliferative activity on the majority of the cell lines is of clinical relevance. The in vitro modulation of cell-surface determinants by IFN gamma warrants special attention. The enhanced expression of TAA and MHC antigens can improve immunogenicity of the tumor cells and may explain the therapeutic effects observed under IFN therapy in ovarian cancer. By contrast, enhanced expression of the EGF receptor, often associated with poor patient survival rates, may be an undesirable side-effect of IFN therapy.

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.

Multi-parameter flow cytometric quantitation of the expression of the tumor-associated antigen SM3 in normal and neoplastic ovarian tissues. A comparison with HMFG1 and HMFG2

SM3 is a monoclonal antibody that reacts with a peptide epitope in the core protein of polymorphic epithelial mucin. Multi-parameter flow cytometry was used to characterize the expression of SM3 and compare it with two related tumor-associated antigens, HMFG1 and HMFG2, in cell suspensions of 44 malignant ovarian tumors, 15 benign ovarian tumors, and 16 normal ovaries. Tumor-associated antigen expression was significantly higher in malignant ovarian neoplasms than in benign neoplasms (P less than 0.001 for all three antigens). SM3 was expressed more specifically in malignant than benign tumors but had a lower affinity than HMFG1 and HMFG2. Multi-parameter flow cytometric evaluation of a panel of monoclonal antibodies can be used to help in choosing the best antibody for immunohistochemistry, imaging, and eventually treatment of ovarian tumors.

Combined immunohistochemical study of tissue polypeptide antigen and cancer antigen 125 in human ovarian tumours

An indirect immunoperoxidase method was used to study the expression of tissue polypeptide antigen (TPA) and cancer antigen 125 (CA 125) in 47 benign and malignant ovarian tumours. Tissue polypeptide antigen and CA 125 antigen were expressed respectively in 22 (73%) and 16 (53%) of the 30 adenocarcinomas and in five (29%) and four (23%) of the 17 benign tumours. Co-expression of TPA and CA 125 antigen occurred in 12 (40%) malignant and four (23%) benign tumours. Ultrastructurally, TPA and CA 125 antigens were located at the cell surface and microvillous surfaces. Evaluation of combined TPA and CA 125 antigen results revealed a remarkable improvement in the positivity rate and a significant decrease (P less than 0.05) in the negativity rate of ovarian carcinomas as compared with the result of each one separately. These findings provide complementary evidence for the previous results on the plasma levels of TPA and CA 125 antigen and suggest that specific combinations of tumour markers may be more effective for the diagnosis and monitoring of ovarian carcinomas, than the use of any single marker.

Use of CA 125 monoclonal antibody to monitor patients with ovarian cancer

The monoclonal antibody (mAb) OC 125 reacts with an antigen on human ovarian carcinoma (OVCA) cells that is also shed into the body fluids and can be detected in patients' sera and/or ascites with a radioimmunometric assay. For the present study, serum CA 125 levels of patients (n = 36) with different stages of OVCA were investigated. Serum levels seem to correlate with tumor burden. In stages I and II (n = 12), 33% of patients were CA 125 positive, whereas 70% of stage III and IV patients (n = 24) were CA 125 positive. Mean serum levels were in 93 U/ml (stages I, II) and 279 U/ml (stages III, IV). CA 125 levels in ascites and in pleural effusions were manyfold higher than serum levels of the same patients (P less than 0.0001). Immunohistochemical investigations of CA 125 in different ovarian tumors (n = 91) revealed that 85% of malignant and 75% of borderline serous cystadenocarcinomas had detectable CA 125 surface expression. Furthermore, 71% of benign tumors showed the CA 125 epitope, whereas mucinous tumors were negative for this marker. One of six ovarian cancer cell lines was CA 125 positive, whereas in 6 of 11 patients, ascites-derived ovarian cancer cells (fresh and gradient isolated) were positive for this marker. The proportion of positive cells ranged from 10 to 90% in these samples. Intraperitoneal recombinant interferon-gamma (rIFN-gamma) therapy resulted in an increase in the number of cells reacting with CA 125. The results of monitoring in patients receiving different therapeutic regimens and/or agents demonstrate the usefulness of this marker.

Radioimmunoscintigraphy of ovarian cancer with 131-iodine labeled OC-125 antibody fragments

Radioimmunoscintigraphy (RIS) with 131I labeled OC-125 F(ab')2 monoclonal antibody fragments was prospectively studied in 43 women for primary diagnosis and follow up of ovarian cancer. Total body planar photoscans with a scintillation camera were performed one to seven days after antibody application and results were compared with operation and or CT examination. By the region of interest technique the tumor to non tumor tissue ratio (T/N) was calculated in vivo. Sensitivity in primary diagnosis was 100% (10/10), specificity 33% (1/3). For local recurrency, sensitivity was 86% (19/22), for metastatic loci 80% (17/21). Specificity was 75% and 50%. T/N ratio was in the rage from 1.3 to 2.8. Sensitivity for ovarian cancer is high in primary diagnosis and follow up. By the region of interest technique it is possible to detect small recurrencies and to presume peritoneal carcinosis. Antibody accumulations in diseases different from ovarian cancer however diminish specificity.

Serum placental-like alkaline phosphatase (PLAP): a novel combined enzyme linked immunoassay for monitoring ovarian cancer

A new combined enzyme linked immunoassay (ELISA) was developed to measure both serum placental-like alkaline phosphatase (PLAP) activity (PLAPA) and concentration (PLAPC) in the same microtitre plate using an Imperial Cancer Research Fund monoclonal antibody, designated H17E2. PLAP A and PLAP C were determined together with an existing marker, CA125 in 397 serial samples from 87 patients with epithelial ovarian cancer. Retrospective assessment showed the sensitivity to increase from 73% with CA125 alone, to 88% using CA125 and PLAP A, and to 93% with all three markers in 261 samples from the patients with known active disease at the time of sampling. When the results for all 397 samples were included in the analysis, however, the specificity, sensitivity, accuracy and predictive powers of this monoclonal antibody were not sufficiently high to assist in the prospective follow up of patients with ovarian cancer. This was due to a significant number of false positive and false negative results. Our data indicate that PLAP A or PLAP C estimation with H17E2 may, therefore, only be of value in the management of those patients with known active disease who are already known to be "marker positive" for this antigen.

Expression of CEA, CA125, CA19-9 and human milk fat globule membrane antigen in ovarian tumours

The expression of five different antigens in ovarian tumours was studied by means of an immunohistochemical test with anti-CEA, HMFG1 and HMFG2, NS19-9 and OC125 antibodies. Considerable variation was noted not only between different histological types and between tumours of one type but also between areas in a single tumour. HMFG1 and HMFG2 were the most reactive of all the antibodies; NS19-9 and OC125 were expressed by different populations of cells. It is concluded that specific combinations of antibodies are more effective both for the monitoring of ovarian cancer as well as for immunodiagnosis and treatment, than any single one used.