New tumor markers: CA125 and beyond

Comparison of serum human epididymis protein 4 with cancer antigen 125 as a tumor marker in patients with malignant and nonmalignant diseases

BACKGROUND

Human epididymis protein 4 (HE4), a precursor of human epididymis protein, has been proposed as a tumor marker for ovarian cancer. We evaluated HE4 in comparison with cancer antigen 125 (CA 125) in healthy individuals and in patients with benign and malignant diseases.

METHODS

CA 125 and HE4 serum concentrations were determined in 101 healthy individuals, 535 patients with benign pathologies (292 with benign gynecologic diseases) and 423 patients with malignant diseases (127 with ovarian cancers). CA 125 and HE4 cutoffs were 35 kU/L and 140 pmol/L, respectively.

RESULTS

HE4 and CA 125 results were abnormal in 1.1% and 9.9% of healthy individuals and in 12.3% and 37% of patients with benign diseases, respectively. Renal failure was the most common cause of increased HE4 in patients with benign disease, who had significantly higher HE4 concentrations (P = 0.001) than patients with other benign diseases. HE4 showed a higher specificity than CA 125 in patients with benign gynecologic diseases, with abnormal concentrations in 1.3% and 33.2% of the patients, respectively. HE-4 concentrations were abnormal primarily in gynecologic cancer and lung cancer. By contrast, CA 125 was increased in many different nonovarian malignancies, including nonepithelial tumors. A significantly higher area under the ROC curve was obtained with HE4 than with CA 125 for differentiating benign from malignant diseases (0.755 vs 0.643) and in the differential diagnosis of gynecologic diseases (0.874 vs 0.722).

CONCLUSIONS

HE4 has significantly higher diagnostic specificity than CA 125, and the combination of CA 125 and HE4 improved the detection of ovarian cancer in all stages and histological types.

HE4 a novel tumour marker for ovarian cancer: comparison with CA 125 and ROMA algorithm in patients with gynaecological diseases

The aim of this study is to evaluate a new tumour marker, HE4, in comparison with CA 125 and the Risk of Ovarian Malignancy Algorithm (ROMA) in healthy women and in patients with benign and malignant gynaecological diseases. CA 125 and HE4 serum levels were determined in 66 healthy women, 285 patients with benign gynaecological diseases (68 endometriosis, 56 myomas, 137 ovarian cysts and 24 with other diseases), 33 patients with non-active gynaecological cancer and 143 with active gynaecological cancer (111 ovarian cancers). CA 125 and HE4 cut-offs were 35 U/mL and 150 pmol/L, respectively. ROMA algorithm cut-off was 13.1 and 27.7 for premenopausal or postmenopausal women, respectively. HE4, CA 125 and ROMA results were abnormal in 1.5%, 13.6% and 25.8% of healthy women and in 1.1%, 30.2% and 12.3% of patients with benign diseases, respectively. Among patients with cancer, HE4 (in contrast to CA 125) had significantly higher concentrations in ovarian cancer than in other malignancies (p < 0.001). Tumour marker sensitivity in ovarian cancer was 79.3% for HE4, 82.9% for CA 125 and 90.1% for ROMA. Both tumour markers, HE4 and CA 125 were related to tumour stage and histological type, with the lowest concentrations in mucinous tumours. A significantly higher area under the ROC curve was obtained with ROMA and HE4 than with CA 125 in the differential diagnosis of benign gynaecological diseases versus malignant ovarian cancer (0.952, 0.936 and 0.853, respectively). Data from our population indicate that ROMA algorithm might be further improved if it is used only in patients with normal HE4 and abnormal CA 125 serum levels (cancer risk for this profile is 44.4%). ROMA algorithm in HE4 positive had a similar sensitivity and only increases the specificity by 3.2% compared to HE4 alone.

A comparison of the cyclic variation in serum levels of CA125 across the menstrual cycle using two commercial assays

BACKGROUND

Clinicians use CA125, a tumor-associated antigen, primarily to monitor epithelial ovarian cancer. However, CA125 lacks the sensitivity and specificity necessary for population-based screening in healthy women. The purpose of this study was to determine if serum concentrations of CA125 differed across the three phases of the menstrual cycle in healthy, premenopausal women using two commercially available assays.

METHODS

Healthy, Caucasian women between the ages of 18 and 39 were enrolled using strict criteria to exclude factors known to contribute to CA125 fluctuations. Menstrual cycle regularity was determined using calendars maintained by participants for 3 months. After cycle regularity was established, blood was drawn at three time points for CA125 determination using two commercial assays (i.e., Siemens and Panomics).

RESULTS

Regardless of the assay used, CA125 values were highest during menses. The CA125 values decreased 0.2 U/ml per day from menses to the end of the same cycle, which resulted in a net decrease of 5.8 U/ml across the cycle.

CONCLUSIONS

The two commercial assays for CA125 determination demonstrated good concordance in terms of reference ranges regardless of epitope differences. While CA125 levels changed over the course of the menstrual cycle, these changes may not be clinically significant in healthy women. This study is the first to control for factors known to contribute to CA125 elevations; to quantify a decrease in CA125 levels across the menstrual cycle; and to confirm concordance in the relative decreases in serum CA125 levels across the menstrual cycle between two frequently used commercial assays.

Ovarian cancer biomarkers: a focus on genomic and proteomic findings

Among the gynaecological malignancies, ovarian cancer is one of the neoplastic forms with the poorest prognosis and with the bad overall and disease-free survival rates than other gynaecological cancers; several studies, analyzing clinical data and pathological features on ovarian cancers, have focused on the identification of both diagnostic and prognostic markers for applications in clinical practice. High-throughput technologies have accelerated the process of biomarker discovery, but their validity should be still demonstrated by extensive researches on sensibility and sensitivity of ovarian cancer novel biomarkers, determining whether gene profiling and proteomics could help differentiate between patients with metastatic ovarian cancer and primary ovarian carcinomas, and their potential impact on management.

Therefore, considerable interest lies in identifying molecular prognostic biomarkers and protein indicators to guide treatment decisions and clinical follow up; the current state of knowledge about the potential clinical value of gene expression profiling in ovarian cancer is discussed, focusing on three main areas: distinguishing normal ovarian tissue from ovarian tumors, identifying different subtypes of ovarian cancer and identifying cancer likely to be responsive to therapy.

In this elaborate we discuss the use of novel molecules, discovered by proteomics and genomics approaches, as potential protein biomarkers in the management of ovarian cancer, to improve the anticancer therapy for malignant ovarian tumors and to monitor the clinical follow up.

An outlook on ovarian cancer and borderline ovarian tumors: focus on genomic and proteomic findings

Among the gynaecological malignancies, ovarian cancer is one of the neoplastic forms with the poorest prognosis and with the bad overall and disease-free survival rates than other gynaecological cancers. Ovarian tumors can be classified on the basis of the cells of origin in epithelial, stromal and germ cell tumors. Epithelial ovarian tumors display great histological heterogeneity and can be further subdivided into benign, intermediate or borderline, and invasive tumors. Several studies on ovarian tumors, have focused on the identification of both diagnostic and prognostic markers for applications in clinical practice. High-throughput technologies have accelerated the process of biomolecular study and genomic discovery; unfortunately, validity of these should be still demonstrated by extensive researches on sensibility and sensitivity of ovarian cancer novel biomarkers, determining whether gene profiling and proteomics could help differentiate between patients with metastatic ovarian cancer and primary ovarian carcinomas, and their potential impact on management. Therefore, considerable interest lies in identifying molecular and protein biomarkers and indicators to guide treatment decisions and clinical follow up. In this review, the current state of knowledge about the genoproteomic and potential clinical value of gene expression profiling in ovarian cancer and ovarian borderline tumors is discussed, focusing on three main areas: distinguishing normal ovarian tissue from ovarian cancers and borderline tumors, identifying different genotypes of ovarian tissue and identifying proteins linked to cancer or tumor development. By these targets, authors focus on the use of novel molecules, developed on the proteomics and genomics researches, as potential protein biomarkers in the management of ovarian cancer or borderline tumor, overlooking on current state of the art and on future perspectives of researches.

Prognostic and predictive relevance of CA-125 at primary surgery of ovarian cancer

INTRODUCTION

Despite radical surgery and chemotherapy, most patients with ovarian cancer develop recurrence and die due to progressive disease. To stratify patients for optimal therapy, prognostic and predictive factors are needed. We examined the role of pre- and postoperative CA-125 in this context.

METHODS

A total of 231 patients with primary ovarian cancer who presented for surgery at our institution between 1996 and 2004 were included in this study (25% FIGO stage I/II and 75% FIGO stage III/IV). The prognostic and predictive values of CA-125 serum concentrations before and after surgery as well as their correlation with clinicopathological variables were analyzed.

RESULTS

Median preoperative CA-125 was 61.6 kU/l (9-1,867 kU/l) in stage I/II patients and 533.15 kU/l (10-22,617 kU/l) in stage III/IV patients. Before surgery, 67% of stage I/II patients and 96% of stage III/IV patients had elevated CA-125 (>35 kU/l). There was a significant decrease in CA-125 after surgery in both patient cohorts (61.6-43.4 kU/l, P = 0.001 and 533.15-92.3 kU/l, P < 0.001, respectively). Furthermore, in stage III/IV patients with complete or so-called optimal (<1 cm residual disease) debulking, preoperative CA-125 levels were significantly lower than in patients with residual disease >1 cm (P = 0.01, P = 0.009, respectively). Neither CA-125 concentration before surgery nor its decrease was prognostically relevant for recurrence and survival at any stage. However, in stage III/IV patients, a high postoperative CA-125 was associated with shorter progression-free survival (P = 0.024).

CONCLUSIONS

Although CA-125 serum levels differ significantly before and after surgery in early and advanced-stage ovarian cancer and preoperative CA-125 values correlate with surgical outcome in advanced-stage disease, we could not determine a preoperative cutoff value for prediction of the surgical result. A prognostic relevance was only observed for postoperative CA-125 in stage III/IV patients.

Physician knowledge and awareness of CA-125 as a screen for ovarian cancer in the asymptomatic, average-risk population

Effective early detection strategies for ovarian cancer do not exist. Current screening guidelines recommend against routine screening using CA-125 alone or in combination with transvaginal ultrasonography (TVS). In this study, the authors used the 2008 DocStyles survey to measure clinician beliefs about the effectiveness of CA-125 and TVS in the asymptomatic, average-risk population in the United States. To assess the need for provider education, the authors used the 2008 HealthStyles survey to examine public awareness of CA-125. Of 1,250 physician respondents, 40.4% said both CA-125 and TVS were effective screens, and 28.3% said neither was an effective ovarian cancer screen in the asymptomatic, average-risk population. Obstetrician/gynecologists [OB/GYNs] more often had responses consistent with current guidelines: 56.5% of OB/GYNs, compared with 34.4% and 29.8% of family/general practitioners and internists, respectively, said neither CA-125 nor TVS was an effective screen. Almost one third of women surveyed reported having heard of CA-125, and about one tenth said they had the CA-125 test. These findings support the need for additional provider education. Educational efforts should include lack of evidence for, as well as the potential harms of, screening for ovarian cancer with CA-125.

An overview of biomarkers for the ovarian cancer diagnosis

Even though there are a lot of options in treating gynecological malignancies, ovarian cancer still remains a leading cause of death. Diagnosis at an early stage is the most important determinant of survival. Current diagnostic tools applied at clinics have had very limited success in early detection. Discovery of new diagnostic biomarkers/panels for early diagnosis of ovarian cancer is one of the main challenges of modern medicine. With the progress of techniques in genomics and proteomics, numerous molecular biomarkers/panels were identified and showed promise for ovarian cancer diagnosis, but still need further validation. This article summarizes various types of markers investigated by different strategies/technologies for the ovarian cancer diagnosis at present, including gene-, protein-based and emerging ovarian cancer indicators (such as microRNA-, metabolite-based). Before biomarker tests are translated for routine use, more researches, such as retrospective and prospective clinical trials, are needed to evaluate the overall clinical utility of the tests.

Combination of CA125 and RECAF biomarkers for early detection of ovarian cancer

Ovarian cancer can be cured in up to 90% of cases if diagnosed early. CA125, the most studied ovarian cancer biomarker, exhibits poor sensitivity for detecting early disease stages and low specificity to malignancy. RECAF, the alpha-fetoprotein receptor, is a wide-spectrum oncofetal antigen with clinical potential for cancer diagnosis, screening, and monitoring. This study evaluated the performance of RECAF as a diagnostic tool and the sensitivity of a combination of RECAF and CA125 to detect early stages of ovarian cancer at a cutoff resulting in 100% specificity among healthy women. This retrospective case–control study was designed to measure the serum levels of RECAF and CA125 in normal individuals (n = 106) and cancer patients stages I/II (RECAF, n = 32; CA125, n = 35) and III/IV (RECAF, n = 49; CA125, n = 51). A competitive chemiluminescence assay was developed to measure the circulating RECAF. To eliminate any false positives, we classified as positive any patient with a RECAF or a CA125 value higher than their respective 100% specificity cutoff. We have shown that RECAF discriminated cancer and healthy donors better than CA125, particularly in the early stages (AUC_RECAF = 0.96 and AUC_CA125 = 0.805). CA125 sensitivity was lower in the early stages than in the advance stages; RECAF sensitivity was high at all stages. A combination of CA125 and RECAF detected three out of four early-stage patients, with no false positives. In conclusion, the combination of RECAF and CA125 serum values provides the specificity and the sensitivity necessary to screen for ovarian cancer and in particular, to detect early stages of the disease.

Novel monoclonal antibodies against the proximal (carboxy-terminal) portions of MUC16

The CA125 antigen, recognized by the OC125 antibody, is a tissue-specific circulating antigen expressed in ovarian cancer. The CA125 antigen is encoded by the MUC16 gene cloned by Yin and Lloyd. The full-length gene describes a complex tethered mucin protein present primarily in a variety of gynecologic tissues, especially neoplasms. OC125 and other related antibodies react with glycosylation-dependent antigens present exclusively in the cleaved portion of the molecule. These antibodies are not useful as screening tools, nor can they detect the proximal residual MUC16 protein fragment after cleavage. This has limited its diagnostic and therapeutic applications. Using synthetic peptides, we raised novel-specific antibodies to the carboxy-terminal portion of MUC16 retained by the cell proximal to the putative cleavage site. These antibodies were characterized using fluorescence-activated cell-sorting analysis, enzyme-linked immunoassay, Western blot analysis, and immunohistochemistry. Each of the selected monoclonal antibodies was reactive against recombinant GST-ΔMUC16 protein and the MUC16-transfected SKOV3 cell line. Three antibodies, 4H11, 9C9, and 4A5 antibodies showed high affinities by Western blot analysis and saturation-binding studies of transfected-SKOV3 cells and displayed antibody internalization. Immunohistochemical positivity with novel antibody 4H11 was similar to OC125 but with important differences, including diffuse positivity in lobular breast cancer and a small percentage of OC125-negative ovarian carcinomas that showed intense and diffuse 4H11. Development of such antibodies may be useful for the characterization of MUC16 biology and allow for future studies in targeted therapy and diagnostics.

Potential markers for detection and monitoring of ovarian cancer

This paper reviews current screening techniques as well as novel biomarkers and their potential role in early detection of ovarian cancer. Ovarian cancer is one of the most common reproductive cancers and has the highest mortality rate amongst gynecologic cancers. Because most ovarian cancer diagnoses occur in the late stages of the disease, five-year survival rates fall below 20%. To improve survival rates and to lower mortality rates for ovarian cancer, improved detection at early stages of the disease is needed. Current screening approaches include tumor markers, ultrasound, or a combination. Efforts are underway to discover new biomarkers of ovarian cancer in order to surmount the obstacles in early-stage diagnosis. Among serum protein markers, HE4 and mesothelin can augment CA125 detection providing higher sensitivity and specificity due to the presence of these proteins in early-stage ovarian cancer. Detection testing that includes methylation of the MCJ gene and increased expression of vascular endothelial growth factor is correlated to poor prognosis and may predict patient survival outcome. Detection testing of biomarkers with long-term stability and combination panels of markers, will likely lead to effective screening strategies with high specificity and sensitivity for early detection of ovarian cancer.

Increased circulating hepatocyte growth factor (HGF): a marker of epithelial ovarian cancer and an indicator of poor prognosis

OBJECTIVE

Hepatocyte growth factor (HGF) has been described to be increased in different cancers. In the present study we wanted to investigate whether HGF in serum can distinguish between benign and malignant ovarian tumors, and whether serum HGF levels can predict the outcome in patients with ovarian carcinomas.

METHODS

We included 123 consecutive patients appointed for laparotomy due to a pelvic mass. Preoperative levels of serum cancer antigen 125 (CA 125), HGF and HGF activator (HGFA) were quantified with immunological methods. We performed immunohistochemical analyses of HGFα, HGFβ and the receptor c-Met. Five-year survival of patients with advanced disease (stage III and stage IV) was analyzed with the Kaplan-Meier method.

RESULTS

Sixty patients had ovarian carcinomas, 23 borderline tumors, and 40 benign ovarian tumors. Patients with ovarian carcinomas had significantly higher preoperative HGF and CA 125 serum levels than patients with benign ovarian tumors, and borderline tumors. Patients with borderline tumors had significantly higher CA 125 values than benign cases. A combination of CA 125 and HGF increased the specificity in predicting carcinoma. We observed abundant HGFα, HGFβ and c-Met expressions in all ovarian tumors. Patients with advanced disease and preoperative serum HGF values ≥2SD above reference value had a shorter disease-free survival than patients with advanced disease and serum HGF <2SD above reference value.

CONCLUSIONS

HGF in serum is an indicator of ovarian carcinoma in women with a pelvic mass, and of a poor prognosis in advanced ovarian cancer.

Circulating biomarker tissue kallikrein-related peptidase KLK5 impacts ovarian cancer patients' survival

BACKGROUND

Effective cancer biomarkers for early detection, prognosis, or therapy response prediction are urgently needed in ovarian cancer. Kallikrein-related peptidases, including KLK5, have been reported to play an important role in the course of the disease.

PATIENTS AND METHODS

KLK5 antigen content was determined by enzyme-linked immunosorbent assay in ovarian cancer patients' [FIGO (International Federation of Gynecology and Obstetrics) stages I-IV, n = 52] serum as well as ascitic fluid and compared with KLK5 content in serum of patients with benign ovarian tumors (n = 45).

RESULTS

KLK5 antigen content was significantly elevated in the serum of ovarian cancer patients compared with the serum of patients with benign ovarian tumors. Forty-two of 52 ovarian cancer serum samples, 42 of 43 benign ovarian tumor serum samples, and all 41 ascitic fluid samples were KLK5 positive. Elevated KLK5 antigen in serum and ascitic fluid of ovarian cancer patients was a prognostic factor for progression-free survival.

CONCLUSIONS

Our data support the finding that ovarian cancer patients release significant amounts of KLK5 into serum and ascitic fluid but KLK5 antigen is low in serum of patients with benign ovarian tumors. Increased serum and ascitic fluid KLK5 levels are associated with poor patient outcome, thus underlining the importance of KLK5 as a biomarker for early detection as well as for disease management in ovarian cancer.

Exploring the immunoproteome for ovarian cancer biomarker discovery

Most scientific efforts towards early detection of ovarian cancer are commonly focused on the discovery of tumour-associated antigens (TAA). Autologous antibodies against TAA, however, may serve as more sensitive diagnostic markers. They circulate in the blood before TAA and are usually more abundant than the TAAs themselves as a result of amplification through the humoral immune response. Accumulating evidence also suggests that a humoral response already exists during malignant transformation when aberrant gene expression is translated into premalignant cellular changes. This article reviews the current knowledge about autoantibodies against TAA in ovarian cancer and presents current immunoproteomic approaches for their detection.

Profiling signatures of ovarian cancer tumour suppression using 2D-DIGE and 2D-LC-MS/MS with tandem mass tagging

Epithelial ovarian cancer (EOC) is the most common form of gynaecological malignancy in the developed world and has a poor prognosis due to its late detection. Identifying molecular markers of the disease may provide novel approaches to screening and could enable targeted treatment and the design of novel therapies. Although blood is recognized as a highly important source of disease-related biomarkers, the complexity and dynamic range of protein abundance in body fluids has hampered proteomic biomarker discovery and alternative approaches using cell models may be more successful. Herein, we have utilized two cellular models of EOC, where transfer of normal chromosome 18 material into the EOC cell lines TOV-112D and TOV-21G induced in vitro and in vivo suppression of their tumourigenic phenotype. A combination of quantitative two-dimensional difference gel electrophoresis (2D-DIGE) and two-dimensional-liquid chromatography tandem mass spectrometry (2D-LC-MS/MS) with tandem mass tagging (TMT) was employed to examine the whole cell, secreted and crude membrane proteomes of the parental and hybrid cell models to identify differentially expressed proteins as potential markers of tumour suppression. Protein changes of interest were confirmed by immunoblotting in additional hybrid and revertant cell lines where incorporated chromosome 18 material was lost. One candidate marker was also tested in sera from a set of ovarian cancer cases and controls. We have identified a list of promising candidate biomarkers for further testing and functional characterization.

Screening for Ovarian Cancer

Background

Ovarian cancer remains the most deadly of the gynecologic cancers. It is difficult to diagnose until in advanced stages. An effective screening test may help to decrease mortality from ovarian cancer. Due to the low incidence of ovarian cancer in the general population, a good screening test must have high sensitivity and specificity to allow accurate detection without excessive false-positive results. Thus, effective screening for ovarian cancer has remained elusive.

Methods

Studies evaluating screening methods for ovarian cancer are reviewed. Screening methods investigated include ultrasound, CA-125, and serum proteins.

Results

The use of CA-125 or ultrasound alone does not result in adequate sensitivity or specificity for routine screening. A combination of the two modalities improves sensitivity, specificity, and positive predictive value. Using a combination of serum proteins may also improve sensitivity, specificity, and positive predictive value, but such studies have yet to be validated.

Conclusions

No effective screening methods for ovarian cancer that have been adequately validated are available. Routine screening for ovarian cancer in the general population is not currently recommended.

Distinctive DNA methylation patterns of cell-free plasma DNA in women with malignant ovarian tumors

OBJECTIVE

Epithelial ovarian carcinoma (OvCa) is rarely detected early, and it is also difficult to determine whether an adnexal mass is benign or malignant. Previously, we noted differences in methylation patterns of cell-free plasma DNA (cfpDNA) in women without disease compared to patients with OvCa. In this work, we investigated whether methylation patterns of cfpDNA can differentiate between benign and malignant tumors.

METHODS

Methylation patterns in cfpDNA were determined in three cohorts (30 samples each) using a microarray-based assay (MethDet 56). Principal component analysis, supervised clustering, linear discrimination analysis, and 25 rounds of 5-fold cross-validation were used to determine informative genes and assess the sensitivity and specificity of differentiating between OvCa vs. healthy control (HC), benign ovarian disease (mostly serous cystadenoma, BOD) vs. HC, and OvCa vs. BOD samples.

RESULTS

Differential methylation of three promoters (RASSF1A, CALCA, and EP300) differentiated between OvCa vs. HC with a sensitivity of 90.0% and a specificity of 86.7%. Three different promoters (BRCA1, CALCA, and CDKN1C) were informative for differentiating between BOD vs. HC, with a sensitivity of 90.0% and a specificity of 76.7%. Finally, two promoters (RASSF1A and PGR-PROX) were informative for differentiating between OvCa vs. BOD, with a sensitivity of 80.0% and a specificity of 73.3%.

CONCLUSIONS

This proof-of-principle data show that differential methylation of promoters in cfpDNA may be a useful biomarker to differentiate between certain benign and malignant ovarian tumors.

Impact of serum tumor marker determination on the management of women with borderline ovarian tumors: multivariate analysis of a French multicentre study

OBJECTIVE

To evaluate the contribution of preoperative serum tumor markers to manage borderline ovarian tumors (BOT).

STUDY DESIGN

Retrospective multicentre study including 317 BOT. Serum tumor marker levels of CA125, CA19-9, CEA, and CA15-3 were determined by radio-immunoassay.

RESULTS

Among 181 women with serous BOT and 136 women with mucinous BOT, respectively 55 of 114 (48.2%) and 38 of 91 (41.8%) had at least one abnormal value. Women with preoperative tumor marker assays were more likely to have radical treatment (p=0.0001), full staging (p=0.004), and intra-operative histology (p<0.0001). Women with at least one abnormal tumor marker were more likely to undergo laparotomy (p=0.007), to have intra-operative histology (p=0.04) and complete staging (p=0.0008). In multivariate analysis, first-line laparoscopy was associated with abnormal tumor marker levels (OR=9.63; 95%CI=1.40-66.39; p=0.02), while laparotomy was associated with large tumors, bilateral tumors, and ascitis visible on sonography.

CONCLUSION

Serum tumor marker assays modified both preoperative assessment and surgical management of BOT.

Status of tumor markers in epithelial ovarian cancer has there been any progress? A review

OBJECTIVE

The aim is to present an overview of tumor markers other than CA-125 that have been proposed for use in the diagnosis of epithelial ovarian cancer and explore molecular studies which have been used to identify genomic and proteomic changes associated with this malignancy for possible future development of more sensitive tumor markers.

METHODS

A Medline search was conducted to review published articles from American and European studies from 1990 to 2010, related to tumor markers for ovarian cancer. Different methods such as genomic, proteomic and transcriptional profiling were used to identify new tumor markers for clinical use.

RESULTS

A few of the newer tumor markers alone have demonstrated equal or slightly higher sensitivity to CA-125. Improved sensitivity and specificity have been reported using these new markers combined with CA-125.

CONCLUSION

Addition of new tumor markers as a compliment to CA-125 were associated with higher sensitivity and detection rates than either marker alone. However, the low prevalence of ovarian cancer necessitates a higher level of sensitivity and specificity that has still not been achieved if these biomarkers are used for diagnosis and monitoring the disease progress as a result of low positive predictive value.

Longitudinal monitoring of CA125 levels provides additional information about survival in ovarian cancer

Background

We investigated the prognostic impact of changes in serum CA125 levels during the first 3 months of therapy in ovarian cancer.

Methods

A case series of 170 ovarian cancer patients treated at Cancer Treatment Centers of America. Based on CA125 levels at baseline and 3 months, patients were classified into 4 groups: 1) Normal (0-35 U/ml) at baseline and three months; 2) High (>35 U/ml) at baseline, normal at three months; 3) Normal at baseline, high at 3 months; 4) High at baseline and three months. Kaplan Meier method was used to calculate survival across the 4 categories.

Results

Of 170 patients, 36 were newly diagnosed while 134 had received prior treatment. 25 had stage I disease at diagnosis, 15 stage II, 106 stage III and 14 stage IV. The median age at presentation was 54.2 years (range 23.1 - 82.5 years). At baseline, 31 patients had normal (0-35 U/ml) serum CA125 levels while 139 had high (>35 U/ml) levels. At 3 months, 59 had normal while 111 had high levels. Patients with a reduced CA125 at 3 months had a significantly better survival than those with increased CA125 at 3 months. Patients with normal values of CA125 at both baseline and 3 months had the best overall survival.

Conclusions

These data show that reduction in CA125 after 3 months of therapy is associated with better overall survival in ovarian cancer. Patients without a significant decline in CA125 after 3 months of therapy have a particularly poor prognosis.

Impact of expression differences of kallikrein-related peptidases and of uPA and PAI-1 between primary tumor and omentum metastasis in advanced ovarian cancer

BACKGROUND

Primary tumor levels of serine proteases of the kallikrein-related peptidases (KLK) family as well as urokinase-type plasminogen activator (uPA) and its inhibitor PAI-1 impact disease course in ovarian cancer. The changes in levels of these factors from primary tumor to omentum metastasis ('level differentials') could thus be associated with metastastic processes.

PATIENTS AND METHODS

Protein levels of seven tissue KLK (KLK5-8, 10, 11, 13), uPA, and PAI-1 were determined in extracts of primary tumor tissue and corresponding omentum metastasis of 54 ovarian cancer patients.

RESULTS

Higher level differentials of KLK5-8, 10-11, and uPA were associated with residual tumor >10 mm. Residual tumor and larger level differentials of KLK5-7, 10, and uPA were associated with disease progression in the whole cohort. Remarkably, level differentials of KLK5-8 and 10-11 strongly impacted disease progression even in patients with residual tumor mass ≤10 mm; hence, the observed impact of level differentials in KLK5-7 and 10 on disease progression was not simply attributable to their association with surgical success.

CONCLUSION

Since they impact both surgical outcome and survival in advanced ovarian cancer, measurement of level differentials could support clinical decisions on surgical and systemic therapy or help in patient selection for novel targeted therapies.

MUC16 expression and risk of adenocarcinoma metastases to peritoneum, pleura, leptomeninges, and brain

Approximately 5% to 15% of central nervous system metastases by solid tumors spread to the leptomeninges. Transmembrane MUC16 is thought to facilitate anchoring of metastases to other tissues particularly those expressing mesothelin such as pleura and peritoneum. Recently, we have demonstrated that mesothelin is also expressed in the leptomeninges. Mesothelin has a high affinity for MUC16 and mesothelin expressed by some adenocarcinomas. In this study, we evaluated MUC16 and mesothelin immunoreactivity by immunohistochemistry in 11 adenocarcinomas to the leptomeninges, 24 to mesothelin-negative brain, 8 metastases to mesothelin-expressing peritoneum/pleura, 22 to mesothelin-negative peripheral tissues, and 24 with no metastases. MUC16 was detected in 36% of leptomeningeal metastases and 10% of metastases to the brain. Adenocarcinoma metastases to mesothelin-expressing peritoneum or pleura exhibited extensive MUC16 in 75% of cases. In adenocarcinomas with local metastases to lymph nodes or no metastases, 53% or 38% had MUC16 immunoreactivity, respectively. Mesothelin-immunoreactivity was detected in 9% of metastases to the leptomeninges, 17% to the brain, none of the metastases to pleura/peritoneum, 50% of adenocarcinomas with local metastases to lymph nodes, etc, and 33% of adenocarcinomas without metastases. Mesothelin expression was significantly more common in nonmetastatic adenocarcinomas than in metastases to the pleura/peritoneum or leptomeninges. Our findings suggest that adenocarcinomas with MUC16 expression may have an increased risk for metastases to pleura/peritoneum but not the leptomeninges or brain.

Successful eradication of established peritoneal ovarian tumors in SCID-Beige mice following adoptive transfer of T cells genetically targeted to the MUC16 antigen

PURPOSE

Most patients diagnosed with ovarian cancer will ultimately die from their disease. For this reason, novel approaches to the treatment of this malignancy are needed. Adoptive transfer of a patient's own T cells, genetically modified ex vivo through the introduction of a gene encoding a chimeric antigen receptor (CAR) targeted to a tumor-associated antigen, is a novel approach to the treatment of ovarian cancer.

EXPERIMENTAL DESIGN

We have generated several CARs targeted to the retained extracellular domain of MUC16, termed MUC-CD, an antigen expressed on most ovarian carcinomas. We investigate the in vitro biology of human T cells retrovirally transduced to express these CARs by coculture assays on artificial antigen-presenting cells as well as by cytotoxicity and cytokine release assays using the human MUC-CD(+) ovarian tumor cell lines and primary patient tumor cells. Further, we assess the in vivo antitumor efficacy of MUC-CD-targeted T cells in SCID-Beige mice bearing peritoneal human MUC-CD(+) tumor cell lines.

RESULTS

CAR-modified, MUC-CD-targeted T cells exhibited efficient MUC-CD-specific cytolytic activity against both human ovarian cell and primary ovarian carcinoma cells in vitro. Furthermore, expanded MUC-CD-targeted T cells infused through either i.p. injection or i.v. infusion into SCID-Beige mice bearing orthotopic human MUC-CD(+) ovarian carcinoma tumors either delayed progression or fully eradicated disease.

CONCLUSION

These promising preclinical studies justify further investigation of MUC-CD-targeted T cells as a potential therapeutic approach for patients with high-risk MUC16(+) ovarian carcinomas.

Synthesis and structural characterization of the peptide epitope of the ovarian cancer biomarker CA125 (MUC16)

A highly conserved region of 21 amino acids flanked by cysteine residues, contained within a larger repeated domain, has been proposed to be the antibody-binding site in the ovarian cancer biomarker CA125 (MUC16). In this study solid-phase peptide synthesis with Fmoc protection chemistry was used to assemble a 21-mer peptide corresponding to the most frequently occurring antibody binding sequence in CA125. Potentially significant sequence variants were also synthesized. Peptide secondary structure was investigated using Fourier transform infrared spectroscopy, revealing the consensus sequence peptide to be largely unstructured at physiological pH whether the cysteine residues were reduced or were oxidized to form an intramolecular disulfide bond. Substitution of serine for proline at position 8 (P8S) results in β-sheet formation in peptides involved in intramolecular disulfide bonds. This β-sheet structure does not persist in peptides incapable of intramolecular disulfide bonding because of sequence nor in peptides treated with the reducing agent dithiothreitol. In CA125, P8S is predicted to occur in ∼25% of repeat domains, suggesting that this structural motif is a non-negligible contributor to overall structure and function. These findings suggest that future structural characterization efforts of CA125 should be especially mindful of the amino acid sequence and oxidation state of the protein.

CA125 in ovarian cancer

A quarter of a century since its discovery, circulating CA125 antigen is recommended for clinical use in the USA for ovarian cancer screening of high-risk women with ovaries, despite its limited sensitivity and specificity. Recent findings suggest that CA125 might also serve as a predictive marker for pre-invasive ovarian carcinoma. Methods to quantify circulating CA125 evolved toward sensitive and reliable double-determinant ELISA assays. The CA125 gene, MUC16, was cloned 20 years after the protein discovery and revealed a very complex and unusual glycoprotein structure, suggesting an immunological role. Recent evidence points toward CA125 function in the induction of materno-fetal tolerance through the alteration of natural killer phenotype. Two receptors for CA125 have been described: mesothelin and galectin-1. The specific location and functional proprieties of CA125 make it a therapeutic target of choice; clinical trials have demonstrated that anti-CA125 injections are well tolerated and suggest a potential survival benefit.

TIMP-1 and VEGF-165 serum concentration during first-line therapy of ovarian cancer patients

Background

Angiogenesis appears to play an important role in ovarian cancer. Vascular endothelial growth factor (VEGF) has recently been implicated as a therapeutic target in ovarian cancer. The tissue inhibitor of metalloproteinase 1 (TIMP-1) is involved in tissue invasion and angiogenesis. The application of serum TIMP-1 and VEGF to monitor primary therapy and predict clinical outcome of patients with ovarian cancer is unclear.

Methods

Patients with epithelial ovarian cancer who presented for primary surgery were included in this study. A total of 148 serum samples from 37 patients were analyzed. Samples were prospectively collected at 4 predefined time points: 1. before radical debulking surgery, 2. after surgery and before platinum/taxane based chemotherapy, 3. during chemotherapy, 4. after chemotherapy. Serum VEGF-165 and TIMP-1 as well as CA-125 were quantified by ELISA or ECLIA and correlation with response and long-term clinical outcome was analyzed.

Results

Serum levels of all markers changed substantially during first-line therapy. High CA-125 (p = 0.002), TIMP-1 (p = 0.007) and VEGF-165 (p = 0.02) after chemotherapy were associated with reduced overall survival. In addition, elevated CA-125 (p < 0.001) and VEGF-165 (p = 0.006) at this time point predicted poor progression-free survival. TIMP-1 and VEGF-165 were closely correlated at all time-points during therapy.

Conclusions

TIMP-1 and VEGF serum levels changed significantly during first-line therapy of ovarian cancer patients and predicted prognosis. These findings support the role of angiogenesis in ovarian cancer progression and the use of antiangiogenic therapy.

Development of a multimarker assay for early detection of ovarian cancer

PURPOSE

Early detection of ovarian cancer has great promise to improve clinical outcome.

PATIENTS AND METHODS

Ninety-six serum biomarkers were analyzed in sera from healthy women and from patients with ovarian cancer, benign pelvic tumors, and breast, colorectal, and lung cancers, using multiplex xMAP bead-based immunoassays. A Metropolis algorithm with Monte Carlo simulation (MMC) was used for analysis of the data.

RESULTS

A training set, including sera from 139 patients with early-stage ovarian cancer, 149 patients with late-stage ovarian cancer, and 1,102 healthy women, was analyzed with MMC algorithm and cross validation to identify an optimal biomarker panel discriminating early-stage cancer from healthy controls. The four-biomarker panel providing the highest diagnostic power of 86% sensitivity (SN) for early-stage and 93% SN for late-stage ovarian cancer at 98% specificity (SP) was comprised of CA-125, HE4, CEA, and VCAM-1. This model was applied to an independent blinded validation set consisting of sera from 44 patients with early-stage ovarian cancer, 124 patients with late-stage ovarian cancer, and 929 healthy women, providing unbiased estimates of 86% SN for stage I and II and 95% SN for stage III and IV disease at 98% SP. This panel was selective for ovarian cancer showing SN of 33% for benign pelvic disease, SN of 6% for breast cancer, SN of 0% for colorectal cancer, and SN of 36% for lung cancer.

CONCLUSION

A panel of CA-125, HE4, CEA, and VCAM-1, after additional validation, could serve as an initial stage in a screening strategy for epithelial ovarian cancer.

Serum CA 125 expression as a tumor marker for diagnosis and monitoring the clinical course of epithelioid sarcoma

PURPOSE

We report here, our experience of seven patients with epithelioid sarcomas and their serum CA 125 levels, as well as the results of an in vitro and in vivo study of CA 125 expression in epithelioid sarcoma cells and xenografts using three epithelioid sarcoma cell lines.

METHODS

In the clinical study, the serum CA 125 levels of seven epithelioid sarcoma patients were examined at multiple time points. Expression of the MUC16 gene that encodes the CA 125 sequence was examined using RT-PCR methods in three epithelioid sarcoma cell lines, FU-EPS-1, SFT-8606 and NEPS, and the CA 125 protein in each cell lysate was examined by Western blot using anti-CA 125 clone OC125 antibody. The concentration of CA 125 in the conditioned medium of each cell line was also measured.

RESULTS

In five of the seven epithelioid sarcoma patients, CA 125 levels reflected regression and progression of their disease. The CA 125 concentrations in the conditioned medium of FU-EPS-1, SFT-8606 and NEPS cells were 259, 252, and 6 U/ml, respectively. Strong expression of MUC16 mRNA was shown in FU-EPS-1 and SFT-8606 cells: correspondingly, a thick band was observed by Western blot analysis in only FU-EPS-1 and SFT-8606 cells.

CONCLUSION

We concluded that epithelioid sarcoma cells produce and secrete CA 125 into the blood serum and that the elevation of serum CA 125 correlates with disease progression. Therefore, measuring the serum CA 125 level should provide an useful index for diagnosing and monitoring the course of epithelioid sarcoma.

Use of a Symptom Index, CA125, and HE4 to predict ovarian cancer

BACKGROUND

Prior studies suggest that combining the Symptom Index (SI) with a serum HE4 test or a CA125 test may improve prediction of ovarian cancer. However, these three tests have not been evaluated in combination.

METHODS

A prospective case-control study design including 74 women with ovarian cancer and 137 healthy women was used with logistic regression analysis to evaluate the independent contributions of HE4 and CA125, and the SI to predict ovarian cancer status in a multivariate model. The diagnostic performance of various decision rules for combinations of these tests was assessed to evaluate potential use in predicting ovarian cancer.

RESULTS

The SI, HE4, and CA125 all made significant independent contributions to ovarian cancer prediction. A decision rule based on any one of the three tests being positive had a sensitivity of 95% with specificity of 80%. A rule based on any two of the three tests being positive had a sensitivity of 84% with a specificity of 98.5%. The SI alone had sensitivity of 64% with specificity of 88%. If the SI index is used to select women for CA125 and HE4 testing, specificity is 98.5% and sensitivity is 58% using the 2-of-3-positive decision rule.

CONCLUSIONS

A 2-of-3-positive decision rule yields acceptable specificity, and higher sensitivity when all 3 tests are performed than when the SI is used to select women for screening by CA125 and HE4. If positive predictive value is a high priority, testing by CA125 and HE4 prior to imaging may be warranted for women with ovarian cancer symptoms.

HE4: a new potential early biomarker for the recurrence of ovarian cancer

Human epididymis protein 4 (HE4) has recently been described as a new marker for the early diagnosis of ovarian cancer (OC). The objective of this study was to evaluate (a) the expression of HE4 vs. OC mucin CA125 in 32 patients with OC compared to 163 patients with other malignant or benign pathologies (b) HE4 as indicator of the recurrence of the disease in eight patients followed-up for 20 months after OC diagnosis. Serum HE4 and CA 125 levels were determined by ELISA and IRMA, respectively. At diagnosis, the patients with OC demonstrated high levels of both biomarkers with 96.9% sensitivity for HE4 and 85.7% for CA125. In the other pathologies there was 3.7% positivity for HE4 and 21.0% for CA125. The follow-up study showed an increase of HE4 5-8 months before CA125 increment in five of the eight patients, this early expression being strictly associated to a relapse of the disease. In conclusion, this study showed that HE4, compared to CA125, potentially is a better marker for the diagnosis of OC and could be an important early indicator of the recurrence of the disease.

Urinary angiostatin levels are elevated in patients with epithelial ovarian cancer

OBJECTIVE

The poor prognosis associated with epithelial ovarian cancer (EOC) is due to the lack of overt early symptoms and the absence of reliable diagnostic screening methods. Since many tumors over express angiogenic regulators, the purpose of this study was to determine whether elevated levels of the angiogenic or angiostatic molecules vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), endostatin (ES), and angiostatin (AS) were elevated in plasma and urine from patients with EOC.

METHODS

VEGF, HGF, ES and AS were assayed by ELISA in samples from pilot cohort consisting of healthy women (N=48; pre-menopausal N=23, post-menopausal N=25), women with benign gynecological disease (N=54), patients with primary peritoneal cancer (PP) (N=2) and EOC (N=35). Wherever possible, parallel serum samples were measured for CA125 levels by ELISA.

RESULTS

AS was the angioregulator that independently discriminated EOC patients from healthy individuals. Levels of urinary AS (uAS) from healthy individuals or women with benign gynecological disease averaged 21.4 ng/mL+/-3.7 and 41.5 ng/mL+/-8.8, respectively. In contrast, uAS averaged 115 ng/mL+/-39.2 and 276 ng/mL+/-45.8 from women with Stage I (N=6) and late stage (N=31) EOC, respectively. Furthermore, uAS was elevated in EOC patients regardless of tumor grade, stage, size, histological subtype, creatinine levels, menopausal status, or patient age, but appeared to complement CA125 measurements.

CONCLUSIONS

Levels of AS are elevated in the urine of patients with EOC and may be of diagnostic and/or prognostic clinical importance. Further studies of uAS as a biomarker for EOC alone or in combination with other markers are warranted.

Serum carbonic anhydrase IX during first-line therapy of ovarian cancer

OBJECTIVE

Carbonic anhydrase IX (CAIX) is primarily involved in maintaining the extracellular pH. It is overexpressed in a variety of tumors including ovarian cancer. To evaluate the potential prognostic and predictive role of serum CAIX for therapy response in ovarian cancer, we analyzed longitudinal serum samples.

METHODS

One hundred forty-eight serum samples from 37 patients with primary epithelial ovarian cancer were analyzed. Samples were prospectively collected at 4 time points: (1) before radical surgery, (2) after surgery and before platinum/taxane chemotherapy, (3) during chemotherapy, and (4) after chemotherapy. Serum CAIX was quantified by ELISA and expression in tumor tissue was verified by immunohistochemistry. Correlation with response and clinical outcome as well as the tumor marker CA-125 was analyzed.

RESULTS

Serum concentration of CAIX ranged between 30 and 1687 pg/mL and showed no significant changes during first-line therapy (median level before and after surgery 204 and 198 pg/mL, during and after chemotherapy 175 and 181 pg/mL). There was no association between serum CAIX and progression-free or overall survival. CA-125 decreased significantly after surgery (median serum level before and after surgery 413 and 84 kU/L, p<0.001) and further during and after first-line chemotherapy (median serum levels 21 and 15 kU/L, p<0.001). No intermarker correlation was observed.

CONCLUSIONS

CAIX is upregulated in ovarian cancer and serum CAIX could be a marker to stratify patients for therapy response. However, CAIX serum levels did not change significantly during first-line therapy and were not prognostically relevant. Based on the findings of the current study, CAIX cannot be recommended for therapy monitoring in this context.

Mucins in ovarian cancer diagnosis and therapy

Ovarian cancer is the most lethal gynecologic malignancy and the five-year survival rate is only 35% after diagnosis. Epithelial ovarian cancer is a highly metastatic disease characterized by widespread peritoneal dissemination and ascites. The death incidences from ovarian cancer could be significantly lowered by developing new methods for the early diagnosis and treatment of this fatal disease. Several potential markers have been identified recently. However, mucins are the most promising markers for ovarian cancer diagnosis. Mucins are large extracellular, heavily glycosylated proteins and their aberrant expression has been implicated in the pathogenesis of a variety of cancers, including ovarian cancer. This review will summarize known facts about the pathological and molecular characteristics of ovarian cancer, the current status of ovarian cancer markers, as well as general information about mucins, the putative role of mucins in the progression of ovarian cancer and their potential use for the early diagnosis and treatment of this disease.

Antifouling surface layers for improved signal-to-noise of particle-based immunoassays

A 10-fold improvement in the signal-to-noise (S/N) ratio of an optically encoded silica particle-based immunoassay was achieved through incorporating a protein resistant poly(ethylene glycol) (PEG) surface layer and optimizing antibody immobilization conditions. PEG was activated using 2,2,2-trifluoroethanesulfonyl chloride (tresyl) and required a minimum reaction time of 1.5 h. The activated PEG had a reactive half-life of approximately 5 h when stored in acidified dimethyl sulfoxide (DMSO). By increasing the protein incubation time and concentration, a maximum antibody loading on the particle surface of 1.6 x 10(-2) molecules per nm(2) was achieved. The assay S/N ratio was assessed using a multiplexed multicomponent optically encoded species-specific immunoassay. Encoded particles were covalently grafted or nonspecifically coated with either bovine or mouse IgG for the simultaneous detection of complementary anti-IgG "target" or uncomplementary anti-IgG "noise". The versatility and potential as a serum-based assay platform was demonstrated by immobilizing either a polyclonal antibody or an engineered single-chain variable fragment (scFv) capture probe on particles for the detection of the ovarian cancer biomarker, mesothelin (MSLN). The MLSN antigen was spiked into PBS buffer or 50% human serum. Both capture probe orientations, and media conditions showed similar low level detection limits of 5 ng/mL; however, a 40% decrease in maximum signal intensity was observed for assays run in 50% serum.

Characterization of humoral responses of ovarian cancer patients: antibody subclasses and antigenic components

OBJECTIVES

Current antigen-based diagnostic assays for ovarian cancers rely on intravasation of specific aberrantly expressed proteins and their achieving detectable steady-state concentrations, resulting in their inability to truly detect small early lesions. In contrast, tumor antigen immunorecognition is observed following initial transformation events. Our objective was to characterize humoral antitumor responses in terms of IgG subclasses generated and tumor antigens recognized.

METHODS

For patients with benign and malignant ovarian disease, tumor-reactive IgG subclasses were characterized by Western immunoblotting. Antigen recognition patterns were analyzed by 2-dimensional electrophoresis and proteins exhibiting shared or stage-specific recognition were defined by mass spectrometry (MS) sequencing.

RESULTS

Sera from ovarian cancer patients exhibited significantly greater immunoreactivities than either controls or women with benign disease. While late-stage patients recognized more proteins at greater intensity, stage-specific differential recognition patterns were observed in the IgG subclasses, with the greatest recognition appearing in IgG2 subclasses. Immunoreactivity in IgG2 and IgG3 from stage I and II patients appears to be most intense with nuclear antigens >40 kDa, while, in stage III patients, additional immunoreactivity was present in the <40 kDa components. Stage III patients also exhibited similar reaction with membrane antigens <40 kDa. Two-dimensional electrophoresis revealed 32 stage-linked antigenic differences with 11 in early-stage and 21 in late-stage ovarian cancer.

CONCLUSIONS

Owing to the timing and stability of humoral responses, quantitation of IgG subclasses recognizing specific tumor antigens provides superior biomarkers for early cancer identification and allows for differentiation of benign versus malignant ovarian masses and early- and late-stage cancers.

Primary ex vivo cultures of human fallopian tube epithelium as a model for serous ovarian carcinogenesis

Recent studies suggest that some serous ovarian carcinomas (SOCs) arise from the fallopian tube (FT) epithelium rather than the ovarian surface epithelium. This hypothesis places emphasis on the FT secretory epithelial cell as a cell-of-origin. Herein, we report the development of a novel ex vivo primary human FT epithelium culture system that faithfully recapitulates the in vivo epithelium, as shown by morphological, ultrastructural and immunophenotypic analyses. Mass spectrometry-based proteomics reveal that these cultures secrete proteins previously identified as biomarkers for ovarian cancer. We also use this culture system to study the response of the FT epithelium to genotoxic stress and find that the secretory cells exhibit a distinct response to DNA damage when compared with neighboring ciliated cells. The secretory cells show a limited ability to resolve the damage over time, potentially leaving them more susceptible to accumulation of additional mutagenic injury. This divergent response is confirmed with in situ studies using tissue samples, further supporting the use of this ex vivo culture system to investigate FT epithelial pathobiology. We anticipate that this novel culture system will facilitate the study of SOC pathogenesis, and propose that similar culture systems could be developed for other organ site-specific epithelia.

Potential use of circulating endothelial cells as a biomarker of renal cell carcinoma

Each year, renal cell carcinoma (RCC) accounts for significant mortality in the population. Whilst the disease is now being diagnosed earlier, determining patient prognosis remains a challenge. Current prognostic indicators, such as TNM stage, Fuhrman grade, and RCC subtype, are inadequate. Unlike several other malignancies, RCC lacks a biomarker that can stratify patients into high, intermediate, or low risk for developing metastases. Additionally, antiangiogenic therapy is currently offered to patients with metastatic disease, however, a biomarker to monitor treatment efficacy is lacking. Recent attention has focused on surrogate markers of tumor vascularization as a source of prognostic biomarkers, as tumor growth is ultimately dependent on neovascularization. Two cell populations of interest, circulating endothelial cells (CECs) and circulating endothelial progenitors (CEPs), have been demonstrated across several studies to contribute to tumor vascularization. Given these findings, studies have examined their utility as biomarkers of prognosis by correlating their levels with progression-free survival and prognostic determinants such as tumor volume and weight. However, their role in predicting prognosis in RCC, as well as their potential to act as markers of treatment efficacy in metastatic RCC, remains to be established. Previous studies on CECs and CEPs in the context of cancer will be outlined in this review.

Current status of mucins in the diagnosis and therapy of cancer

Mucins are the most abundant high molecular weight glycoproteins in mucus. Their nature and glycosylation content dictates the biochemical and biophysical properties of viscoelastic secretions, pointing out an important role in diverse biological functions, such as differentiation, cell adhesions, immune responses, and cell signaling. Mucins are expressed in tubular organs by specialized epithelial cells in the body. Their aberrant expression is well documented in a variety of inflammatory or malignant diseases. From a prognosis point of view, their expression and alterations in glycosylation are associated with the development and progression of malignant diseases. Therefore, mucins can be used as valuable markers to distinguish between normal and disease conditions. Indeed, this alteration in glycosylation patterns generates several epitopes in the oligosaccharide side chains that can be used as diagnostic and/or prognostic markers. Furthermore, these characteristic tumor-associated epitopes are extensively used as appropriate immunotargets of malignant epithelial cells. Therefore, in an effort to detect and treat cancer at the earliest stage possible, mucins are analyzed as potential markers of disease for diagnosis, progression, and for therapeutic purposes. In this review, we focused on the current status of the distribution of mucins in normal and pathologic conditions and their clinical use both in cancer diagnosis and therapeutics treatments.

A Proteomics Panel for Predicting Optimal Primary Cytoreduction in Stage III/IV Ovarian Cancer

The objective of this prospective study was to evaluate CA-125 and a 7-marker panel as predictors of incomplete primary cytoreduction in patients with stage III/IV ovarian cancer (OC). From September 2004 to January 2008, serum from 201 patients referred to surgery for a pelvic tumor was analyzed for CA-125. In addition, serum was analyzed for 7 biomarkers using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry. These biomarkers were combined into a single-valued ovarian-cancer-risk index (OvaRI). CA-125 and OvaRI were evaluated as predictors of cytoreduction in 75 stage III/IV patients using receiver operating characteristic curves.

Complete primary cytoreduction (no macroscopic residual disease) was achieved in 31% (23/75) of the patients. The area under the receiver operating characteristic curve was 0.66 for CA-125 and 0.75 for OvaRI.

The sensitivity and specificity of CA-125 for predicting incomplete cytoreduction were 71% (37/52) and 57% (13/23), respectively (P = 0.04). The sensitivity and specificity of OvaRI for predicting incomplete cytoreduction were 73% (38/52) and 70% (16/23), respectively (P = 0.001). In conclusion, CA-125 and an index of 7 biomarkers were found to be predictors of cytoreduction. However, future studies of biomarkers are anticipated to promote early diagnosis and provide prognostic information to guide treatment of OC patients. In addition, new biomarkers might also play a role in predicting outcome from primary surgery in OC patients.

Ovarian Cancer Screening and Early Detection

One of the most challenging issues in gynecologic oncology is the high mortality rate of ovarian cancer, largely due to detection of disease in advanced stages. Women with early-stage disease have a significantly improved survival rate and may not require chemotherapy. Thus, the issues to examine are whether there are methods to improve early detection, thereby resulting in a reduction in mortality. Several large, randomized, clinical trials have recently completed evaluating CA 125 and transvaginal sonography as effective strategies to accomplish this goal. These issues and the results of the recent trials will be reviewed in this article.

Current state of biomarker development for clinical application in epithelial ovarian cancer

Each year in the United States over 15,000 women die of epithelial ovarian cancer (EOC) and 22,000 are diagnosed with the disease. The incidence of ovarian cancer has remained stable over the past decade however, survival rates have improved steadily. Increases in survival rates can be attributed to the advances in surgical management, development of effective cytotoxic drugs and the route of administration of chemotherapy. Ovarian cancer survival rates could also be improved through screening and early detection. Disappointingly, effective screening methods have not been established and continue to be elusive. Historically the goal of a screening test was to achieve a positive predictive value (PPV) greater than 10% in order be considered cost effective and have an acceptable risk for the population being screened. Despite the inability of currently available screening algorithms to achieve the desired PPV there may be an advantage in producing a stage migration to lower stages at the time of diagnoses, thereby resulting in improved survival. Equally important recent studies have demonstrated that women who have their initial surgery performed by gynecologic oncologists, and women who have their surgeries at centers experienced in the treatment of ovarian cancer have higher survival rates. For these reasons it is essential that all women at high risk for ovarian cancer receive their initial care by gynecologic oncologists and at centers with multidisciplinary teams experienced in the optimal care of ovarian cancer patients. With this in mind, methods that facilitate the accurate triage of women who will ultimately be diagnosed with ovarian cancer could play a significant role in improving survival rates for these patients. This review article will examine the current state of biomarker use in ovarian cancer screening, risk assessment and for monitoring ovarian cancer patients.

Role of CA125 in predicting ovarian cancer survival - a review of the epidemiological literature

CA125 is the gold standard tumor marker in ovarian cancer. Serum level of CA125 is used to monitor response to chemotherapy, relapse, and disease progression in ovarian cancer patients. Thus, it is reasonable to investigate whether CA125 may have utility as a prognostic indicator as well in ovarian cancer. A large number of epidemiological studies have been carried out to this effect. This review summarizes all available epidemiological literature on the association between CA125 levels and survival in ovarian cancer. To place these studies in context, we provide some background information on CA125 and its role in ovarian cancer.

Patient-derived tumor-reactive antibodies as diagnostic markers for ovarian cancer

OBJECTIVE

Most ovarian cancers are diagnosed at advanced stage (67%) and prospects for significant improvement in survival reside in early diagnosis. Our objective was to validate our array assay for the identification of ovarian cancer based on quantitation of tumor-reactive IgG.

METHODS

The diagnostic array utilizes specific exosome-derived antigens to detect reactive IgG in patients' sera. Specific protein targets were isolated by immunoaffinity from exosomes derived from ovarian tumor cell lines. Sera were obtained from age-matched female volunteers, women with benign ovarian disease and with ovarian cancer. Immunoreactivity was also compared between exosomal proteins and their recombinant counterparts.

RESULTS

Sera from ovarian cancer patients exhibited significantly greater immunoreactivities than either normal controls or women with benign disease (both considered negative to all antigens tested). Reactivities with nucleophosmin, cathepsin D, p53, and SSX common antigen for patients with all stages of ovarian cancer were significantly higher than for controls and women with benign ovarian disease. Reactivity with placental type alkaline phosphatase, TAG 72, survivin, NY-ESO-1, GRP78, and Muc16 (CA125) allowed the differentiation between Stage III/IV and early stage ovarian cancer.

CONCLUSIONS

The quantitation of circulating tumor-reactive IgG can be used to identify the presence of ovarian cancer. The analyses of IgG recognition of specific exosomal antigens allows for the differentiation of women with benign ovarian masses from ovarian cancer, as well as distinguishing early and late stage ovarian cancers. Thus, the quantitative assessment of IgG reactive with specific tumor-derived exosomal proteins can be used as diagnostic markers for ovarian cancer.