Monitoring gene expression profile changes in ovarian carcinomas using cDNA microarray

Serum Human Epididymis Protein 4 as a Prognostic Predictor of New-Onset Heart Failure among Women after Acute Coronary Syndrome: A Single-Center Retrospective Study

INTRODUCTION

Little is known about the prognostic factors among women with acute coronary syndrome (ACS), partly due to the small number of women included in heart failure (HF) clinical trials. Human epididymis protein 4 (HE4) has been proven to be a new biomarker for acute and chronic HF over the years. We hypothesize that HE4 could be a promising predictor.

METHODS

This retrospective study analyzed data from Zhejiang Provincial People's Hospital. This study included 302 female patients with ACS between January 1, 2021, and December 1, 2021. The primary outcome was new-onset HF after ACS during the 12-month follow-up period. We used a logistic regression model to evaluate the association between serum HE4 levels and the incidence of HF. Serum HE4 levels were measured at baseline (within 24 h after admission).

RESULTS

Of the 302 female patients, 70 (23.2%) developed new-onset HF within 12 months. Serum HE4 levels in patients with adverse events were significantly higher than those in patients without events (8.9 [7.3-11.5] pmol/dL versus 5.9 [5.0-6.8] pmol/dL, p < 0.001). The levels of HE4, troponin I peak, left ventricular ejection fraction (LVEF), and estimated glomerular filtration rate (eGFR) were validated as independent predictors, with HE4 being the best laboratory predictor (area under the curve, 0.863; 95% confidence interval, 0.817-0.909). Serum HE4 concentrations of >6.93 pmol/dL distinguished patients at risk of HF with 82.9% sensitivity and 78.0% specificity (maximum Youden index J, 0.609). Moreover, HE4 levels were associated with an increased risk of HF.

DISCUSSION

We found a strong relationship between HE4 and the occurrence of HF after ACS among women, which might help identify patients at high risk of HF for whom close or intense management should be mandatory.

Serum Human Epididymis Protein 4 is a Potential Biomarker for Early Chronic Kidney Disease in an Obese Population

BACKGROUND

At present, it is difficult to clinically diagnose early chronic kidney disease (CKD). As a novel biomarker of malignancies in the female reproductive tract, the human epididymis protein 4 (HE4) has been reported to be significantly expressed in CKD patients.

AIM

We sought to assess whether HE4 can be used as a potential biomarker of early-stage CKD.

METHODS

The association between serum HE4 levels and CKD was analyzed in a retrospective study. A cohort of 506 patients with diabetic nephropathy who were hospitalized at Weihai Central Hospital, China, from January 2016 to November 2019 were included.

RESULTS

Serum HE4 levels were increased with increasing stage of CKD and significantly elevated in patients with CKD3-5 than CKD1-2 (P<0.001). In multivariate linear regression analyses, HE4 levels were strongly correlated with the estimated glomerular filtration rate (eGFR) in CKD patients (Model 2, P<0.001). HE4 (area under the curve; AUC=0.934) had better diagnostic value than serum creatinine (SCr; AUC=0.770) and blood urea nitrogen (BUN; AUC=0.647) for patients with early-stage CKD (CKD1-2). Additionally, HE4 levels increased with increasing glomerular lesion (GL) and renal interstitial fibrosis (IF)/tubular atrophy (TA) scores in 51 CKD patients (P<0.001).

CONCLUSION

Serum HE4 levels can be positively associated with the severity of CKD and are a very valuable clinical biomarker for predicting early-stage CKD.

Ovarian cancer and the evolution of subtype classifications using transcriptional profiling†

Ovarian cancer is a complex disease with multiple subtypes, each having distinct histopathologies and variable responses to treatment. This review highlights the technological milestones and the studies that have applied them to change our definitions of ovarian cancer. Over the past 50 years, technologies such as microarrays and next-generation sequencing have led to the discovery of molecular alterations that define each of the ovarian cancer subtypes and has enabled further subclassification of the most common subtype, high-grade serous ovarian cancer (HGSOC). Improvements in mutational profiling have provided valuable insight, such as the ubiquity of TP53 mutations in HGSOC tumors. However, the information derived from these technological advances has also revealed the immense heterogeneity of this disease, from variation between patients to compositional differences within single masses. In looking forward, the emerging technologies for single-cell and spatially resolved transcriptomics will allow us to better understand the cellular composition and structure of tumors and how these contribute to the molecular subtypes. Attempts to incorporate the complexities ovarian cancer has resulted in increasing sophistication of model systems, and the increased precision in molecular profiling of ovarian cancers has already led to the introduction of inhibitors of poly (ADP-ribose) polymerases as a new class of treatments for ovarian cancer with DNA repair deficiencies. Future endeavors to define increasingly accurate classification strategies for ovarian cancer subtypes will allow for confident prediction of disease progression and provide important insight into potentially targetable molecular mechanisms specific to each subtype.

Meta-Analysis of ERCC1 Protein Expression and Platinum Chemosensitivity in Non-Small-Cell Lung Cancer

Objective

To carry out the meta-analysis on the relationship between the expression of nucleotide excision repair cross-complementary enzyme 1 (ERCC1) protein and platinum chemosensitivity in patients with advanced non-small-cell lung cancer (NSCLC).

Methods

The literature on the expression of ERCC1 and platinum chemosensitivity in patients with advanced NSCLC was searched in computer, which was published from January 2009 to August 2019 on the databases such as China Journal Full-text Database (CJFD), China National Knowledge Infrastructure (CNKI), Wanfang Database, VIP, PubMed, EMBASE, and others. Stata 15.0 was used for statistical analysis, and ethnicity subgroup analysis was taken.

Results

Finally, 14 studies were included and 1337 patients were involved, of which 697 were ERCC1 positive, with a positive rate of 53.5%. The combined OR was 0.53 (95% CI: 0.30∼0.79; P < 0.01). The results of ethnicity subgroup analysis showed that there was no significant difference, with OR of 0.50 (95% CI: 0.31∼0.82; P=0.001) in Asian population and OR of 0.56 (95% CI: 0.30∼1.07) in Caucasian population.

Conclusion

The sensitivity to platinum chemotherapy in patients with ERCC1 protein negative expression in the middle and late stages of NSCLC is better than that in patients with positive expression, especially in Asian population. There is no correlation in Caucasian population.

Human Epididymis Protein 4 as an Indicator of Acute Heart Failure in Patients with Chronic Kidney Disease

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of death in patients with chronic kidney disease (CKD).

OBJECTIVE

To assess whether human epididymis protein 4 (HE4) can be useful in diagnosing acute heart failure (AHF) in patients with CKD.

METHODS

A cohort of 139 Han nationality female patients with CKD who were hospitalized at Renmin Hospital of Wuhan University, Wuhan, China from January 2015 through November 2017 were included.

RESULTS

Multivariable linear regression analysis showed that HE4 levels were significantly associated with N-terminal pro b-type natriuretic peptide (NT-proBNP) after adjustment of kidney function and other confounding factors. In the multivariate logistic regression analysis, HE4 was independently associated with AHF in patients with CKD (odds ratio, 2.120; 95% confidence interval, 1.034-4.344; P = .04). Moreover, according to the optimal cutoff value of 639.6 pmol per L, the area under the curve, sensitivity, and specificity of HE4 were 0.729, 74.2%, and 76.8%, respectively.

CONCLUSIONS

During hospitalization, HE4 maybe an useful indicator for diagnosing AHF in patients with CKD.

Diagnostic Performance of Serum Human Epididymis Protein 4 (HE4) for Prediction of Malignancy in Ovarian Masses

Background:

Early diagnosis of ovarian cancer is essential for long term disease control and mortality reduction. This has been achieved using tumor markers like cancer antigen 125 (CA-125) which is elevated in malignant as well as non-malignant conditions. This dilemma led to efforts towards development of newer markers like serum human epididymis secretory protein E4 (HE4). Present study aimed to evaluate role of HE4 in diagnosing ovarian cancers and comparing it with CA-125.

Methods:

Serum samples from 67 patients with ovarian cancer, 42 with benign ovarian masses and 26 healthy controls were collected preoperatively and tested for serum HE4 levels and CA-125 levels. Diagnostic performance of both tumor markers (HE4/CA-125) to diagnose malignancy in ovarian masses was calculated and compared to each other.

Results:

Mean CA-125 and HE4 levels were significantly higher in patients with ovarian cancer than in those with benign disease (p<0.001) or healthy controls (p< 0.001). Serum HE4 levels significantly increased in epithelial ovarian cancers when compared to non-epithelial ovarian cancers (p<0.01). Using benign control as comparison, receiver operating characteristic curve (ROC) was generated to predict a cut-off value for diagnosing malignancy for serum HE4 and CA-125. Compared to CA-125, HE4 had a similar sensitivity (83.6% vs. 85.10%) and higher specificity (100% vs. 90.48%); combination of serum HE4 and CA-125 improved the sensitivity to detect ovarian cancer to 92.54%. Sensitivity of HE4 to detect early stage ovarian cancer was superior to CA-125 (92.61% vs. 63.41%).

Conclusion:

Serum HE4, a novel tumor marker, discriminated epithelial ovarian cancer from benign ovarian masses. HE4 levels were related to the stage and histological types with the lowest levels in mucinous epithelial ovarian cancer and non-epithelial malignancy. Measuring serum HE4 levels alongwith CA-125 may provide higher accuracy for detecting epithelial ovarian cancer particularly in the early stages.

The contribution and perspectives of proteomics to uncover ovarian cancer tumor markers

Despite all the advances in understanding the mechanisms involved in ovarian cancer (OC) development, many aspects still need to be unraveled and understood. Tumor markers (TMs) are of special interest in this disease. Some aspects of clinical management of OC might be improved by the use of validated TMs, such as differentiating subtypes, defining the most appropriate treatment, monitoring the course of the disease, or predicting clinical outcome. The Food and Drug Administration (FDA) has approved a few TMs for OC: CA125 (cancer antigen 125; monitoring), HE4 (Human epididymis protein; monitoring), ROMA (Risk Of Malignancy Algorithm; HE4+CA125; prediction of malignancy) and OVA1 (Vermillion's first-generation Multivariate Index Assay [MIA]; prediction of malignancy). Proteomics can help advance the research in the field of TMs for OC. A variety of biological materials are being used in proteomic analysis, among them tumor tissues, interstitial fluids, tumor fluids, ascites, plasma, and ovarian cancer cell lines. However, the discovery and validation of new TMs for OC is still very challenging. The enormous heterogeneity of histological types of samples and the individual variability of patients (lifestyle, comorbidities, drug use, and family history) are difficult to overcome in research protocols. In this work, we sought to gather relevant information regarding TMs, OC, biological samples for proteomic analysis, as well as markers and algorithms approved by the FDA for use in clinical routine.

Potential role of the HOXD8 transcription factor in cisplatin resistance and tumour metastasis in advanced epithelial ovarian cancer

Few studies have examined the potential transcription factor (TF) simultaneously associated with cisplatin resistance and metastasis in ovarian cancer. To assess a related mechanism, a 345-channel protein/DNA array and transcriptional activity ELISA were performed to compare the TF activities in the cisplatin-sensitive SKOV3 and cisplatin-resistant SKOV3-DDP cells and in HO-8910 and the homologous highly metastatic HO-8910PM cells. In SKOV3-DDP vs. SKOV3 cells, 43 TFs were up-regulated, while 31 were down-regulated. In HO-8910PM vs. HO-8910 cells, 13 TFs were up-regulated, while 18 were down-regulated. In these two models, 4 TFs (HOXD8(1), HOXD8(2), RB, RFX1/2/3) were simultaneously up-regulated, and 9 TFs (SRE, FKHR, Angiotensinogen ANG-IRE, Pax2, CD28RC/NF-IL2B, HLF, CPE, CBFB and c-Ets-1) were down-regulated. HOXD8 mRNA and protein expression levels measured by reverse transcription polymerase chain reaction and ELISA, respectively, were significantly higher in SKOV3-DDP and HO-8910PM than in their corresponding cell lines (both p < 0.05). In 52 cases of different ovarian disease, the patients with recurrent and cisplatin-resistant ovarian cancer had higher expression levels of HOXD8 than patients with primary malignant tumours (p = 0.018, p = 0.001) or benign tumours (p = 0.001, p < 0.001). Taken together, these results suggest that HOXD8 is potentially associated with both cisplatin resistance and metastasis in advanced ovarian cancer.

HE4-test of urine and body fluids for diagnosis of gynecologic cancer

Serum epididymis protein 4 (HE4) level is a useful biomarker for the management of ovarian and endometrial cancer patients. Urine HE4-test, with its easier access than serum test, has emerged as a new method with promising application for the diagnosis of ovarian cancer. Areas covered: This review summarizes data regarding the detection and alteration of HE4 in urine samples collected from ovarian cancer patients and controls. The performance and limitation of the assay and potential direction of future study are also discussed. Expert commentary: Several studies have demonstrated an appreciable efficiency of urine HE4-test in the discrimination of ovarian cancer patients from general population. However, the data is based on small cohorts, and the performance of urine HE4-test need to be validated in larger groups. An algorithm incorporating other important factors may allow a quantitative assessment of cancer possibility. Future studies on the HE4 renal secretion and HE4 degradation dynamics in urine are also required for the establishment of standard protocols for the application of urine HE4-test in clinical settings.

Physiopathological factors affecting the diagnostic value of serum HE4-test for gynecologic malignancies

Serum epididymis protein 4 (HE4) represents a useful biomarker for the management of ovarian cancer and endometrial cancer patients. However, HE4 levels are affected by many physiopathological conditions or disorders that should be taken into consideration for an efficient application of this biomarker. Areas covered: The review provides an up-to-date reference on the multiple physiopathological factors that cause fluctuation of HE4 serum levels, and evaluates their impact on HE4-test in clinical settings. Potential mechanisms underlying the regulation of HE4 expression are also discussed. The review is based on data from literature search of PubMed and the author's opinions. Expert commentary: Studies have shown that physiopathological factors such as age, infection/inflammation, renal function, menopause and hormonal levels impose significant impacts on HE4 serum levels. HE4 amount shed into the circulation is related to HE4 expression and secretion by tumor as well as normal tissues, which is affected by cancer heterogeneity, vascular permeability, renal clearance and HE4 degradation. Investigation on interfering factors builds a basis for the construction of a quantitative logarithm for individualized application of HE4-test in clinical settings.

Transcriptome analysis of equine sarcoids

Equine sarcoids are the most commonly detected skin tumours in Equidae. In the present research, a comparative transcriptomic analysis was performed which aimed at looking inside a tumour biology and identification of the expression profile as a potential source of cancer specific genes useful as biomarkers. We have used Horse Gene Expression Microarray data from matched equine sarcoids and tumour-distant skin samples. In total, 901 significantly differentially expressed genes (DEGs) between lesional and healthy skin samples have been identified (fold change ≥ 2; P < 0.05). The large subset of DEGs, with decreased expression, was associated with a suppression of malignant transformation, whereas several overexpressed genes were involved in the processes associated with growth and progression of a tumour or immune system activity. Our results, as a first to date, showed comprehensive transcriptome analysis of skin tumour in horses and pinpointed significant pathways and genes related with oncogenesis processes.

Rapid quantitation of human epididymis protein 4 in human serum by amplified luminescent proximity homogeneous immunoassay (AlphaLISA)

A sensitive, rapid and homogeneous reaction measurement method for quantitation of human epididymis protein 4 (HE4) in human serum by amplified luminescent proximity homogeneous immunoassay (AlphaLISA) was described. Built on a sandwich-type immunoassay format, analytes in samples were captured by one biotinylated monoclonal antibody combining on the surface of streptavidin coated donor beads, and "sandwiched" by another monoclonal antibody coated on acceptor beads. The coefficient variations of the method were lower than 10%, and the recoveries were in the range of 90-110% for serum samples. A value of 0.88pmol/l was identified as the minimum detectable dose of the present method for HE4. Compared with the results from electrochemiluminescence immunoassay kit (Roche) in 170 serum samples, there was a satisfied correlation coefficient of 0.984. The present assay demonstrated high sensitivity, wider effective detection range and excellent reproducibility for quantitation of HE4 can be useful for early screening and prognosis evaluation of patients with ovarian cancer.

Global Gene Expression Profiling: A Complement to Conventional Histopathologic Analysis of Neoplasia

Transcriptional profiling of entire tumors has yielded considerable insight into the molecular mechanisms of heterogeneous cell populations within different types of neoplasms. The data thus acquired can be further refined by microdissection methods that enable the analyses of subpopulations of neoplastic cells. Separation of the various components of a neoplasm (i.e., stromal cells, inflammatory infiltrates, and blood vessels) has been problematic, primarily because of a paucity of tools for accurate microdissection. The advent of laser capture microdissection combined with powerful tools of linear amplification of RNA and high-throughput microarray-based assays have allowed the transcriptional mapping of intricate and highly complex networks within pure populations of neoplastic cells. With this approach, specific “molecular signatures” can be assigned to tumors of distinct or even similar histomorphology, thereby aiding the desired objective of pattern recognition, tumor classification, and prognostication. This review highlights the potential benefits of global gene expression profiling of tumor cells as a complement to conventional histopathologic analyses.

Serum human epididymis protein 4 (HE4) may be a better tumor marker in early lung cancer

BACKGROUND

Human epididymis protein 4 (HE4) had been shown to be an ideal biomarker in ovarian cancer. However, there were fewer reports on its application in lung cancer. We explored the diagnostic value of serum HE4 as a biomarker in early lung cancer by comparing it with other biomarkers.

METHODS

162 individuals including 112 cases of lung cancer at early stage and 50 healthy people as controls were enrolled. The serum concentrations of biomarkers were determined with the Roche Elecsys assays.

RESULTS

In comparison to the other biomarkers such as carcinoembryonic antigen (CEA), neuron-specific-enolase (NSE), serum cytokeratin 19 fragment (CYFRA 21-1) and progastrinreleasing peptide (proGRP), serum HE4 was one of the biomarkers with the highest sensitivity (43.8%) and specificity (95.0%) for early lung cancer diagnosis. In terms of histological results, serum HE4 was the best biomarker both in adenocarcinoma (AC) and squamous carcinoma (SC), and serum proGRP was the best in small cell lung cancer (SCLC). The combination of proGRP, NSE and HE4 could determine the histological type of lung cancer with a very high accuracy of 93.8%.

CONCLUSIONS

These findings suggested that serum HE4 was a better biomarker in early lung cancer than other frequently-used biomarkers.

Application of chemical biology in target identification and drug discovery

Drug discovery and development is vital to the well-being of mankind and sustainability of the pharmaceutical industry. Using chemical biology approaches to discover drug leads has become a widely accepted path partially because of the completion of the Human Genome Project. Chemical biology mainly solves biological problems through searching previously unknown targets for pharmacologically active small molecules or finding ligands for well-defined drug targets. It is a powerful tool to study how these small molecules interact with their respective targets, as well as their roles in signal transduction, molecular recognition and cell functions. There have been an increasing number of new therapeutic targets being identified and subsequently validated as a result of advances in functional genomics, which in turn led to the discovery of numerous active small molecules via a variety of high-throughput screening initiatives. In this review, we highlight some applications of chemical biology in the context of drug discovery.

Detection of the HE4 protein in urine as a biomarker for ovarian neoplasms: Clinical correlates

OBJECTIVES

To measure HE4 levels in urine from normal donors, patients with LMP tumors and ovarian cancer patients and to correlate levels with clinical factors in ovarian cancer patients.

METHODS

Archived samples from controls, patients with LMP tumors and ovarian cancer were tested using commercial assays, including serially collected serum and urine samples from women treated for stage III/IV serous ovarian cancer.

RESULTS

Five of 6 patients with stage I/II and 26 of 36 stage III/IV serous ovarian cancer patients had HE4-positive urines, similar to serum samples (4 of 5 stage I/II and 26 of 34 stage III/IV) when tested at the same level of specificity (95%). Urine HE4 was more sensitive in LMP tumors: 9 of 32 urines (28%) HE4-positive versus 3 of 68 sera (4.4%, p=0.002). Mean levels of serum CA125 and HE4 decreased comparably in patients during initial treatment regardless of their primary platinum response, but mean urine HE4 levels decreased only 7% in primary platinum resistant patients while decreasing 68% in those who were sensitive. By 7months after diagnosis, urine HE4 levels were higher in primary platinum resistant patients compared to those who proved to be sensitive (p=0.051) and persisted 12months after diagnosis (p=0.014). HE4 values in urine also became positive in advance of clinical recurrence in several women while serum HE4 and serum CA-125 remained normal.

CONCLUSIONS

Measuring HE4 in urine complements serum assays for the detection of ovarian cancer and may allow identification of patients at high risk for primary platinum resistance.

Human epididymis protein 4 in association with Annexin II promotes invasion and metastasis of ovarian cancer cells

BACKGROUND

The objective of the present study was to identify human epididymis protein 4 (HE4) interacting proteins and explore the mechanisms underlying their effect on ovarian cancer cell invasion and metastasis.

METHODS

HE4 interacting proteins were identified by mass spectrometry and validated by co-immunoprecipitation and pull-down assays. The scratch test, the Transwell assay and animal experiments were used to assess the invasive and metastatic abilities of ovarian cancer cells before and after transfection and HE4 protein treatment. HE4 and annexin II protein expression in epithelial ovarian tissues was detected by immunohistochemistry, and the relation between their expression levels was examined.

RESULTS

Annexin II was identified as an HE4 interacting protein. HE4 and annexin II binding interaction promoted ovarian cancer cell invasion and metastasis. HE4 and annexin II expression levels were significantly higher in malignant epithelial ovarian tissues than in benign and normal epithelial ovarian tissues, and they were higher in tissues with lymph node metastases than in those without. HE4 gene interference downregulated the expression of MAPK and the FOCAL adhesion signaling pathway-associated molecules MKNK2 and LAMB2, and HE4 protein supplementation reversed this effect.

CONCLUSION

The binding interaction between HE4 and annexin II activates the MAPK and FOCAL adhesion signaling pathways, promoting ovarian cancer cell invasion and metastasis.

Human epididymis protein 4 (HE4) in laboratory medicine and an algorithm in renal disorders

Over the past three decades, cancer antigen (CA) 125 has been utilized for monitoring women who were treated for ovarian cancer. However, this tumor marker showed several limitations such as false elevation in benign pelvic diseases and, in turn, no alterations in ovarian tumors at early stages with a relatively high ratio. For more than ten years, the human epididymis protein 4 (HE4) has become available for the routine laboratory repertoire, showing a higher sensitivity and specificity compared to that of CA125 in ovarian malignancies, but also in other types of tumors based on recently accumulated clinical data. Despite its remarkable diagnostic characteristics, in certain cases, the evaluation of HE4 results may be problematic when patients suffer from additional conditions that may alter HE4 level. Besides the direct effects of age and smoking, menopause status and decreased renal function also show a substantial impact on HE4 values, which should be considered in each patient. For this purpose, we attempted to create a new formula and an algorithm that may be helpful to predict the probability of the presence of ovarian tumor by using the concentrations of HE4 and CA125.

Diagnosis and preoperative predictive value of serum HE4 concentrations for optimal debulking in epithelial ovarian cancer

The aim of this study was to evaluate serum human epididymis protein 4 (HE4) concentrations for the diagnosis and preoperative prediction of optimal debulking in epithelial ovarian cancer. The concentrations of serum HE4 and CA125 in 180 epithelial ovarian cancer patients, 40 benign ovarian tumor patients and 40 healthy female subjects were determined using enzyme-linked immunosorbent assays (ELISAs). The value of determining the serum HE4 concentrations for the diagnosis and preoperative prediction of optimal debulking in epithelial ovarian cancer was also analyzed. The concentration of serum HE4 was 355.2±221.29 pmol/l in ovarian cancer, 43.86±20.87 pmol/l in benign ovarian tumors and 30.22±9.64 pmol/l in healthy individuals, respectively. The serum HE4 levels of patients with ovarian cancer were significantly higher compared with those in the other two groups (P<0.01), although there were no statistically significant differences (P>0.05) between the benign ovarian tumors and healthy individuals. The maximum diagnostic value was identified at an HE4 serum concentration of 67.52 pmol/l and the sensitivity and specificity were 84 and 96%, respectively. The area under the ROC curve was 0.944 (95% CI, 0.912-0.976; P<0.001) and the κ value of the diagnosis of epithelial ovarian cancer according to HE4 was 0.814 (P=0.000). The demarcation criterion was 600 pmol/l, where a value >600 mol/l indicates a lower possibility of optimal debulking. HE4 predicted that the sensitivity of the incomplete cytoreductive surgery was 77% and specificity was 32%. The concentration of serum HE4 is a useful marker for diagnosis and preoperative prediction for the ideal tumor cytoreductive surgery in epithelial ovarian cancer.

The prognostic and predictive value of combined HE4 and CA-125 in ovarian cancer patients

OBJECTIVE

A risk-of-ovarian-malignancy algorithm (ROMA) based on human epididymis protein 4 (HE4) and CA-125 has been reported to categorize women with a pelvic mass into high or low risk of ovarian malignancy. Originally, the ROMA score was developed for diagnostic purposes and the clinical application of HE4 for other purposes such as a predictor of survival or platinum resistance has not been extensively investigated. The objective of the present study was to evaluate the prognostic importance of prechemotherapy combined levels of HE4 and CA-125 and prediction of platinum resistance. Furthermore, we wanted to investigate the dynamics of the markers during treatment.

MATERIALS AND METHODS

Serum from 137 patients with newly diagnosed serous ovarian cancer was analyzed for CA-125 and HE4 using ELISAs in a training data set. Patients with high levels (upper third percentiles) of both HE4 and CA-125 were classified as high-risk patients. Data were validated in an independent data set of an additional 94 patients. HE4 and CA-125 were also analyzed at all cycles of subsequent chemotherapy.

RESULTS

The combined score of HE4 and CA-125 was highly predictive of both progression-free and overall survival in univariate as well as multivariate survival analysis. Values in the upper third percentiles (66th) were significantly associated with decreased progression-free and overall survival in both the training and in the validation set (P < 0.05 in all analyses).The positive predictive value in relation to platinum resistance was higher for the combination of markers than for the markers individually. The positive predictive values were 64.3% and 60.7% for combined CA-125/HE4 in the training and validation sets, respectively.

CONCLUSIONS

The combination of HE4 and CA-125 levels at baseline just before initiation of chemotherapy was significantly associated with decreased progression-free and overall survival and to some extent with platinum resistance.

Human epididymis protein 4 in cancer diagnostics: a promising and reliable tumor marker

Human epididymis protein 4 (HE4) is a member of the "four-disulfide core" family that comprises a heterogeneous group of small acid- and heat-stable proteins of divergent function. Although there is an exponential growth of evidence that HE4 is a valuable tumor marker for ovarian malignancies, the exploration of the usefulness of this glycoprotein in the large tumor landscape is still ongoing. Enzyme-linked immunosorbent assay, chemiluminescent microparticle immunoassay, and bead-based array system are the preferred analytical methods for measuring HE4 concentration. Serum and urinary HE4 levels appear to be more affected by carcinogenesis than by other pathologic processes. Apart from the malignancy itself, histological type of cancer, cancer stage, and menopausal status affects HE4 concentration. An important objective in nowadays research remains the development of a tumor marker panel with a sufficient accuracy for risk assessment, early diagnosis, prognosis, and response to therapeutic treatment of cancer.

A novel gene expression index (GEI) with software support for comparing microarray gene signatures

This study was aimed to examine the validity of commonly used statistical tests for comparison of expression data from simulated and real gene signatures as well as pathway-characterized gene sets. A novel algorithm based on 10 sub-gradations (5 for up- and 5 for down-regulation) of fold-changes has been designed and testified using an Excel add-in software support. Our findings showed the limitations of conventional statistics for comparing the microarray gene expression data. However, the newly introduced Gene Expression Index (GEI) appeared to be more robust and straightforward for two-group comparison of normalized data. The software automation simplifies the task and the results are displayed in a comprehensive format including a color-coded bar showing the intensity of cumulative gene expression.

An gene expression pattern

DNA microarray technology has become a powerful tool in the arsenal of the molecular biologist. Capitalizing on high-precision robotics and the wealth of DNA sequences annotated from the genomes of a large number of organisms, the manufacture of microarrays is now possible for the average academic laboratory with the funds and motivation. Microarray production requires attention to both biological and physical resources, including DNA libraries, robotics, and qualified personnel. Although the fabrication of microarrays is a very labor-intensive process, production of quality microarrays individually tailored on a project-by-project basis will help researchers shed light on future scientific questions.

From bench to bedside: discovery of ovarian cancer biomarkers using high-throughput technologies in the past decade

Ovarian cancer is the most lethal gynecological malignancy and survival of this disease has remained relatively unchanged over the past 30 years. A contributing factor to this has been the lack of reliable biomarkers for the clinical management of ovarian cancer. Rapid advances in high-throughput technologies over the past decade has allowed for new and exciting opportunities for biomarker discovery in the field of ovarian cancer, especially with respect to serum biomarkers that can be used for various clinical applications. This review highlights the major genomic and proteomic studies dedicated to ovarian cancer biomarker discovery over the past decade. An emphasis will be placed on the HE4, Risk of Malignancy Algorithm (ROMA) and OVA1™ serum-based tests/algorithms that have recently been approved by the US FDA as ovarian cancer biomarkers.

The long journey of cancer biomarkers from the bench to the clinic

BACKGROUND

Protein cancer biomarkers serve multiple clinical purposes, both early and late, during disease progression. The search for new and better biomarkers has become an integral component of contemporary cancer research. However, the number of new biomarkers cleared by the US Food and Drug Administration has declined substantially over the last 10 years, raising concerns regarding the efficiency of the biomarker-development pipeline.

CONTENT

We describe different clinical uses of cancer biomarkers and their performance requirements. We also present examples of protein cancer biomarkers currently in clinical use and their limitations. The major barriers that candidate biomarkers need to overcome to reach the clinic are addressed. Finally, the long and arduous journey of a protein cancer biomarker from the bench to the clinic is outlined with an example.

SUMMARY

The journey of a protein biomarker from the bench to the clinic is long and challenging. Every step needs to be meticulously planned and executed to succeed. The history of clinically useful biomarkers suggests that at least a decade is required for the transition of a marker from the bench to the bedside. Therefore, it may be too early to expect that the new technological advances will catalyze the anticipated biomarker revolution any time soon.

TUMOR CLASSIFICATION BASED ON INDEPENDENT COMPONENT ANALYSIS

This paper proposes a new method for tumor classification using gene expression data, which mainly contains three steps. Firstly, the original DNA microarray gene expression data are selected using t-statistics. Secondly, the selected genes are modeled by Independent Component Analysis (ICA). Finally, Support Vector Machine (SVM) is used to classify the modeling data. To show the validity of the proposed method, we apply it to classify two DNA microarray data sets involving various human normal and tumor tissue samples. The experimental results show that the method is efficient and feasible.

Prognostic impact of prechemotherapy serum levels of HER2, CA125, and HE4 in ovarian cancer patients

OBJECTIVE

Human epididymis protein 4 (HE4) has attracted a lot of interest as a relatively novel biomarker for ovarian carcinoma. Research focus has been directed at HE4 as a diagnostic tool with potential for better triage of women with adnexal masses but the prognostic aspect of HE4 in ovarian cancer patients remains to be elucidated. The aim of the present study was to investigate the prognostic value of prechemotherapy serum HER2, cancer antigen 125 (CA125), and HE4 levels in ovarian cancer patients receiving standard combination chemotherapy.

METHODS

Serum from 139 patients with newly diagnosed ovarian cancer was analyzed for HER2, CA125, and HE4 using enzyme-linked immunosorbent assay assays. Samples were collected just before first-line chemotherapy, and all patients were treated with carboplatin-paclitaxel combination chemotherapy.

RESULTS

Increasing levels of serum HE4 (grouped into quartiles) was significantly associated with worse progression-free survival (PFS) (P < 10) and overall survival (P < 10). After adjustment in the Cox model, HE4 serum levels remained an independent prognostic parameter for PFS, with a hazard ratio of 1.77 (95% confidence interval, 1.03-3.04; P = 0.040) for patients with HE4 levels above the median compared with patients with HE4 levels below the median. The shorter PFS for patients with high levels of HE4 also translated into an independent significant difference in overall survival (hazard ratio, 3.17 [95% confidence interval, 1.41-7.10]; P = 0.005).Serum HER2 and CA125 levels did not demonstrate an independent prognostic value.

CONCLUSIONS

High levels of serum HE4 is a strong and independent indicator of worse prognosis in epithelial ovarian cancer patients.

Serum HE4 as a diagnostic and prognostic marker for lung cancer

We evaluated the diagnostic and prognostic efficacy of human epididymis protein 4 (HE4) for lung cancer patients by using our novel enzyme-linked immunosorbent assay (ELISA) system. We measured serum HE4 levels of cancer patients including 49 lung cancer and 18 ovarian cancer patients. Furthermore, we evaluated the relationship between serum HE4 levels and overall survival after chemotherapy of 24 lung cancer patients. Serum HE4 levels were significantly higher for non-small, small cell lung cancer and ovarian cancer patients than for healthy controls. The area under the receiver operating characteristic curve (AUC) was calculated for differentiation of lung cancer patients and healthy controls. AUC for serum HE4 was 0.988 for differentiating lung cancer patients from healthy controls, with a cutoff value of 6.56 ng/ml (sensitivity = 89.8%, specificity = 100%). Serum HE4 levels were elevated in 36/40 (90.0%) non-small cell lung cancer patients, 8/9 (88.9%) small cell lung cancer patients and 8/18 (44.4%) ovarian cancer patients. High levels of serum HE4 (>15 ng/ml) after chemotherapy were significantly correlated with worse overall survival after the treatment. These findings suggest that serum HE4 is a potential diagnostic and prognostic marker for lung cancer patients.

Changes in gene expression associated with reproductive maturation in wild female baboons

Changes in gene expression during development play an important role in shaping morphological and behavioral differences, including between humans and nonhuman primates. Although many of the most striking developmental changes occur during early development, reproductive maturation represents another critical window in primate life history. However, this process is difficult to study at the molecular level in natural primate populations. Here, we took advantage of ovarian samples made available through an unusual episode of human-wildlife conflict to identify genes that are important in this process. Specifically, we used RNA sequencing (RNA-Seq) to compare genome-wide gene expression patterns in the ovarian tissue of juvenile and adult female baboons from Amboseli National Park, Kenya. We combined this information with prior evidence of selection occurring on two primate lineages (human and chimpanzee). We found that in cases in which genes were both differentially expressed over the course of ovarian maturation and also linked to lineage-specific selection this selective signature was much more likely to occur in regulatory regions than in coding regions. These results suggest that adaptive change in the development of the primate ovary may be largely driven at the mechanistic level by selection on gene regulation, potentially in relationship to the physiology or timing of female reproductive maturation.

Human epididymis protein 4 offers superior specificity in the differentiation of benign and malignant adnexal masses in premenopausal women

OBJECTIVE

We sought to assess the ability of human epididymis protein 4 (HE4) and CA-125 to distinguish among benign, borderline, and malignant pelvic masses in premenopausal women.

STUDY DESIGN

We conducted a subset analysis of data from a prospective clinical trial that enrolled women undergoing surgery for an adnexal mass. Diagnostic performance of CA-125 and HE4 for epithelial ovarian cancer (EOC) detection in premenopausal women was determined.

RESULTS

Of 229 premenopausal patients, 195 (85%) had benign masses, 18 (8%) had EOC, and 16 (7%) had borderline ovarian tumor. The sensitivity of CA-125 and HE4 for EOC detection was 83.3% and 88.9%, respectively. The specificity of CA-125 and HE4 was 59.5% and 91.8%, respectively. A normal HE4 level ruled out invasive cancer in 98% of women with an elevated CA-125.

CONCLUSION

HE4 offers superior specificity compared to CA-125 for the differentiation of benign and malignant adnexal masses in premenopausal women.

Current gene expression studies in esophageal carcinoma

Esophageal carcinoma is one of the deadliest cancers with highly aggressive potency, ranking as the sixth most common cancer among males and ninth most common cancer among females globally. Due to metastasis and invasion of surrounding tissues in early stage, the 5-year overall survival rate (14%) of esophageal cancer remains poor, even in comparison with the dismal survival rates (4%) from the 1970s. Numerous genes and proteins with abnormal expression and function involve in the pathogenesis of esophageal cancer, but the concrete process remains unclear. Microarray technique has been applied to investigating esophageal cancer. Many gene expression studies have been undertaken to look at the specific patterns of gene transcript levels in esophageal cancer. Human tissues and cell lines were used in these geneprofiling studies and a very valuable and interesting set of data has resulted from various microarray experiments. These expression studies have provided increased understanding of the complex pathological mechanisms involved in esophageal cancer. The eventual goal of microarray is to discover new markers for therapy and to customize therapy based on an individual tumor genetic composition. This review summarized the current state of gene expression profile studies in esophageal cancer.

Prognostic significance of human epididymis protein 4 in epithelial ovarian cancer

OBJECTIVE

The purpose of this study was to evaluate the prognostic significance of serum human epididymis protein 4 (HE4) level in patients with epithelial ovarian cancer.

STUDY DESIGN

A total of 78 women diagnosed with a pelvic mass and operated on in our institute comprised our cohort. Forty-five of these were diagnosed with epithelial ovarian cancer and treated with debulking surgery, followed by taxane and platinum-based chemotherapy as clinically indicated. Preoperatively obtained serum samples were analyzed for levels of HE4 and CA125.

RESULTS

The elevated serum HE4 level was related to advanced stage and serous type of cancer. The median duration of the follow-up was 35.1 months. In advanced stage, the median progression-free survival (PFS) of patients with elevated serum HE4 levels was 20.1 months (95% CI, 15.7-24.6 months), whereas that of patients with normal serum HE4 level was 24.2 months (95% CI, 13.9-34.6 months) (p=0.029). Independent predictors for PFS in patients with advanced stage EOC included serum HE4 level (hazard ratio 2.24; 95% CI, 1.14 to 6.84; p=0.048).

CONCLUSIONS

Our results demonstrated that an elevated serum HE4 level was related to the advanced stage of epithelial ovarian cancer. An elevated serum level of HE4 is a poor prognostic factor for PFS in patients with epithelial ovarian cancer who were treated with debulking surgery and adjuvant taxane and platinum-based chemotherapy. The serum HE4 level is a promising indicator for the progression of cancer as well as a biomarker for the detection of epithelial ovarian cancer.

No benefit from combining HE4 and CA125 as ovarian tumor markers in a clinical setting

OBJECTIVE

About 70% of epithelial ovarian cancer patients (EOC) are diagnosed at advanced stage with a five-year survival rate of only 30%. Whilst CA125 detects peritoneally-spread disease, it has limited sensitivity for early cancers, many of which are potentially curable.

METHODS

We compared the new commercially available tumor marker HE4 with CA125 individually, in combination, within the risk of malignancy index (RMI) and the newly defined risk of malignancy algorithm (ROMA). Our prospectively-collected cohort of 160 patients consisted of healthy controls, benign diseases, and borderline tumors/adenocarcinomas of ovarian, tubal, peritoneal and endometrial origin. HE4 and CA125 were measured in serum using standardized ELISA.

RESULTS

Both markers showed similar diagnostic performance in the detection of EOC at clinically defined thresholds (CA125 35U/ml; HE4 70pM) but HE4 was not elevated in endometriosis. Comparison of non-malignant diagnoses (n=71) versus early stage ovarian and tubal cancers (n=19) revealed that HE4 and ROMA displayed the best diagnostic performance (AUC 0.86/0.87, specificity 85.9%/87.3% and sensitivity 78.9%/78.9%, respectively). Whilst RMICA125 detects peritoneal cancer better than all other models (AUC 0.99, specificity 97.2%, sensitivity 80.0%), there is no other detection benefit from RMI compared to HE4 alone or included in ROMA.

CONCLUSIONS

The major advantage of HE4 lies in its specificity and improved detection of borderline tumors and early stage ovarian and tubal cancers. HE4 is superior to CA125 with or without RMI and ROMA indices. However, we see no benefit from combining both markers in clinical practice.

fTwo novel biomarkers, mesothelin and HE4, for diagnosis of ovarian carcinoma

INTRODUCTION: There is a need to improve the diagnosis and prognosis of ovarian carcinoma, particularly the serous type of cancer. Mesothelin and HE4 are two novel biomarkers which are expressed in serous ovarian carcinoma and can be measured in serum and other body fluids, including urine, by using ELISA. The measurement of antibodies to these markers can provide additional useful information. AREAS COVERED: A literature search was performed to as recent as December 1 2010, using the Internet (e.g. PubMed) on articles concerning mesothelin and HE4 for the diagnosis of ovarian carcinoma. The authors also included up to date recent information from the research performed in their own laboratory. EXPERT OPINION: The combination of CA125 with HE4 facilitates the triaging of women with a pelvic mass and detects more stage I/II tumors than CA125, the present 'gold standard', when used alone. Assaying urine for HE4 or mesothelin may detect early ovarian carcinoma more often than assaying serum. Antibodies to mesothelin and HE4 are more frequent in women with ovarian carcinoma or with certain types of infertility than in controls. No presently available biomarker or multi-marker panel lends itself to screening large populations of symptomless women to make possible detection of high grade serous ovarian carcinoma at stage I or II. The authors anticipate, within the next 5 years, that a greater emphasis will be given to the fact that the different subtypes of ovarian carcinoma represent different types of disease. Each different type of disease will require a different diagnostic approach and more efforts will focus on high grade serous ovarian carcinoma for which the clinical need is the greatest.

Evaluation of the accuracy of serum human epididymis protein 4 in combination with CA125 for detecting ovarian cancer: a prospective case-control study in a Korean population

BACKGROUND

This study aimed to determine the serum concentrations of CA125 and human epididymis protein 4 (HE4) in patients with ovarian cancer, and to evaluate the sensitivity and specificity of these biomarkers for differentiating between patients with benign gynecological disease and those with ovarian cancer, when used alone and in combination in a Korean population.

METHODS

We consecutively recruited 159 women with an adnexal mass, including 78 women with ovarian cancer. A total of 224 healthy women served as controls. The serum concentrations of HE4 and CA125 were analyzed using immunochemiluminescence assays. The concentrations of the markers were compared among the different subgroups, and the diagnostic accuracy of each marker and the combination of the two markers was assessed by plotting receiver operating characteristic (ROC) curves. In addition, the Risk of Ovarian Malignancy Algorithm (ROMA) was utilized to categorize patients into low- and high-risk groups for epithelial ovarian cancer.

RESULTS

Serum HE4 and CA125 concentrations were significantly higher in the ovarian cancer patients compared with those seen in patients with benign disease or in the healthy controls (p<0.0001 in both). In patients with an adnexal mass, the area under the ROC curve was higher when the combination of the markers was used compared with use of CA125 only. Using ROMA, patients could be successfully classified into high- and low-risk group, with 87.5% sensitivity at a specificity of 93.8%.

CONCLUSIONS

These findings suggest that measuring serum HE4 concentrations along with CA125 concentrations may provide higher accuracy for detecting ovarian cancer.

Potential molecular targets in chemopreventative action of celecoxib: a proteomics analysis of J774.A1 macrophage-like cell line

The overexpression of cyclooxygenase-2 (COX-2) enzyme has been strongly contributed to tumorigenesis. The efficacy of celecoxib as a selective COX-2 inhibitor has been shown in many studies, but the underlying mechanism as a chemopreventative agent has not yet been well known. For better understanding the chemopreventative molecular mechanisms, we used a comparative proteomics analysis of lipopolysaccharide (LPS) treated and untreated J774.A1 macrophage-like cell lines before and after treatment with celecoxib. Our findings define the contribution of several interesting proteins, including ferritin heavy chain, glyoxalase-1, cofilin, vimentin, and galectin-1, which could extend our understanding of the chemopreventative effects of celecoxib and provide new valuable tools for further anticancer research.

Toxin-based therapeutic approaches

Protein toxins confer a defense against predation/grazing or a superior pathogenic competence upon the producing organism. Such toxins have been perfected through evolution in poisonous animals/plants and pathogenic bacteria. Over the past five decades, a lot of effort has been invested in studying their mechanism of action, the way they contribute to pathogenicity and in the development of antidotes that neutralize their action. In parallel, many research groups turned to explore the pharmaceutical potential of such toxins when they are used to efficiently impair essential cellular processes and/or damage the integrity of their target cells. The following review summarizes major advances in the field of toxin based therapeutics and offers a comprehensive description of the mode of action of each applied toxin.

Peri- and post-menopausal incidental adnexal masses and the risk of sporadic ovarian malignancy: new insights and clinical management

Adnexal masses are common among peri- and post-menopausal women. Although ovarian cancer is a significant cause of mortality in menopausal women, large population-based studies demonstrate that the majority of adnexal masses are benign. Despite this, the appearance of an adnexal mass is a concern for the patient and an insight exercise for physicians. In most cases, an adnexal enlargement is an incidental finding, generally corresponding to a benign cyst and easily diagnosed by conventional ultrasound. Exceptionally an ovarian tumour may be malignant and should be treated as early as possible. When conventional ultrasound renders complex morphology other diagnostic tools must be used such as: colour Doppler and functional tumour vessel properties, serum CA 125 levels, nuclear magnetic resonance imaging and in some cases laparoscopy. Several new tumour markers are being studied for clinical application, although there are presently no clear recommendations. Adnexal masses with benign morphological and functional properties must be periodically monitored as an alternative to surgery since malignant transformation is exceptional.

Detection of the HE4 protein in urine as a biomarker for ovarian neoplasms

The HE4 protein is overexpressed in ovarian carcinomas and can be detected in serum by an ELISA with sensitivity similar to CA125 and higher specificity for malignant disease. We now demonstrate that HE4 can also be detected in the urine at a specificity level of 94.4%, including 13/15 (86.6%) with stage I/II and 57/64 (89.0%) with stage III/IV disease and including 90.5% of patients with serous ovarian carcinoma. Assaying serum and urine from the same patients showed similar sensitivity. Our data indicate that measuring HE4 in urine may aid diagnosis and the monitoring of response to therapy.

Human epididymis protein 4 is a biomarker for transitional cell carcinoma in the urinary system

OBJECTIVE

To investigate human epididymis protein 4 (HE4) levels in transitional cell carcinoma (TCC) of the urinary system and its relationship with clinicopathological features.

METHODS

102 patients with TCC, 60 with benign urinary diseases, and 60 healthy controls were included in this study. The HE4 levels were used to analyze different clinicopathologic characteristics and changes between pre- and postsurgical operation.

RESULTS

The HE4 level was significantly increased in patients with TCC compared to patients with benign urinary diseases patients (P<0.01) and healthy controls (P<0.01), and the level of HE4 in patients with superficial TCC (Tis Ta T1) was significantly higher than that of the benign urogenital group (P<0.05)and healthy controls (P<0.05). There was a significant difference between HE4 levels in patients before and after operation (P<0.05). There was no difference between HE4 levels based on tumor recurrence, clinical TNM stage, lymph node metastasis, or pathological stage (P>0.05). The HE4 level was also different between patients with a single tumor versus patients with multiple tumors. The area under the curves of HE4 is 0.821. The sensitivity and specificity of HE4 at a cutoff value of 45.7 pM were 67.6 and 88.3%, respectively.

CONCLUSIONS

HE4 may be a screening tool for early diagnosis of TCC in the urinary system, and may become a prognostic marker for TCC in the urinary system.

Elevated MAL expression is accompanied by promoter hypomethylation and platinum resistance in epithelial ovarian cancer

We previously found that the gene encoding the Myelin and Lymphocyte protein, MAL, was among the most highly expressed genes in serous ovarian cancers from short-term survivors (<3 years) relative to those of long-term survivors (>7 years). In the present study, we have found that this difference in expression is partially attributable to differences in DNA methylation at a specific region within the MAL promoter CpG island. While MAL was largely unmethylated at the transcription start site (Region 1; -48 to +73 bp) in primary serous ovarian cancers, methylation of an upstream region (Region 2; -452 to -266 bp) was inversely correlated with MAL transcription in the primary cancers (R = -0.463) and ovarian cancer cell lines (R = -0.444). Following treatment of the OVCA432 cell line with 5-azacytidine, methylation of Region 2 decreased from 73.3% to 34.7% (p = 0.007) while Region 1 was unaffected. This was accompanied by a 10-fold increase in MAL expression. Since MAL transcripts are elevated in tumors from short-term survivors, all of whom were treated with platinum-based therapy, MAL may have a role in cisplatin response. We therefore determined the 50% growth inhibitory dose of cisplatin in 30 ovarian cancer cell lines and compared this to MAL expression. MAL transcript levels were higher in the resistant ovarian cell lines (p = 0.04). MAL methylation status may therefore serve as a marker of platinum sensitivity while MAL protein may be a target for development of novel therapies aimed at enhancing sensitivity to platinum-based drugs in ovarian cancer.

Targeting the epidermal growth factor receptor in epithelial ovarian cancer: current knowledge and future challenges

The epidermal growth factor receptor is overexpressed in up to 60% of ovarian epithelial malignancies. EGFR regulates complex cellular events due to the large number of ligands, dimerization partners, and diverse signaling pathways engaged. In ovarian cancer, EGFR activation is associated with increased malignant tumor phenotype and poorer patient outcome. However, unlike some other EGFR-positive solid tumors, treatment of ovarian tumors with anti-EGFR agents has induced minimal response. While the amount of information regarding EGFR-mediated signaling is considerable, current data provides little insight for the lack of efficacy of anti-EGFR agents in ovarian cancer. More comprehensive, systematic, and well-defined approaches are needed to dissect the roles that EGFR plays in the complex signaling processes in ovarian cancer as well as to identify biomarkers that can accurately predict sensitivity toward EGFR-targeted therapeutic agents. This new knowledge could facilitate the development of rational combinatorial therapies to sensitize tumor cells toward EGFR-targeted therapies.

Proteogenomic studies in epithelial ovarian cancer: established knowledge and future needs

There has been a concerted effort over the last decade to improve our understanding of the complex biology of ovarian cancer. A linear growth in published proteogenomic studies has addressed a variety of questions regarding its molecular pathogenesis. A number of genes have been identified by transcriptomic approaches, some of which are being investigated as putative tumor markers (HE4, OPN, Ep-CAM and Mesothelin), whilst others are potential targets for molecular therapeutic approaches (VEGF, IO4, EGFR, MUC1, CLDN4 and SLPI). Proteogenomics has the potential to further change our current characterization and treatment of ovarian cancer. Additional advances will depend on integrated study designs, interdisciplinary collaborations, use of robust high-throughput platforms, as well as uniform guidelines for bioinformatic analyses.