Current and future developments in screening for ovarian cancer

Meta-analysis based gene expression profiling reveals functional genes in ovarian cancer

Background: Ovarian cancer causes high mortality rate worldwide, and despite numerous attempts, the outcome for patients with ovarian cancer are still not well improved. Microarray-based gene expressional analysis provides with valuable information for discriminating functional genes in ovarian cancer development and progression. However, due to the differences in experimental design, the results varied significantly across individual datasets.

Methods: In the present study, the data of gene expression in ovarian cancer were downloaded from Gene Expression Omnibus (GEO) and 16 studies were included. A meta-analysis based gene expression analysis was performed to identify differentially expressed genes (DEGs). The most differentially expressed genes in our meta-analysis were selected for gene expression and gene function validation.

Results: A total of 972 DEGs with P-value < 0.001 were identified in ovarian cancer, including 541 up-regulated genes and 431 down-regulated genes, among which 92 additional DEGs were found as gained DEGs. Top five up- and down-regulated genes were selected for the validation of gene expression profiling. Among these genes, up-regulated CD24 molecule (CD24), SRY (sex determining region Y)-box transcription factor 17 (SOX17), WFDC2, epithelial cell adhesion molecule (EPCAM), innate immunity activator (INAVA), and down-regulated aldehyde oxidase 1 (AOX1) were revealed to be with consistent expressional patterns in clinical patient samples of ovarian cancer. Gene functional analysis demonstrated that up-regulated WFDC2 and INAVA promoted ovarian cancer cell migration, WFDC2 enhanced cell proliferation, while down-regulated AOX1 was functional in inducing cell apoptosis of ovarian cancer.

Conclusion: Our study shed light on the molecular mechanisms underlying the development of ovarian cancer, and facilitated the understanding of novel diagnostic and therapeutic targets in ovarian cancer.

Clinical significance of CD38 and CD101 expression in PD-1+CD8+ T cells in patients with epithelial ovarian cancer

Previous studies using mouse liver tumor models have indicated that coexpression of CD38 and CD101 in programmed cell death-1 (PD-1)⁺CD8⁺ T cells may reflect fixed dysregulation of CD8⁺ T cells and thus indicate a poor response to anti-PD-1 immunotherapy. However, whether CD38 and CD101 expression in PD-1⁺CD8⁺ T cells can predict the clinical status and efficacy of chemotherapy for various cancer types, including ovarian cancer (OC), remains unclear. In the present study, peripheral blood mononuclear cells (PBMCs) were obtained by Ficoll-Hypaque gradient centrifugation from 96 fresh samples from healthy adult volunteers and patients with epithelial OC, aged 55.21±9.91 years. Additionally, tumor-infiltrating lymphocytes (TILs) were separated using a combination of mechanical, chemical and enzymatic digestion from fresh surgically removed tumor tissues from 15 patients with epithelial OC. The expression of CD38 and CD101 in PD-1⁺CD8⁺ T cells or TILs was detected by flow cytometry or immunofluorescence (IF) staining, respectively. The association between the level of CD38/CD101 expression and clinicopathological parameters or postoperative chemotherapy in patients with OC was statistically analyzed. The levels of CD38/CD101-coexpressing PD-1⁺CD8⁺ T cells were significantly increased in PBMCs and TILs of patients with OC compared with those of healthy volunteers. The frequency of PD-1⁺CD38⁺CD101⁺CD8⁺ T cells among the total PD-1⁺CD8⁺ T cell subpopulation was negatively associated with clinical stage, lymph node metastasis and postoperative chemotherapy prognosis in patients with OC. Furthermore, IF staining confirmed colocalization of CD38 and CD101 on the majority of TILs in OC tissues. Thus, the present study suggests that coexpression of CD38 and CD101 in peripheral PD-1⁺CD8⁺ T cells and TILs may serve as a new indicator for diagnosis and treatment efficacy in patients with epithelial OC.

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.

The Establishment of an HE4-CLIA Method and the Combined Analysis of HE4 and CA125 in Ovarian Cancer

BACKGROUND

The human epididymal secretory protein 4 (HE4) is a novel, verified biomarker for the early diagnosis of ovarian cancer.

METHODS

Magnetic beads were coated with capture antibodies and were used with acridinium ester labeled detection antibodies in a sandwich-type immunoassay. The patient's HE4 serum levels were measured simultaneously with the chemiluminescence immunoassay (CLIA) kit we developed and electrochemiluminescence immunoassay (ECLIA) kit from Roche (Mannheim, Germany). CA125 was also detected by time-resolved fluoroimmunoassay. The diagnostic value was analyzed.

RESULTS

The assay demonstrated a linear range from 2.5 to 2,000 pmol/l, with an analytical sensitivity of 2.5 pmol/l. The reproducibility, recovery, and specificity of the immunoassay were demonstrated to be acceptable. Compared with the ECLIA kit from Roche in 124 serum samples (40 patients with ovarian cancer, 35 patients with benign gynecological diseases, and 49 health controls), there is a satisfied correlation coefficient of 0.875. The area under the receiver-operating curve (ROC-AUC) was 0.903 (95% CI was 0.839-0.966, P < 0.001) for HE4, 0.787 (95% CI was 0.694-0.879, P < 0.001) for CA125, and 0.914 (95% CI was 0.866-0.962, P < 0.001) for combined analysis of HE4 and CA125.

CONCLUSIONS

A quantitative method (HE4-CLIA) for detecting HE4 in serum was successfully established. Preliminary clinical sample analysis showed HE4-CLIA has a certain clinical value in the screening and diagnosis of ovarian cancer. Moreover, in distinguishing benign from malignant ovarian lesions, HE4 has higher demonstrated accuracy than CA125.

Detection of Human Epididymis Protein 4 (HE4) in Human Serum Samples Using a Specific Monoclonal Antibody-Based Sandwich Enzyme-Linked Immunosorbent Assay (ELISA)

BACKGROUND

The human epididymis protein 4 (HE4) may have high specificity in the detection of malignant diseases, making the development of an immunoassay for HE4 essential.

METHODS

In our study, a fusion gene was constructed encoded with the HE4 protein. This protein was then produced in the bacterial cells (Escherichia coli) and used to immunize mice in order to eventually generate hybridomas specific to HE4. The hybridoma supernatants were then screened, and four positive anti-HE4 cell lines were selected. These cell lines produce monoclonal antibodies against HE4 epitopes, as demonstrated in the Western blot as well as by direct enzyme-linked immunosorbent assay (ELISA). Using the developed antibodies, we successfully identified several good antibody pairs from the hybridomas, which allowed for the development of a sandwich ELISA to measure HE4 levels. By using the HE4 ELISA, we measured HE4 levels of 60 clinical human serum samples.

RESULTS

Compared with the Food and Drug Administration (FDA) approved kit (Roche), our results showed a strong positive correlation to those of the FDA-approved kit.

CONCLUSIONS

In summary, highly sensitive antibody pairs were screened against HE4, and a sandwich ELISA was developed as an accurate analytical tool for the detection of HE4 in human serum, which could be especially valuable for diagnosing ovarian carcinomas.

Use of CA125 and HE4 serum markers to predict ovarian cancer in elevated-risk women

BACKGROUND

Serum markers are used before pelvic imaging to improve specificity and positive predictive value (PPV) of ovarian cancer multimodal screening strategies.

METHODS

We conducted a randomized controlled pilot trial to estimate surgical PPV of a "2 of 3 tests positive" screening rule, and to compare use of HE4 as a first-line (Arm 1) versus a second-line (Arm 2) screen, in women at high and elevated risk for epithelial ovarian cancer (EOC) at five study sites. Semiannual screening was offered to 208 women ages 25 to 80 years with deleterious BRCA germline mutations and to 834 women ages 35 to 80 years with pedigrees suggesting inherited susceptibility. Annual screening was offered to 130 women ages 45 to 80 years (Risk Group 3) with epidemiologic and serum marker risk factors. Rising marker levels were identified using the parametric empirical Bayes algorithm.

RESULTS

Both strategies yielded surgical PPV above 25%. Protocol-indicated surgery was performed in 6 women, identifying two ovarian malignancies and yielding a surgical PPV in both arms combined of 33% (95% confidence interval: 4%-78%), 25% in Arm 1 and 50% in Arm 2. Surgical consultation was recommended for 37 women (26 in Arm 1 and 11 in Arm 2). On the basis of 12 women with at least 2 of 3 tests positive (CA125, HE4, or imaging), an intent-to-treat analysis yielded PPV of 14% in Arm 1 and 20% in Arm 2.

CONCLUSIONS

Positive screens were more frequent when HE4 was included in the primary screen.

IMPACT

HE4 may be useful as a confirmatory screen when rising CA125 is used alone as a primary screen.

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.

Effects of personal characteristics on serum CA125, mesothelin, and HE4 levels in healthy postmenopausal women at high-risk for ovarian cancer

OBJECTIVE

To evaluate if serum levels of candidate ovarian cancer biomarkers vary with individual characteristics of healthy women who are likely candidates for an ovarian cancer screening program.

METHODS

We analyzed serum CA125, mesothelin, and HE4 levels in a sample of 155 healthy postmenopausal women at increased risk for developing ovarian cancer based on personal and family cancer history. Information on reproductive, family and medical histories, lifestyle factors, and anthropometry was collected by self-report. Twenty-two factors were examined using univariate and multiple linear regression models for the three biomarker levels.

RESULTS

In the multivariate models, CA125 levels were significantly higher in women who had used talcum powder (P = 0.02) and were lower in women who were parous (P = 0.05). Mesothelin levels were significantly higher in older women (P = 0.01) and lower in heavier women (P = 0.03). HE4 levels were higher in older women (P = 0.001) and in women who began menstruating at an older age (P = 0.03).

CONCLUSIONS

CA125, mesothelin, and HE4 levels in healthy, postmenopausal women at increased risk for ovarian cancer are significantly associated with a few ovarian cancer risk factors. Since the effects of these personal characteristics on these serum markers are not large, their incorporation in screening algorithms may be unnecessary. This is true especially if a longitudinal algorithm is used because the marker level at the previous screen reflects personal characteristics such as age, body mass index, and age of menarche. Understanding the influence of personal factors on levels of novel early detection markers in healthy, unaffected women may have clinical utility in interpreting biomarker levels.

Evaluation of the novel serum markers B7-H4, Spondin 2, and DcR3 for diagnosis and early detection of ovarian cancer

OBJECTIVE

Early detection through regular screening could significantly reduce mortality from ovarian cancer. Advances in biomarkers and imaging continue to improve the sensitivity and specificity of cancer detection, but further improvements are still needed. In this study, we identified and evaluated three new serum biomarkers that may be used to improve detection of ovarian cancer.

METHODS

Through genomic analysis, we identified B7-H4, Spondin 2, and DcR3 as over-expressed genes in ovarian cancer tissues. Sensitive sandwich ELISAs were developed to analyze the level of these novel markers in 68 serum samples from patients with ovarian cancer (16 early stage, 52 late stage) and 108 control samples, and 20 healthy women from which two serum samples were collected 1 year apart. CA125 levels were measured in all samples.

RESULTS

Markers were evaluated for their ability to identify clinical disease. The three novel markers and CA125 were elevated in serum of ovarian cancer patients as compared to normal controls. B7-H4 showed the highest specificity, with the lowest frequency of elevation in all control groups. When all cases were compared against all controls, CA125, Spondin 2, B7-H4, and DcR3 showed areas under the ROC curve of 0.87, 0.78, 0.74, and 0.71, respectively. CA125 and B7-H4 showed the best diagnostic performance for early-stage, with AUCs of 0.90 and 0.80, respectively.

CONCLUSION

This study demonstrates that B7-H4, Spondin 2, and DcR3 are promising new ovarian cancer markers that may improve early detection of cancer when used in combination with traditional diagnostic tests.