Circulating Cell Free DNA as the Diagnostic Marker for Ovarian Cancer: A Systematic Review and Meta-Analysis

Clinical relevance of circulating tumor DNA in ovarian cancer: current issues and future opportunities

Ovarian cancer (OC) is the most lethal gynecologic malignancy worldwide. Due to the lack of effective screening and early detection strategies, many patients with OC are diagnosed with advanced disease, where treatment is rarely curative. Moreover, OC is characterized by high intratumor heterogeneity, which represents a major barrier to the development of effective treatments. Conventional tumor biopsy and blood-based biomarkers, such as cancer antigen 125 (CA125), have different limitations. Liquid biopsy has recently emerged as an attractive and promising area of investigation in oncology, due to its minimally invasive, safe, comprehensive, and real-time dynamic nature. Preliminary evidence suggests a potential role of liquid biopsy to refine OC management, by improving screening, early diagnosis, assessment of response to treatment, detection, and profiling of drug resistance. The current knowledge and the potential clinical value of liquid biopsy in OC is discussed in this review to provide an overview of the clinical settings in which its use might support and improve diagnosis and treatment.

Screening and identification of serum exosomal protein ZNF587B in liquid biopsy for ovarian cancer diagnosis

Addressing the critical challenge of early ovarian cancer (OC) detection, our study focuses on identifying novel biomarkers by analyzing preoperative peripheral blood exosomes from high-grade serous ovarian cancer (HGSC) patients and healthy controls. Utilizing high-performance liquid chromatography-mass spectrometry-based quantitative proteomics, we isolated and analyzed peripheral blood exosomes to identify differentially expressed proteins (DEPs). This comprehensive analysis, supported by gene ontology enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) database assessments, revealed 28 proteins with decreased abundance and 33 with increased abundance in HGSC patients compared to controls. Notably, Zinc Finger Protein 587B (ZNF587B) exhibited a significant reduction in abundance, confirmed by decreased mRNA and protein levels in HGSC and normal ovarian tissues, consistent with omes exosomal protein expression levels. Immunohistochemical staining further confirmed reduced ZNF587B protein levels in HGSC tissues. The significant correlation between ZNF587B expression levels and tumor stage underscores its potential as a valuable biomarker for early liquid biopsy screening of OC. Our findings suggest ZNF587B plays a crucial role in early HGSC detection, highlighting the importance of further research to validate its clinical utility and improve ovarian cancer patient outcomes.

Clinical utility and diagnostic value of tumor-educated platelets in lung cancer: a systematic review and meta-analysis

Background

The review addresses the knowledge gap concerning the diagnostic value and clinical utility of tumor-educated platelets (TEPs) in adult patients with lung cancer.

Methods

We searched twelve databases: PubMed, CENTRAL, EMBASE, CINAHL, MEDLINE, Scopus, ProQuest, MedRxiv, BioRxiv, SSRN, Clinicaltrials.gov, and CNKI up to 24 March 2023, to include any diagnostic study regarding TEPs and LC. TEPs diagnostic value was evaluated from pooled sensitivity and specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and the area under the curve (AUC). QUADAS 2 was used to assess the risk of bias. Heterogeneity analysis was assessed using the receiver operating characteristic (ROC) plane, Galbraith plot, bivariate boxplot, sensitivity analysis, and meta-regression. TEPs clinical utility was evaluated from Fagan's nomogram.

Results

44 reports from 10 studies, including 7,858 events and 6,632 controls, were analyzed. The pooled sensitivity, specificity, PLR, NLR, and DOR were 0.80 (95% CI 0.79-0.80), 0.69 (95% CI 0.69-0.70), 2.92 (95% CI 2.50-3.41), 0.26 (95% CI 0.21-0.32), and 12.1 (95% CI 8.61-16.76), respectively. In addition, the AUC of the Summary ROC curve was 0.85 (95% CI: 0.81-0.88). The overall risk of bias was low. Heterogeneity may result from cancer stage, cancer control, measuring equipment, and RNA types across studies. There was no apparent publication bias (p=0.29) with significant positive (79%) and negative (22%) post-test probability, according to Deeks funnel plot asymmetry test and Fagan's nomogram.

Conclusion

TEPs could be a moderately effective candidate biomarker for LC diagnosis.

Increased levels of NETosis biomarkers in high-grade serous ovarian cancer patients' biofluids: Potential role in disease diagnosis and management

Introduction

High-grade serous ovarian cancer (HGSOC) is the second most frequent gynecological malignancy but the most lethal, partially due to the spread of the disease through the peritoneal cavity. Recent evidence has shown that, apart from their role in immune defense through phagocytosis and degranulation, neutrophils are able to participate in cancer progression through the release of neutrophil extracellular traps (NETs) in a process called NETosis. NETs are composed of DNA, histones, calprotectin, myeloperoxidase (MPO) and elastase and the NETosis process has been proposed as a pre-requisite for the establishment of omental metastases in early stages of HGSOC. Nevertheless, its role in advanced stages remains to be elucidated. Therefore, our principal aim is to characterize a NETosis biomarker profile in biofluids from patients with advanced HGSOC and control women.

Methods

Specifically, five biomarkers of NETosis (cell-free DNA (cfDNA), nucleosomes, citrullinated histone 3 (citH3), calprotectin and MPO) were quantified in plasma and peritoneal fluid (PF) samples from patients (n=45) and control women (n=40).

Results

Our results showed that HGSOC patients presented a higher concentration of cfDNA, citH3 and calprotectin in plasma and of all five NETosis biomarkers in PF than control women. Moreover, these biomarkers showed a strong ability to differentiate the two clinical groups. Interestingly, neoadjuvant treatment (NT) seemed to reduce NETosis biomarkers mainly systemically (plasma) compared to the tumor environment (PF).

Discussion

In conclusion, NETosis biomarkers are present in the tumor environment of patients with advanced HGSOC, which might contribute to the progression of the disease. Besides, plasma cfDNA and calprotectin could represent minimally invasive surrogate biomarkers for HGSOC. Finally, NT modifies NETosis biomarkers levels mainly at the systemic level.

GD2 and GD3 gangliosides as diagnostic biomarkers for all stages and subtypes of epithelial ovarian cancer

Background

Ovarian cancer (OC) is the deadliest gynecological cancer, often diagnosed at advanced stages. A fast and accurate diagnostic method for early-stage OC is needed. The tumor marker gangliosides, GD2 and GD3, exhibit properties that make them ideal potential diagnostic biomarkers, but they have never before been quantified in OC. We investigated the diagnostic utility of GD2 and GD3 for diagnosis of all subtypes and stages of OC.

Methods

This retrospective study evaluated GD2 and GD3 expression in biobanked tissue and serum samples from patients with invasive epithelial OC, healthy donors, non-malignant gynecological conditions, and other cancers. GD2 and GD3 levels were evaluated in tissue samples by immunohistochemistry (n=299) and in two cohorts of serum samples by quantitative ELISA. A discovery cohort (n=379) showed feasibility of GD2 and GD3 quantitative ELISA for diagnosing OC, and a subsequent model cohort (n=200) was used to train and cross-validate a diagnostic model.

Results

GD2 and GD3 were expressed in tissues of all OC subtypes and FIGO stages but not in surrounding healthy tissue or other controls. In serum, GD2 and GD3 were elevated in patients with OC. A diagnostic model that included serum levels of GD2+GD3+age was superior to the standard of care (CA125, p<0.001) in diagnosing OC and early-stage (I/II) OC.

Conclusion

GD2 and GD3 expression was associated with high rates of selectivity and specificity for OC. A diagnostic model combining GD2 and GD3 quantification in serum had diagnostic power for all subtypes and all stages of OC, including early stage. Further research exploring the utility of GD2 and GD3 for diagnosis of OC is warranted.

Molecular Management of High-Grade Serous Ovarian Carcinoma

High-grade serous ovarian carcinoma (HGSOC) represents the most common form of epithelial ovarian carcinoma. The absence of specific symptoms leads to late-stage diagnosis, making HGSOC one of the gynecological cancers with the worst prognosis. The cellular origin of HGSOC and the role of reproductive hormones, genetic traits (such as alterations in P53 and DNA-repair mechanisms), chromosomal instability, or dysregulation of crucial signaling pathways have been considered when evaluating prognosis and response to therapy in HGSOC patients. However, the detection of HGSOC is still based on traditional methods such as carbohydrate antigen 125 (CA125) detection and ultrasound, and the combined use of these methods has yet to support significant reductions in overall mortality rates. The current paradigm for HGSOC management has moved towards early diagnosis via the non-invasive detection of molecular markers through liquid biopsies. This review presents an integrated view of the relevant cellular and molecular aspects involved in the etiopathogenesis of HGSOC and brings together studies that consider new horizons for the possible early detection of this gynecological cancer.

Integrated Microfluidic System for Cell-Free DNA Extraction from Plasma for Mutant Gene Detection and Quantification

Ovarian cancer (OvCa) is among the most severe gynecologic cancers, yet individuals may be asymptomatic during its early stages. Routine, early screening for genetic abnormalities associated with OvCa could improve prognoses, and this can be achieved by detecting mutant genes in cell-free DNA (cfDNA). Herein, we developed an integrated microfluidic chip (IMC) that could extract cfDNA from plasma and automatically detect and quantify mutations in the OvCa biomarker BRCA1. The cfDNA extraction module relied on a vortex-type micromixer to mix cfDNA with magnetic beads surface-coated with cfDNA probes and could isolate 76% of molecules from a 200 μL plasma sample in 45 min. The cfDNA quantification module, which comprised a micropump that evenly distributed 4.5 μL of purified cfDNA into the on-chip, allele-specific quantitative polymerase chain reaction (qPCR) zones, was capable of quantifying mutant genes within 90 min. By automating the cfDNA extraction and qPCR processes, this IMC could be used for clinical screening for OvCa-associated mutations.

The Prognostic Value of Circulating Tumor DNA in Ovarian Cancer: A Meta-Analysis

Background: Studies have shown that circulating tumor DNA (ctDNA) indicates a poor prognosis in ovarian cancer. In this study, meta-analysis was used to assess the relationship between ctDNA and the prognosis of patients with epithelial ovarian cancer. Methods: The clinical trials included in this study were obtained via a search of PubMed, the Cochrane Library, the Web of Science and Embase between the period of establishment and March 2020. We selected clinical studies using qualitative or quantitative ctDNA methods to analyse the prognosis of ovarian epithelial cancer, screened the studies according to the determined inclusion and exclusion criteria, and used the modified JADAD score scale and NOS scale for evaluation, with OS (overall survival) and PFS (progression-free survival) as end events. The Cochrane Evaluation Tool was used to evaluate the quality of the randomized controlled trials. Stata 15.0 software was used to combine the effect ratio (hazard ratio, HR) and its 95% confidence interval (CI). In addition, a source analysis of ctDNA specimens, an analysis of ctDNA detection methods and a subgroup and sensitivity analysis of FIGO staging were performed. Results: A total of 8 studies were included in this meta-analysis, and ctDNA was found to be an independent risk factor for patients with epithelial ovarian cancer (OS: HR = 2.36, 95% CI [1.76,3.17], P < .001; PFS: HR = 2.51, 95% CI [1.83,3.45]). Conclusions: The results of our analysis suggested that ctDNA is a potential biomarker that can be used to evaluate the prognosis of patients with ovarian cancer.

Future Screening Prospects for Ovarian Cancer

Simple Summary

Ovarian cancer (OC) has the highest mortality rate of all gynecological cancers. It is usually diagnosed in late stages (FIGO III-IV), and therefore, overall survival is very poor. If diagnosed at the early stages, ovarian cancer has a 90% five-year survival rate. Liquid biopsy has a good potential to improve early ovarian cancer detection and is discussed in this review.

Abstract

Current diagnostic tools used in clinical practice such as transvaginal ultrasound, CA 125, and HE4 are not sensitive and specific enough to diagnose OC in the early stages. A lack of early symptoms and an effective asymptomatic population screening strategy leads to a poor prognosis in OC. New diagnostic and screening methods are urgently needed for early OC diagnosis. Liquid biopsies have been considered as a new noninvasive and promising method, using plasma/serum, uterine lavage, and urine samples for early cancer detection. We analyzed recent studies on molecular biomarkers with specific emphasis on liquid biopsy methods and diagnostic efficacy for OC through the detection of circulating tumor cells, circulating cell-free DNA, small noncoding RNAs, and tumor-educated platelets.

Liquid biopsy as an option for predictive testing and prognosis in patients with lung cancer

BACKGROUND

The aim of this study was to investigate the clinical value of liquid biopsy as a primary source for variant analysis in lung cancer. In addition, we sought to characterize liquid biopsy variants and to correlate mutational load to clinical data.

METHODS

Circulating cell-free DNA was extracted from plasma from patients with lung cancer (n = 60) and controls with benign lung disease (n = 16). Variant analysis was performed using the AVENIO ctDNA Surveillance kit and the results were correlated to clinical and variant analysis data from tumor tissue or cytology retrieved from clinical routine diagnostics.

RESULTS

There were significantly more variants detected in lung cancer cases compared to controls (p = 0.011), but no difference between the histological subgroups of lung cancer was found (p = 0.465). Furthermore, significantly more variants were detected in patients with stage IIIb-IV disease compared to patients with stage I-IIIa (median 7 vs 4, p = 0.017). Plasma cfDNA mutational load was significantly associated with overall survival (p = 0.010). The association persisted when adjusted for stage and ECOG performance status (HR: 3.64, 95% CI 1.37-9.67, p = 0.009). Agreement between tumor and plasma samples significantly differed with stage; patients with stage IIIb-IV disease showed agreement in 88.2% of the cases with clinically relevant variants, compared to zero cases in stage I-IIIa (p = 0.004). Furthermore, one variant in EGFR, two in KRAS, and one in BRAF were detected in plasma but not in tumor samples.

CONCLUSION

This study concludes that in the vast majority of advanced NSCLC patients a reliable variant analysis can be performed using liquid biopsy from plasma. Furthermore, we found that the number of variants in plasma is associated with prognosis, possibly indicating a strategy for closer follow up on this crucial patient group.

ESGO/ISUOG/IOTA/ESGE Consensus Statement on preoperative diagnosis of ovarian tumors

The European Society of Gynaecological Oncology (ESGO), the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG), the International Ovarian Tumour Analysis (IOTA) group and the European Society for Gynaecological Endoscopy (ESGE) jointly developed clinically relevant and evidence-based statements on the preoperative diagnosis of ovarian tumors, including imaging techniques, biomarkers and prediction models. ESGO/ISUOG/IOTA/ESGE nominated a multidisciplinary international group, including expert practising clinicians and researchers who have demonstrated leadership and expertise in the preoperative diagnosis of ovarian tumors and management of patients with ovarian cancer (19 experts across Europe). A patient representative was also included in the group. To ensure that the statements were evidence-based, the current literature was reviewed and critically appraised. Preliminary statements were drafted based on the review of the relevant literature. During a conference call, the whole group discussed each preliminary statement and a first round of voting was carried out. Statements were removed when consensus among group members was not obtained. The voters had the opportunity to provide comments/suggestions with their votes. The statements were then revised accordingly. Another round of voting was carried out according to the same rules to allow the whole group to evaluate the revised version of the statements. The group achieved consensus on 18 statements. This Consensus Statement presents these ESGO/ISUOG/IOTA/ESGE statements on the preoperative diagnosis of ovarian tumors and the assessment of carcinomatosis, together with a summary of the evidence supporting each statement.

ESGO/ISUOG/IOTA/ESGE Consensus Statement on preoperative diagnosis of ovarian tumours

The European Society of Gynaecological Oncology (ESGO), the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG), the International Ovarian Tumour Analysis (IOTA) group and the European Society for Gynaecological Endoscopy (ESGE) jointly developed clinically relevant and evidence-based statements on the preoperative diagnosis of ovarian tumours, including imaging techniques, biomarkers and prediction models.

ESGO/ISUOG/IOTA/ESGE nominated a multidisciplinary international group, including expert practising clinicians and researchers who have demonstrated leadership and expertise in the preoperative diagnosis of ovarian tumours and management of patients with ovarian cancer (19 experts across Europe). A patient representative was also included in the group. To ensure that the statements were evidence-based, the current literature was reviewed and critically appraised.

Preliminary statements were drafted based on the review of the relevant literature. During a conference call, the whole group discussed each preliminary statement and a first round of voting was carried out. Statements were removed when a consensus among group members was not obtained. The voters had the opportunity to provide comments/suggestions with their votes. The statements were then revised accordingly. Another round of voting was carried out according to the same rules to allow the whole group to evaluate the revised version of the statements. The group achieved consensus on 18 statements.

This Consensus Statement presents these ESGO/ISUOG/IOTA/ESGE statements on the preoperative diagnosis of ovarian tumours and the assessment of carcinomatosis, together with a summary of the evidence supporting each statement.

ESGO/ISUOG/IOTA/ESGE Consensus Statement on pre-operative diagnosis of ovarian tumors

The European Society of Gynaecological Oncology (ESGO), the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG), the International Ovarian Tumour Analysis (IOTA) group, and the European Society for Gynaecological Endoscopy (ESGE) jointly developed clinically relevant and evidence-based statements on the pre-operative diagnosis of ovarian tumors, including imaging techniques, biomarkers, and prediction models. ESGO/ISUOG/IOTA/ESGE nominated a multidisciplinary international group, including expert practising clinicians and researchers who have demonstrated leadership and expertise in the pre-operative diagnosis of ovarian tumors and management of patients with ovarian cancer (19 experts across Europe). A patient representative was also included in the group. To ensure that the statements were evidence-based, the current literature was reviewed and critically appraised. Preliminary statements were drafted based on the review of the relevant literature. During a conference call, the whole group discussed each preliminary statement and a first round of voting was carried out. Statements were removed when a consensus among group members was not obtained. The voters had the opportunity to provide comments/suggestions with their votes. The statements were then revised accordingly. Another round of voting was carried out according to the same rules to allow the whole group to evaluate the revised version of the statements. The group achieved consensus on 18 statements. This Consensus Statement presents these ESGO/ISUOG/IOTA/ESGE statements on the pre-operative diagnosis of ovarian tumors and the assessment of carcinomatosis, together with a summary of the evidence supporting each statement.

In Silico screening of circulating tumor DNA, circulating microRNAs, and long non-coding RNAs as diagnostic molecular biomarkers in ovarian cancer: A comprehensive meta-analysis

BACKGROUND

Ovarian cancer (OC) is a leading cause of death in gynecological malignancies worldwide. Multitudinous studies have suggested the potential of circulating tumor DNA (ctDNA), circulating microRNAs (miRNAs), and long non-coding RNAs (lncRNAs) as novel diagnostic molecular biomarkers for OC. Here, we include three updated meta-analysis methods using different molecular biomarkers to evaluate their discriminative value in OC diagnosis.

METHODS

We conducted three meta-analyses after searching different databases, and 23 eligible articles, including 8 concerning ctDNA, 11 concerning miRNAs, and 4 concerning lncRNAs, were found. Further, we pooled data concerning the sensitivity, specificity, and other indicators of accuracy for ctDNA/miRNAs/lncRNAs in the diagnosis of OC. The heterogeneity was further explored by meta-regressions and subgroup analyses, and Deeks' funnel plots were used to measure the publication bias of these three meta-analyses.

RESULTS

In all, this meta-analysis included 1732 OC patients and 3958 controls. The sensitivity of ctDNA for OC diagnosis was superior to that of lncRNA and miRNA (84% vs. 81% vs. 78%). Moreover, the specificity and area under the receiver-operating characteristic (ROC) curve (AUC) of ctDNA were 91% and 94%, which were significantly higher than those of miRNA and lncRNAs (78% and 85%; 78% and 86%, respectively). No significant difference was observed among the two meta-analyses of ctDNA and lncRNA (P > 0.05) with regard to publication bias, while the meta-analysis of miRNA observed a significantly small publication bias (P < 0.05).

CONCLUSION

ctDNA/miRNAs/lncRNAs may be promising molecular biomarkers for OC diagnosis. Further large-scale studies are needed to verify the potential applicability of ctDNA/miRNAs/lncRNAs molecular signatures alone or in combination as diagnostic molecular biomarkers for OC.

Can Circulating Cell-Free DNA or Circulating Tumor DNA Be a Promising Marker in Ovarian Cancer?

In recent years, the studies on ovarian cancer have made great progress, but the morbidity and mortality of patients with ovarian cancer are still very high. Due to the lack of effective early screening and detecting tools, 70% of ovarian cancer patients are diagnosed at an advanced stage. The overall survival rate of ovarian cancer patients treated with surgical combined with chemotherapy has not been significantly improved, and they usually relapse or resist chemotherapy. Therefore, a novel tumor marker is beneficial for the diagnosis and prognosis of patients with ovarian cancer. As the index of "liquid biopsy," circulating cell-free DNA/circulating tumor DNA (cfDNA/ctDNA) has attracted a lot of attention. It has more remarkable advantages than traditional methods and gives a wide range of clinical applications in kinds of solid tumors. This review attempts to illuminate the important value of cfDNA/ctDNA in ovarian cancer, including diagnosis, monitoring, and prognosis. Meanwhile, we will present future directions and challenges for detection of cfDNA/ctDNA.

When Tissue is an Issue the Liquid Biopsy is Nonissue: A Review

Precision medicine has impacted the field of medical oncology by introducing personalized therapies, improving all measurable outcomes. This field, in turn, has expanded to obtaining and analyzing a vast and ever-increasing amount of genomic information. One technique currently applied is the liquid biopsy, which consists of detecting and isolating DNA and exosomes in cancer patients. Newly developed techniques have made it possible to use the liquid biopsy in a wide range of settings. However, challenges regarding the validation of its clinical utility exist because of a lack of standardization across different techniques and tumor types, confounder genomic information, lack of appropriate clinical trial designs, and a non-measured, and therefore not estimated, economic impact on population health. Nowadays, liquid biopsy is not routinely used, but ongoing research is increasing its popularity, and a new era in oncology is developing. Therefore, it is essential to have an in-depth understanding of the liquid biopsy technique. In this review, we summarize the leading techniques and liquid biopsy applications in cancer.

Circulating tumor DNA analysis for tumor diagnosis

Tumor is a kind of abnormal organism generated by the proliferation and differentiation of cells in the body under the action of various initiating and promoting factors, which seriously threatens human life and health. Tumorigenesis is a gradual process that involves multistage reactions and the accumulation of mutations. Gene mutation usually occurs during tumorigenesis, and can be used for tumor diagnosis. Early diagnosis is the most effective way to improve the cure rate and reduce the mortality rate. Among the peripheral blood circulating tumor DNA (ctDNA), gene mutation in keeping with tumor cells can be detected, which can potentially replace tumor tissue section for early diagnosis. It has been considered as a liquid biopsy marker with good clinical application prospect. However, the high fragmentation and low concentration of ctDNA in blood result in the difficulty of tumor stage determination. Therefore, high sensitive and specific mutation detection methods have been developed to detect trace mutant ctDNA. At present, the approaches include digital PCR (dPCR), Bead, Emulsion, Amplification and Magnetic (BEAMing), Next Generation Sequencing (NGS), Amplification Refractory Mutation System (ARMS), etc. In this paper, the principle, characteristics, latest progress and application prospects of these methods are reviewed, which will facilitate researchers to choose appropriate ctDNA detection approaches.

Circulating Cell-Free DNA Methylation Profiles in the Early Detection of Ovarian Cancer: A Scoping Review of the Literature

Simple Summary

There are limited non-invasive methods for detecting epithelial ovarian cancer despite early detection and treatment dramatically increasing survival. As alterations in serum or plasma cell-free (cf)DNA methylation occur early in cancer development, they are promising biomarkers for ovarian cancer. Our literature review includes 18 studies depicting a wide array of gene targets and techniques. The data suggest a good performance of these cfDNA methylation tests, with accuracies up to 91% in detecting ovarian cancer in serum or plasma.

Abstract

Epithelial ovarian cancer is the most lethal gynecologic malignancy and has few reliable non-invasive tests for early detection or diagnosis. Recent advances in genomic techniques have bolstered the utility of cell-free DNA (cfDNA) evaluation from peripheral blood as a viable cancer biomarker. For multiple reasons, comparing alterations in DNA methylation is particularly advantageous over other molecular assays. We performed a literature review for studies exploring cfDNA methylation in serum and plasma for the early diagnosis of ovarian cancer. The data suggest that serum/plasma cfDNA methylation tests have strong diagnostic accuracies for ovarian cancer (median 85%, range 40–91%). Moreover, there is improved diagnostic performance if multiple genes are used and if the assays are designed to compare detection of ovarian cancer with benign pelvic masses. We further highlight the vast array of possible gene targets and techniques, and a need to include more earlier-stage ovarian cancer samples in test development. Overall, we show the promise of cfDNA methylation analysis in the development of a viable diagnostic biomarker for ovarian cancer.

Circulating cell-free DNA (cfDNA) levels in BRCA1 and BRCA2 mutation carriers: A preliminary study

BACKGROUND

Female carriers of BRCA1 or BRCA2 germline mutations are at a substantially increased risk for developing breast and ovarian cancer. The lack of effective early detection schemes for ovarian cancer, mandate surgical removal of adnexa at age 35-40 years in these high-risk women. The role of circulating cell-free DNA (cfDNA) levels as a marker for early detection in high-risk women has rarely been reported.

OBJECTIVE

To quantify cfDNA levels in BRCA1BRCA2 carriers.

METHODS

Serum cfDNA levels, measured by direct fluorometric assay in cancer-free female BRCA1BRCA2 mutation carriers were compared with cancer-free controls recruited from among women undergoing breast biopsy or routine colonoscopy.

RESULTS

Overall, 10 BRCA1 (185delAG) and 10 BRCA2 (6174delT) mutation carriers, 20 breast biopsy controls, and 20 colonoscopy controls participated. cfDNA levels [Median (95% CI)], were 472 (317-589) ng/ml and 525 (339-621) ng/ml in breast biopsy and colonoscopy controls, respectively. Median levels of cfDNA in BRCA1 and BRCA2 mutation carriers combined were 921 (835-1087) ng/ml, significantly higher than in both controls (P< 0.0001).

CONCLUSIONS

cfDNA levels are significantly higher in BRCA1 and BRCA2 mutation carriers compared with non-carriers. This finding, if validated, may facilitate development of early detection breast/ovarian cancer biomarker in high-risk women.

Evaluation of circulating cell-free nuclear and mitochondrial DNA levels in Syrian patients with breast tumor

In the last decade, the roles of circulating cell free nuclear (ccfn) and ccf mitochondrial (ccfmt) DNA as potential noninvasive biomarkers have been demonstrated in numerous different types of disease, including cancer. However, the results remain controversial. The present study aimed to investigate the roles of ccfnDNA and ccfmtDNA levels in the plasma of patients with breast cancer. A total of 84 Syrian female subjects were included in the study, who were divided into 3 groups: i) Malignant disease group (n=33); ii) benign disease group (n=26); and iii) healthy control group (n=25). CcfnDNA and ccfmtDNA were determined using real-time quantitative PCR and the reactions were followed by melting curve analysis. The results indicated no significant differences in the plasma levels of ccfnDNA, ccfmtDNA or the ratio of ccfmtDNA/ccfnDNA between the study groups. Of note, a positive correlation was observed between the ccfmtDNA/ccfnDNA ratio and age in the control group (P=0.012; r=0.505). In addition, a positive correlation was identified between ccfnDNA levels and the estrogen receptor status (P=0.045; r=0.416), while a negative correlation between ccfmtDNA/ccfnDNA ratio and the progesterone receptor status was obtained (P=0.045; r=-0.448. Aging and the role of hormones in the cells may be responsible for these results. In the future, the present study should be followed up with mutation detection analyses and large-scale studies.

Potential value of circulating tumor DNA in gynecological tumors

Though the survival of patients with gynecological tumors has been significantly prolonged by radiotherapy, chemotherapy, targeted therapy and other treatments, the way to improve the patients' life quality still needs investigation. Circulating tumor DNA (ctDNA), which contains tumor genetic information, has the potential in early diagnosis of malignancies due to its high consistency with tumor tissues. Using the key words including "digital PCR", "ctDNA", "technology of digital PCR", and "detection method", "gynecological tumor", we retrieved the original articles and reviews in PubMed and WEB OF SCI database published before May 10, 2019 and performed a thorough review of them. The analysis of ctDNA could provide a comprehensive description of tumor genome, overcome the heterogeneity of tissue biopsy, and supplement the missing mutations in tissue samples. Furthermore, ctDNA could be used as a target of liquid biopsy. Our study also showed that digital PCR technology has a good potential to detect ctDNA in gynecological tumors.

Liquid biopsy in ovarian cancer

Ovarian cancer is typically diagnosed at an advanced stage and poses a significant challenge to treatment and recovery. Relapsed ovarian cancer and chemoresistance of ovarian tumor cells are other clinical challenges. Liquid biopsy is an essential non-invasive diagnostic test that evaluates circulating tumor cells and tumor DNA, as well as other blood markers that may be useful in guiding precision medicine. Although liquid biopsy is not a routinely used diagnostic test, the potential applications in the diagnosis and prognosis in ovarian cancer are rapidly growing. This review explores recent studies examining the clinical potential of circulating tumor cells, cell-free microRNA, exosomes, tumor DNA, and other analytes as a source of liquid biopsy biomarkers in ovarian cancer diagnosis, prognosis and response to treatment.

Increased circulating tumor DNA as a noninvasive biomarker of early treatment response in patients with metastatic ovarian carcinoma: A pilot study

Detection of circulating tumor DNA is a new noninvasive technique with potential roles in diagnostic, follow-up, and prognostic evaluation of patients with many types of solid tumors. We aimed to evaluate the role of circulating tumor DNA in the setting of metastatic ovarian carcinoma. A prospective cohort of patients with metastatic ovarian cancer who were referred to systemic therapy was enrolled. Blood samples were collected before the start of treatment and monthly thereafter for 6 months. Circulating tumor DNA was quantified by real-time quantitative reverse transcription polymerase chain reaction of different lengths of Arthrobacter luteus elements as described by Umetani et al. A total of 11 patients were included, 2 for primary disease and 9 for recurrent disease. After the first cycle of chemotherapy, patients whose circulating tumor DNA levels increased from baseline were more likely to respond to chemotherapy than those whose circulating tumor DNA levels did not increase (p = 0.035). Furthermore, patients whose circulating tumor DNA levels rose after the first cycle of chemotherapy also had improved disease-free survival compared to those whose circulating tumor DNA levels did not increase (p = 0.0074). We conclude that the increase in circulating tumor DNA values collected in peripheral blood after the first cycle of systemic treatment in patients with advanced ovarian cancer is associated with an early response to systemic treatment and correlates with superior disease-free survival in this population. Circulating tumor DNA might be a specific, noninvasive, and cost-effective new biomarker of early response to systemic treatment in these patients.

Circulating HPV cDNA in the blood as a reliable biomarker for cervical cancer: A meta-analysis

The applications of liquid biopsy have attracted much attention in biomedical research in recent years. Circulating cell-free DNA (cfDNA) in the serum may serve as a unique tumor marker in various types of cancer. Circulating tumor DNA (ctDNA) is a type of serum cfDNA found in patients with cancer and contains abundant information regarding tumor characteristics, highlighting its potential diagnostic value in the clinical setting. However, the diagnostic value of cfDNA as a biomarker, especially circulating HPV DNA (HPV cDNA) in cervical cancer remains unclear. Here, we performed a meta-analysis to evaluate the applications of HPV cDNA as a biomarker in cervical cancer. A systematic literature search was performed using PubMed, Embase, and WANFANG MED ONLINE databases up to March 18, 2019. All literature was analyzed using Meta Disc 1.4 and STATA 14.0 software. Diagnostic measures of accuracy of HPV cDNA in cervical cancer were pooled and investigated. Fifteen studies comprising 684 patients with cervical cancer met our inclusion criteria and were subjected to analysis. The pooled sensitivity and specificity were 0.27 (95% confidence interval [CI], 0.24–0.30) and 0.94(95% CI, 0.92–0.96), respectively. The pooled positive likelihood ratio and negative likelihood ratio were 6.85 (95% CI, 3.09–15.21) and 0.60 (95% CI, 0.46–0.78), respectively. The diagnostic odds ratio was 15.25 (95% CI, 5.42–42.94), and the area under the summary receiver operating characteristic curve was 0.94 (95% CI, 0.89–0.99). There was no significant publication bias observed. In the included studies, HPV cDNA showed clear diagnostic value for diagnosing and monitoring cervical cancer. Our meta-analysis suggested that detection of HPV cDNA in patients with cervical cancer could be used as a noninvasive early dynamic biomarker of tumors, with high specificity and moderate sensitivity. Further large-scale prospective studies are required to validate the factors that may influence the accuracy of cervical cancer diagnosis and monitoring.

Changes in the gene mutation profiles of circulating tumor DNA detected using CAPP-Seq in neoadjuvant chemotherapy-treated advanced ovarian cancer

Cancer Personalized Profiling by deep Sequencing (CAPP-Seq) is a novel ultrasensitive next-generation sequencing-based approach that is used to detect circulating tumor DNA (ctDNA). The aim of the present study was to compare the gene mutation profiles and blood tumor mutation burden (bTMB) measured between pre- and post-neoadjuvant chemotherapy (NAC), utilizing CAPP-seq for plasma ctDNA in patients with advanced ovarian cancer. The current study included 10 patients (6 NAC-sensitive and 4 NAC-resistant) clinically diagnosed as having stage III or IV ovarian cancer and were administered NAC between May 2017 and February 2019. The plasma ctDNA samples were collected at pre- and post-NAC, and comprehensive gene mutation analysis was performed using CAPP-seq. In 5 out of 6 NAC-sensitive cases, the variant allele frequency (VAF) of non-synonymous somatic mutations decreased following NAC. In 2 out of the 4 NAC-resistant cases, the VAF of non-synonymous somatic mutations increased, and new somatic mutations emerged following NAC. In regard to TP53 mutation, the rate of TP53 mutation in the NAC-resistant cases was significantly higher compared with NAC-sensitive cases. Finally, the bTMB decreased significantly after NAC treatment in the NAC-sensitive cases, even though there were no significant differences in the pretreatment bTMB levels between the NAC-sensitive and NAC-resistant cases. These results indicated that gene mutation can be profiled and monitored using liquid biopsy-based CAPP-Seq in patients with advanced ovarian cancer with NAC treatment, and TP53 mutation in the ctDNA and bTMB may be novel biomarkers that can be used for patient monitoring during NAC treatment.

Ovarian cancer detection by DNA methylation in cervical scrapings

Background

Ovarian cancer (OC) is the most lethal gynecological cancer, worldwide, largely due to its vague and nonspecific early stage symptoms, resulting in most tumors being found at advanced stages. Moreover, due to its relative rarity, there are currently no satisfactory methods for OC screening, which remains a controversial and cost-prohibitive issue. Here, we demonstrate that Papanicolaou test (Pap test) cervical scrapings, instead of blood, can reveal genetic/epigenetic information for OC detection, using specific and sensitive DNA methylation biomarkers.

Results

We analyzed the methylomes of tissues (50 OC tissues versus 6 normal ovarian epithelia) and cervical scrapings (5 OC patients versus 10 normal controls), and integrated public methylomic datasets, including 79 OC tissues and 6 normal tubal epithelia. Differentially methylated genes were further classified by unsupervised hierarchical clustering, and each candidate biomarker gene was verified in both OC tissues and cervical scrapings by either quantitative methylation-specific polymerase chain reaction (qMSP) or bisulfite pyrosequencing. A risk-score by logistic regression was generated for clinical application.

One hundred fifty-one genes were classified into four clusters, and nine candidate hypermethylated genes from these four clusters were selected. Among these, four genes fulfilled our selection criteria and were validated in training and testing set, respectively. The OC detection accuracy was demonstrated by area under the receiver operating characteristic curves (AUCs) in 0.80–0.83 of AMPD3, 0.79–0.85 of AOX1, 0.78–0.88 of NRN1, and 0.82–0.85 of TBX15. From this, we found OC-risk score, equation generated by logistic regression in training set and validated an OC-associated panel comprising AMPD3, NRN1, and TBX15, reaching a sensitivity of 81%, specificity of 84%, and OC detection accuracy of 0.91 (95% CI, 0.82–1) in testing set.

Conclusions

Ovarian cancer detection from cervical scrapings is feasible, using particularly promising epigenetic biomarkers such as AMPD3/NRN1/TBX15. Further validation is warranted.

Aberrant Methylation Status of Tumour Suppressor Genes in Ovarian Cancer Tissue and Paired Plasma Samples

Ovarian cancer is a highly heterogeneous disease and its formation is affected by many epidemiological factors. It has typical lack of early signs and symptoms, and almost 70% of ovarian cancers are diagnosed in advanced stages. Robust, early and non-invasive ovarian cancer diagnosis will certainly be beneficial. Herein we analysed the regulatory sequence methylation profiles of the RASSF1, PTEN, CDH1 and PAX1 tumour suppressor genes by pyrosequencing in healthy, benign and malignant ovarian tissues, and corresponding plasma samples. We recorded statistically significant higher methylation levels (p < 0.05) in the CDH1 and PAX1 genes in malignant tissues than in controls (39.06 ± 18.78 versus 24.22 ± 6.93; 13.55 ± 10.65 versus 5.73 ± 2.19). Higher values in the CDH1 gene were also found in plasma samples (22.25 ± 14.13 versus 46.42 ± 20.91). A similar methylation pattern with positive correlation between plasma and benign lesions was noted in the CDH1 gene (r = 0.886, p = 0.019) and malignant lesions in the PAX1 gene (r = 0.771, p < 0.001). The random forest algorithm combining methylation indices of all four genes and age determined 0.932 AUC (area under the receiver operating characteristic (ROC) curve) prediction power in the model classifying malignant lesions and controls. Our study results indicate the effects of methylation changes in ovarian cancer development and suggest that the CDH1 gene is a potential candidate for non-invasive diagnosis of ovarian cancer.

Liquid biopsy in ovarian cancer: recent advances in circulating extracellular vesicle detection for early diagnosis and monitoring progression

The current biomarkers available in the clinic are not enough for early diagnosis or for monitoring disease progression of ovarian cancer. Liquid biopsy is a minimally invasive test and has the advantage of early diagnosis and real-time monitoring of treatment response. Although significant progress has been made in the usage of circulating tumor cells and cell-free DNA for ovarian cancer diagnosis, their potential for early detection or monitoring progression remains elusive. Extracellular vesicles (EVs) are a heterogeneous group of lipid membranous particles released from almost all cell types. EVs contain proteins, mRNA, DNA fragments, non-coding RNAs, and lipids and play a critical role in intercellular communication. Emerging evidence suggests that EVs have crucial roles in cancer development and metastasis, thus holding promise for liquid biopsy-based biomarker discovery for ovarian cancer diagnosis. In this review, we discuss the advantages of EV-based liquid biopsy, summarize the protein biomarkers identified from EVs in ovarian cancer, and highlight the utility of new technologies recently developed for EV detection with an emphasis on their use for diagnosing ovarian cancer, monitoring cancer progression, and developing personalized medicine.

Detection of cell-free, exosomal and whole blood mitochondrial DNA copy number in plasma or whole blood of patients with serous epithelial ovarian cancer

Ovarian tumor is one of the leading causes of cancer among women. Patients are diagnosed at an advanced stage, usually. There is a need for new specific and sensitive biomarkers. Mitochondrial DNA copy number change was observed in various cancers. Our aim was to detect mitochondrial DNA copy number in whole blood (wb-mtDNA) and in plasma (cell-free and exosome encapsulated mtDNA) in patients with serous epithelial ovarian tumor. DNA was isolated from EDTA blood and plasma obtained from 24 patients and 24 healthy controls. Exosomes were isolated from cell-free plasma, and exosome encapsulated DNA (exoDNA) was extracted. Quantitative-real-time PCR was performed with Human Mitochondrial DNA (mtDNA) Monitoring Primer Set. Kruskall‑Wallis and Mann‑Whitney U test were used for data analysis. Wb-mtDNA copy number was significantly different among healthy controls and patients in multiple comparison (p = 0.0090 considering FIGO stage independently, and p = 0.0048 considering early- and late-stage cancers). There was a significant decrease among early-stage, all advanced stage and all cancer patients (FIGO I: 32.5 ± 8.3, p = 0.0061; FIGO III + IV: 37.2 ± 13.7 p = 0.0139; FIGO I + III + IV: 35.6 ± 12.2, p = 0.0017) or FIGO III patients alone (32.8 ± 5.6, p = 0.00089) compared to healthy controls. We found significant increase in copy number in exosomal mtDNA in cancer patients (236.0 ± 499.0, p = 0.0155), advanced-stage cancer patients (333.0 ± 575.0, p = 0.0095), of FIGO III (362.0 ± 609.2, p = 0.0494), and FIGO IV (304.0 ± 585.0, p = 0.0393) patients alone but not in samples of FIGO I patients (10.0 ± 3.5, p = 0.3907). In multiple comparison the increase was significant considering early- and late-stage cancers (p = 0.0253). Cell-free mtDNA copy numbers were not increased significantly. We found the highest copy number of mtDNA in exosomes, followed by plasma and peripheral blood in late-stage cancer patients. We observed significant difference in wb-mtDNA copy number between healthy controls and both early- and late-stage cancer patients.

Multiple biomarker algorithms to predict epithelial ovarian cancer in women with a pelvic mass: Can additional makers improve performance?

INTRODUCTION

Management of a woman with a pelvic mass is complicated by difficulty in discriminating malignant from benign disease. Many serum biomarkers have been examined to determine their sensitivity for detecting malignancy. This study was designed to evaluate if the addition of biomarkers to HE4 and CA125, as used in the Risk of Malignancy Algorithm (ROMA), can improve the detection of EOC.

METHODS

This was an IRB approved, prospective clinical trial examining serum obtained from women diagnosed with a pelvic mass who subsequently underwent surgery. Serum biomarker levels for CA125, HE4, YKL-40, transthyretin, ApoA1, Beta-2-microglobulin, transferrin, and LPA were measured. Logistic regression analysis was performed for various marker combinations, ROC curves were generated, and the area under the curves (AUCs) were determined.

RESULTS

A total of 184 patients met inclusion criteria with a median age of 56 years (Range 20-91). Final pathology revealed there were 103 (56.0%) benign tumors, 4 (2.2%) LMP tumors, 61 EOC (33.1%), 2 (1.1%) non-EOC ovarian cancers, 6 (3.3%) gynecologic cancers with metastasis to the ovary and 8 (4.3%) non-gynecologic cancers with metastasis to the ovary. The combination of HE4 and CA125 (i.e. ROMA) achieved an AUC of 91.2% (95% CI: 86.0-96.4) for the detection of EOC vs benign disease. The combination of CA125, HE4, YKL-40, transthyretin, ApoA1, Beta 2 microglobulin, transferrin, LPA and menopausal status achieved the highest AUC of 94.6% (95% CI: 90.1-99.2) but this combination was not significantly better than the HE4 and CA125 combination alone (p = 0.078).

CONCLUSIONS

The addition of select further serum biomarkers to HE4 and CA125 does not add to the performance of the dual marker combination for the detection of ovarian cancer.

Liquid biopsy in ovarian cancer: recent advances on circulating tumor cells and circulating tumor DNA

Ovarian cancer remains the most lethal disease among gynecological malignancies despite the plethora of research studies during the last decades. The majority of patients are diagnosed in an advanced stage and exhibit resistance to standard chemotherapy. Circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) represent the main liquid biopsy approaches that offer a minimally invasive sample collection. Both have shown a diagnostic, prognostic and predictive value in many types of solid malignancies and recent studies attempted to shed light on their role in ovarian cancer. This review is mainly focused on the clinical value of both CTCs and ctDNA in ovarian cancer and, more specifically, on their potential as diagnostic, prognostic and predictive tumor biomarkers.

[Circulating tumor DNA assessment for gynaecological cancers management]

Gynaecological cancers are frequent, with more than 16,000 cases per year in France for 6500 deaths. Few improvements in diagnostic methods, prognostic tools, and therapeutic strategies have occurred in the last two decades. Tumour genomic analyses from, at least in part, the Cancer Genome Atlas have identified some of the molecular alterations involved in gynaecological tumours growth and spreading. However, these data remain incomplete and have not led to dramatic changes in the clinical management of our patients. Moreover, they require invasive samples that are not suitable to objectives like screening/early diagnosis, assessment of treatment efficacy, monitoring of residual disease or early diagnosis of relapse. In the last years, the analysis of circulating tumour biomarkers (also called "liquid biopsies") based on tumour cells (circulating tumour cells) or tumour nucleotides (circulating DNA or RNA) has been massively explored through various indications, platforms, objectives; data related to circulating tumour DNA being the most important in terms of number of publications and interest for clinical practice. This review aims to describe the methods of analysis as well as the observations from the analysis of circulating tumour DNA in gynaecological tumours, from screening/early diagnosis to the adaptation of treatment for advanced stages, through choice of treatments and monitoring of subclinical disease.

[Diagnostic and prognostic value of tumor markers, scores (clinical and biological) algorithms, in front of an ovarian mass suspected of an epithelial ovarian cancer: Article drafted from the French Guidelines in oncology entitled "Initial management of patients with epithelial ovarian cancer" developed by FRANCOGYN, CNGOF, SFOG, GINECO-ARCAGY under the aegis of CNGOF and endorsed by INCa]

OBJECTIVES

To evaluate the diagnostic value of serum/urinary biomarkers and the operability diagnosis strategy to make management recommendations.

METHODS

Bibliographical search in French and English languages by consultation of Pubmed, Cochrane and Embase databases.

RESULTS

For the diagnosis of a suspicious adnexal mass on imaging: Serum CA125 antigen is recommended (grade A). Serum CAE is not recommended (grade C). The low evidence in literature concerning diagnostic value of CA19.9 does not allow any recommendation concerning its use. Serum Human epididymis protein 4 (HE4) is recommended (grade A). Comparison of data concerning diagnosis value of CA125 and HE4 show similar results for the prediction of malignancy in case of a suspicious adnexal mass on imaging (NP1). Urinary HE4 is not recommended (grade A). The use of circulating tumor DNA is not recommended (grade A). Tumor associated antigen-antibodies (AAbs) is not recommended (grade B). The use of ROMA score (Risk of Ovarian Malignancy Algorithm) is recommended (grade A). The use of Copenhagen index (CPH-I), R-OPS score, OVA500 is not recommended (grade C). For the prediction of resectability of an ovarian cancer with peritoneal carcinomatosis in the context of a primary debulking surgery: It is not recommendend to use serum CA125 (grade A). The low evidence in literature concerning diagnostic value of HE4 does not allow any recommendation concerning its use in this context. No recommendation can be given concerning CA19.9 and CAE. For the prediction of resectability of an ovarian cancer with peritoneal carcinomatosis in the context of surgery after neoadjuvant chemotherapy: the low evidence in literature concerning diagnostic value of serum markers in this context does not allow any recommendation concerning their use in this context. Place of laparoscopy for the prediction of resectability in case of upfront surgery of an ovarian cancer with peritoneal carcinomatosis robust data shows that the use of laparoscopy significantly reduce futile laparotomies (LE1). Laparoscopy is recommended in this context (grade A). Fagotti score is a reproducible tool (LE1) permitting the evaluation of feasibility of an optimal upfront debulking (NP4), its use is recommended (grade C). A Fagotti score≥8 is correlated to a low probability of complete or optimal debulking surgery (LE4) (grade C). There is no sufficient evidence to recommend the use of the modified Fagotti score or any other laparoscopic score (LE4). In case of laparotomy for an ovarian cancer with peritoneal carcinomatosis, the use of Peritoneal Cancer Index (PCI) is recommended (grade C). For the prediction of overall survival, disease free survival and the prediction of postoperative complications, the clinical and statistical of actually available tools do not allow any recommendation.

Detecting ovarian cancer using extracellular vesicles: progress and possibilities

Ovarian cancer (OC) is the deadliest gynecological malignancy. Most patients are diagnosed when they are already in the later stages of the disease. Earlier detection of OC dramatically improves the overall survival, but this is rarely achieved as there is a lack of clinically implemented biomarkers of early disease. Extracellular vesicles (EVs) are small cell-derived vesicles that have been extensively studied in recent years. They contribute to various aspects of cancer pathology, including tumor growth, angiogenesis and metastasis. EVs are released from all cell types and the macromolecular cargo they carry reflects the content of the cells from which they were derived. Cancer cells release EVs with altered cargo into biofluids, and so, they represent an excellent potential source of novel biomarkers for the disease. In this review, we describe the latest developments in EVs as potential biomarkers for earlier detection of OC. The field is still relatively young, but many studies have shown that EVs and the cargo they carry, including miRNAs and proteins, can be used to detect OC. They could also give insights into the stage of the disease and predict the likely therapeutic outcome. There remain many challenges to the use of EVs as biomarkers, but, through ongoing research and innovation in this exciting field, there is great potential for the development of diagnostic assays in the clinic that could improve patient outcome.

La biopsie liquide

La biopsie liquide est apparue comme une voie prometteuse pour le dépistage du cancer. En effet, plusieurs biomarqueurs comme les ADN circulants, les cellules tumorales circulantes, les micro-ARN circulants etc. se sont révélés prometteurs pour le théragnostic ou le suivi du patient. La détection précoce peut aider à réduire la mortalité associée au cancer et augmenter la survie globale des patients. La plupart des types de cancer manquent de biomarqueurs spécifiques et le développement de techniques de dépistage efficaces appliquées en clinique a été limité malgré des efforts intenses dans ce domaine. La nature non invasive de la biopsie liquide lui donne un avantage vis-à-vis d’autres méthodes, notamment pour le développement de tests de dépistage du cancer. Les différentes études fondées sur l’analyse de la biopsie liquide dans le but de développer des tests de dépistage et de détection précoce du cancer sont présentées dans cette revue. Bien qu’actuellement aucun test développé à partir de la biopsie liquide s’avère à la fois assez spécifique et sensible pour être utilisé comme test universel de dépistage, le potentiel de cette nouvelle approche apparaît de plus en plus crédible, eu égard aux récents développements de méthodes sophistiquées, notamment multiparamétriques.

Amniotic fluid cell-free DNA in preterm prelabor rupture of membranes

INTRODUCTION

We evaluated the levels of cell-free nuclear DNA (nDNA) and cell-free mitochondrial DNA (mtDNA) in the amniotic fluid supernatant from pregnancies complicated by preterm prelabor rupture of membranes (PPROM) based on evidence of microbial invasion of the amniotic cavity (MIAC) and/or intra-amniotic inflammation (IAI).

MATERIAL AND METHODS

A total of 155 women with PPROM were included in this study. Amniotic fluid samples were obtained by transabdominal amniocentesis. The levels of cell-free nDNA and mtDNA in the amniotic fluid supernatant were assessed and quantified by real-time polymerase chain reaction.

RESULTS

The levels of cell-free nDNA and mtDNA were higher in women with MIAC and IAI than in women without these conditions (nDNA: with MIAC: median 3.9 × 10⁴ genome equivalent [GE]/mL vs without MIAC: median 1.2 × 10⁴  GE/mL, with IAI: median: 5.3 × 10⁴  GE/mL vs without IAI: median 1.2 × 10⁴  GE/mL; mtDNA: with MIAC: median 9.2 × 10⁵  GE/mL vs without MIAC: median 2.5 × 10⁵  GE/mL, with IAI: median 1.1 × 10⁶  GE/mL vs without IAI: median 2.5 × 10⁵ ; all P values ≤ 0.01). Women with the microbial-associated IAI showed the highest levels of cell-free nDNA and mtDNA.

CONCLUSIONS

Cell-free nDNA and mtDNA are constituents of the amniotic fluid supernatant from PPROM pregnancies. Both cell-free nDNA and mtDNA are involved in the intra-amniotic inflammatory response in women with PPROM.

Prognostic value of various subtypes of extracellular DNA in ovarian cancer patients

Background

Patients with ovarian cancer represent a heterogeneous population with a variable prognosis and response to chemotherapy. Plasma DNA has been shown to have a prognostic value in different types of cancer including ovarian carcinoma. Whether total circulating DNA, which can be assessed much easier without knowing the tumor-specific mutations, has similar informative value is currently unknown. The aim of this study was to evaluate the prognostic value of extracellular DNA in advanced ovarian cancer.

Methods

This prospective study included 67 patients (pts) with ovarian cancer treated with 1st line paclitaxel and carboplatin (25 pts) and paclitaxel, carboplatin and bevacizumab (42 pts). Thirty-five patients had optimal surgical debulking before chemotherapy. Extracellular DNA was quantified using real time PCR before administration of chemotherapy (67 pts) and after 6 cycles of chemotherapy (44 pts).

Results

Total extracellular DNA (ecDNA), as well as extracellular DNA of nuclear (nDNA) and mitochondrial origin (mtDNA) significantly (p < 0.05) decreased after 6 cycles of chemotherapy (by 54%, 63% and 52%, respectively. Patients with stage I disease had significantly lower mtDNA compared to patients with stage II-IV (8604 vs. 16, 984 ge/mL, p = 0.03). Patients with lower baseline nDNA had superior progression-free (HR = 0.35 (0.14–0.86)) and overall survival (HR = 0.18 (0.04–0.77). The prognostic value of nDNA was confirmed independent of tumor stage and confirmed in multivariate analysis.

Conclusions

Our data suggest that ecDNA of both, nuclear and mitochondrial origin could be added to prognostic markers in ovarian cancer. Analysis of ecDNA does not require the knowledge of tumor-specific mutations in contrast to the quantification of tumor-derived ecDNA. Study of the dynamics and cell type-specific source of the ecDNA could shed light on its biology in cancer and might help to direct the treatment of ovarian cancer.

Cell-free DNA in blood and urine as a diagnostic tool for bladder cancer: a meta-analysis

OBJECTIVE

To assess the diagnostic performance of cell-free DNA assays in the detection of bladder cancer.

PATIENTS AND METHODS

The quality of the studies included in this meta-analysis was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Statistical analyses were performed using the software RevMan 5.3 and Stata 14.0. We assessed the pooled sensitivity and specificity, positive/negative likelihood ratios (PLRs/NLRs), diagnostic odds ratios (DORs), and corresponding 95% confidence intervals (95% CIs). Summary receiver operating characteristic curve (ROC curve) and area under the curve (AUC) were used to summarize the overall test performance. Heterogeneity and publication bias were also examined.

RESULTS

Eleven studies included 802 bladder cancer patients and 668 controls met the eligibility criteria. The overall diagnostic accuracy was measured as follows: sensitivity 0.71 (95% CI = 0.64-0.77), specificity 0.78 (95% CI = 0.70-0.85), PLR 3.3 (95% CI = 2.4-54.5), NLR 0.37 (95% CI = 0.30-0.46), DOR 9 (95% CI = 6-14), and AUC 0.80 (95% CI = 0.77-0.83). Subgroup analysis suggested that ethnicity significantly accounted for the heterogeneity of specificity. The Deeks' funnel plot asymmetry test (P = 0.97) suggested no potential publication bias.

CONCLUSIONS

Cell-free DNA has a high diagnostic value in bladder cancer.

Circulating cell free DNA as the diagnostic marker for colorectal cancer: a systematic review and meta-analysis

Background

Quantitative analyses of circulating cell-free DNA (cfDNA) are suggested to be a promising method for the detection of colorectal cancer, validated clinical relevance of cfDNA has not been published so far. Though some of the inconsistent results were published. This study is the first meta-analysis to systematically evaluate the diagnostic accuracy of circulating cfDNA as non-invasive biomarkers for colorectal cancer.

Results

Fourteen studies concerning a quantitative analysis of circulating cfDNA for the diagnosis of colorectal cancer met the inclusion criteria. Data includes 1,258 patients with colorectal cancer and 803 healthy individuals as control was analyzed. The summary estimates were as follow: sensitivity, 0.735 (95% CI 0.713–0.757); specificity, 0.918 (95% CI, 0.900–0.934); positive likelihood ratio, 8.295 (95% CI, 5.037–13.659); negative likelihood ratio, 0.300 (95% CI, 0.231–0.391); diagnostic odds ratio, 30.783 (95% CI, 16.965–55.856); and area under the curve, 0.8818 (95% CI, 0.88–0.93), respectively. Publication bias was not evident with Deeks’ funnel plot asymmetry test (p = 0.197).

Materials and Methods

A systematic literature was searched in PubMed, EMBASE, Cochrane Library and Chinese National Knowledge Infrastructure from their inception to August 07, 2017. Analyses were conducted by Meta-DiSc 1.4 and Stata 12.0. Diagnostic accuracy in sensitivity, specificity and aspects were pooled. Subgroup analyses and meta-regression were performed to identify the sources of heterogeneity. Clinical utility of the cfDNA was evaluated by Fagan nomogram.

Conclusions

Our meta-analysis suggested that the diagnostic accuracy of circulating cfDNA has unsatisfactory sensitivity but acceptable specificity for diagnosis of colorectal cancer. Furthermore, the integrity index (ALU247/ALU115) is better than absolute DNA concentration in diagnostic accuracy of colorectal cancer.

Optimization to detect TP53 mutations in circulating cell-free tumor DNA from patients with serous epithelial ovarian cancer

Objective

Circulating cell-free tumor DNA (cfDNA) is the DNA released by apoptotic and necrotic cells of the primary tumor into the blood during the period of tumor development. The cfDNA reflects the genetic and epigenetic alterations of the original tumor. TP53 mutations are a defining feature of high-grade serous ovarian carcinoma. We optimized the methods for detecting TP53 mutations in cfDNA from blood samples. We confirmed the correlation of TP53 mutation in primary ovarian cancer tissue and it in cfDNA using digital polymerase chain reaction (dPCR).

Methods

We found 12 frequent mutation sites in TP53 using The Cancer Genome Atlas and Catalogue of Somatic Mutations in Cancer data and manufactured 12 primers. The mutations in tissues were evaluated in fresh-frozen tissue (FFT) and formalin-fixed paraffin-embedded tissue (FFPET). We performed a prospective analysis of serial plasma samples collected from 4 patients before debulking surgery. We extracted cfDNA and calculated its concentration in blood. dPCR was used to analyze TP53 mutations in cfDNA, and we compared TP53 mutations in ovarian cancer tissue with those in cfDNA.

Results

Ten primers out of 12 detected the presence of TP53 mutations in FFT, FFPET, and cfDNA. In FFT and FFPET tissue, there were no significant differences. The average cfDNA concentration was 2.12±0.59 ng/mL. We also confirmed that mutations of cfDNA and those of FFT were all in R282W site.

Conclusion

This study developed detection methods for TP53 mutations in cfDNA in ovarian cancer patients using dPCR. The results demonstrated that there are the same TP53 mutations in both ovarian cancer tissue and cfDNA.

The Clinical Utility of Cell-Free DNA Measurement in Differentiated Thyroid Cancer: A Systematic Review

BACKGROUND

Cell-free DNA (cfDNA) can be detected in the circulation of healthy individuals, but is found in higher concentrations in cancer patients. Furthermore, mutations in tumor cells can be identified in circulating DNA fragments. This has been the subject of significant interest in the field of cancer research, but little has been published in thyroid cancer.

OBJECTIVES

To assess all available evidence on the use of circulating cfDNA in the diagnosis, management and surveillance of patients with differentiated thyroid cancer, and collate it into a systematic review to guide future research.

METHODS

A comprehensive literature search on the measurement of cfDNA in thyroid cancer was undertaken, and results from relevant studies collated into a systematic review.

RESULTS

Nine studies were identified, with varying methodologies and findings. Key techniques and findings are summarized.

CONCLUSION

There is limited but promising evidence that somatic mutations in thyroid cancer can be detected in circulating cfDNA and are associated with more advanced disease. Further research is required to develop a clinically useful tool based on cfDNA to improve the management of thyroid cancers.

The value of cell-free DNA for molecular pathology

Over the past decade, advances in molecular biology and genomics techniques have revolutionized the diagnosis and treatment of cancer. The technological advances in tissue profiling have also been applied to the study of cell-free nucleic acids, an area of increasing interest for molecular pathology. Cell-free nucleic acids are released from tumour cells into the surrounding body fluids and can be assayed non-invasively. The repertoire of genomic alterations in circulating tumour DNA (ctDNA) is reflective of both primary tumours and distant metastatic sites, and ctDNA can be sampled multiple times, thereby overcoming the limitations of the analysis of single biopsies. Furthermore, ctDNA can be sampled regularly to monitor response to treatment, to define the evolution of the tumour genome, and to assess the acquisition of resistance and minimal residual disease. Recently, clinical ctDNA assays have been approved for guidance of therapy, which is an exciting first step in translating cell-free nucleic acid research tests into clinical use for oncology. In this review, we discuss the advantages of cell-free nucleic acids as analytes in different body fluids, including blood plasma, urine, and cerebrospinal fluid, and their clinical applications in solid tumours and haematological malignancies. We will also discuss practical considerations for clinical deployment, such as preanalytical factors and regulatory requirements. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Clinical relevance of cell-free DNA in gastrointestinal tract malignancy

BACKGROUND

Cell-free DNA (cfDNA) extracted from blood has become a clinically feasible biomarker in various types of cancer. However, the clinical significance of cfDNA in gastrointestinal (GI) tract cancer among Asian populations requires further investigation.

RESULTS

The median cfDNA copy number was highest in esophageal cancer, followed by colorectal cancer and gastric cancer, which were all significantly higher than those of healthy individuals. The cfDNA levels were higher in GI tract cancer, followed by those in carcinoma in situ and then healthy individuals (P = 0.019). During the postoperative surveillance, the cfDNA level tended to be more sensitive than the carcinoembryonic antigen level in predicting recurrence. For recurrent gastric cancer, a persistently high cfDNA level and an increasing trend was observed after surgery. For stage IV colorectal cancer, dynamic changes in the cfDNA level were correlated with the responses to chemotherapy and surgery.

MATERIALS AND METHODS

Blood samples were collected from 95 healthy individuals and from 855 patients diagnosed with GI tract malignancy, including 98 with esophageal cancer, 428 with stomach cancer, 329 with colorectal cancer and 30 with carcinoma in situ. The copy numbers of extracted cfDNA were analyzed and compared among the different types of GI cancers.

CONCLUSIONS

The cfDNA level can serve as a feasible biomarker for detecting tumors in GI tract cancer. The cfDNA level may play a role in predicting tumor responses to chemotherapy and surgery in colorectal cancer; tumor recurrence should be considered in gastric cancer with a persistently high cfDNA level after surgery.

Value of circulating cell-free DNA analysis as a diagnostic tool for breast cancer: a meta-analysis

OBJECTIVES

The aim of this study was to systematically evaluate the diagnostic value of cell free DNA (cfDNA) for breast cancer.

RESULTS

Among 308 candidate articles, 25 with relevant diagnostic screening qualified for final analysis. The mean sensitivity, specificity and area under the curve (AUC) of SROC plots for 24 studies that distinguished breast cancer patients from healthy controls were 0.70, 0.87, and 0.9314, yielding a DOR of 32.31. When analyzed in subgroups, the 14 quantitative studies produced sensitivity, specificity, AUC, and a DOR of 0.78, 0.83, 0.9116, and 24.40. The 10 qualitative studies produced 0.50, 0.98, 0.9919, and 68.45. For 8 studies that distinguished malignant breast cancer from benign diseases, the specificity, sensitivity, AUC and DOR were 0.75, 0.79, 0.8213, and 9.49. No covariate factors had a significant correlation with relative DOR. Deek's funnel plots indicated an absence of publication bias.

MATERIALS AND METHODS

Databases were searched for studies involving the use of cfDNA to diagnose breast cancer. The studies were analyzed to determine sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio (DOR), and the summary receiver operating characteristic (SROC). Covariates were evaluated for effect on relative DOR. Deek's Funnel plots were generated to measure publication bias.

CONCLUSIONS

Our analysis suggests a promising diagnostic potential of using cfDNA for breast cancer screening, but this diagnostic method is not yet independently sufficient. Further work refining qualitative cfDNA assays will improve the correct diagnosis of breast cancers.

Screening for ovarian cancer: imaging challenges and opportunities for improvement

The United Kingdom Collaborative Trial of Ovarian Cancer Screening (UKCTOCS) recently reported a reduction in the average overall mortality among ovarian cancer patients screened with an annual sequential, multimodal strategy that tracked biomarker CA125 over time, where increasing serum CA125 levels prompted ultrasound. However, multiple cases were documented wherein serum CA125 levels were rising, but ultrasound screens were normal, thus delaying surgical intervention. A significant factor which could contribute to false negatives is that many aggressive ovarian cancers are believed to arise from epithelial cells on the fimbriae of the fallopian tubes, which are not readily imaged. Moreover, because only a fraction of metastatic tumors may reach a sonographically-detectable size before they metastasize, annual screening with ultrasound may fail to detect a large fraction of early-stage ovarian cancers. The ability to detect ovarian carcinomas before they metastasize is critical and future efforts towards improving screening should focus on identifying unique features specific to aggressive, early-stage tumors, as well as improving imaging sensitivity to allow for detection of tubal lesions. Implementation of a three-stage multimodal screening strategy in which a third modality is employed in cases where the first-line blood-based assay is positive and the second-line ultrasound exam is negative may also prove fruitful in detecting early-stage cases missed by ultrasound.

Ovarian Cancers: Genetic Abnormalities, Tumor Heterogeneity and Progression, Clonal Evolution and Cancer Stem Cells

Four main histological subtypes of ovarian cancer exist: serous (the most frequent), endometrioid, mucinous and clear cell; in each subtype, low and high grade. The large majority of ovarian cancers are diagnosed as high-grade serous ovarian cancers (HGS-OvCas). TP53 is the most frequently mutated gene in HGS-OvCas; about 50% of these tumors displayed defective homologous recombination due to germline and somatic BRCA mutations, epigenetic inactivation of BRCA and abnormalities of DNA repair genes; somatic copy number alterations are frequent in these tumors and some of them are associated with prognosis; defective NOTCH, RAS/MEK, PI3K and FOXM1 pathway signaling is frequent. Other histological subtypes were characterized by a different mutational spectrum: LGS-OvCas have increased frequency of BRAF and RAS mutations; mucinous cancers have mutation in ARID1A, PIK3CA, PTEN, CTNNB1 and RAS. Intensive research was focused to characterize ovarian cancer stem cells, based on positivity for some markers, including CD133, CD44, CD117, CD24, EpCAM, LY6A, ALDH1. Ovarian cancer cells have an intrinsic plasticity, thus explaining that in a single tumor more than one cell subpopulation, may exhibit tumor-initiating capacity. The improvements in our understanding of the molecular and cellular basis of ovarian cancers should lead to more efficacious treatments.

Circulating cell-free DNA and circulating tumor cells, the "liquid biopsies" in ovarian cancer

Limited understanding of ovarian cancer (OC) genome portrait has hindered the therapeutic advances. The serial monitoring of tumor genotypes is becoming increasingly attainable with circulating cell-free DNA (cf-DNA) and circulating tumor cells (CTCs) emerging as “liquid biopsies”. They represent non-invasive biomarkers and are viable, as they can be isolated from human plasma, serum and other body fluids. Molecular characterization of circulating tumor DNA (ct-DNA) and CTCs offer unique potentials to better understand the biology of metastasis and resistance to therapies. The liquid biopsies may also give innovative insights into the process of rapid and accurate identification, resistant genetic alterations and a real time monitoring of treatment responses. In addition, liquid biopsies are shedding light on elucidating signal pathways involved in invasiveness and metastasis competence; but the detection and molecular characterization of ct-DNA and CTCs are still challenging, since they are rare, and the amount of available samples are very limited. This review will focus on the clinical potential of ct-DNA and CTCs in both the early and advanced diagnosis, prognosis, and in the identification of resistance mutations in OC.