Novel biomarker candidates for the diagnosis of ovarian clear cell carcinoma

From clinical management to personalized medicine: novel therapeutic approaches for ovarian clear cell cancer

Ovarian clear-cell cancer is a rare subtype of epithelial ovarian cancer with unique clinical and biological features. Despite optimal cytoreductive surgery and platinum-based chemotherapy being the standard of care, most patients experience drug resistance and a poor prognosis. Therefore, novel therapeutic approaches have been developed, including immune checkpoint blockade, angiogenesis-targeted therapy, ARID1A synthetic lethal interactions, targeting hepatocyte nuclear factor 1β, and ferroptosis. Refining predictive biomarkers can lead to more personalized medicine, identifying patients who would benefit from chemotherapy, targeted therapy, or immunotherapy. Collaboration between academic research groups is crucial for developing prognostic outcomes and conducting clinical trials to advance treatment for ovarian clear-cell cancer. Immediate progress is essential, and research efforts should prioritize the development of more effective therapeutic strategies to benefit all patients.

Serum Free Fatty Acid Changes Caused by High Expression of Stearoyl-CoA Desaturase 1 in Tumor Tissues Are Early Diagnostic Markers for Ovarian Cancer

Ovarian cancer has a poor prognosis and is difficult to detect in early stages. Therefore, developing new diagnostic markers for early-stage ovarian cancer is critical. Here, we developed a diagnostic marker for early-stage ovarian cancer on the basis of fatty acid metabolism characteristics of cancer cells. The expression of various fatty acid metabolizing enzymes such as stearoyl-CoA desaturase 1 (SCD1) was altered in early-stage ovarian cancer tissue compared with that in normal ovarian tissue. Changes in the expression of fatty acid metabolizing enzymes, particularly SCD1, in cancer tissues were found to alter concentrations of multiple free fatty acids (FFA) in serum. We were the first to show that fatty acid metabolic characteristics in tissues are related to the FFA composition of serum. Surprisingly, patients with stage I/II ovarian cancer also showed significant changes in serum levels of eight FFAs, which can be early diagnostic markers. Finally, using statistical analysis, an optimal early diagnostic model combining oleic and arachidic acid levels, fatty acids associated with SCD1, was established and confirmed to have higher diagnostic power than CA125, regardless of histology. Thus, our newly developed diagnostic model using serum FFAs may be a powerful tool for the noninvasive early detection of ovarian cancer.

SIGNIFICANCE

Measurement of serum FFA levels by changes in the expression of fatty acid metabolizing enzymes in tumor tissue would allow early detection of ovarian cancer. In particular, the SCD1-associated FFAs, oleic and arachidic acid, would be powerful new screening tools for early-stage ovarian cancer.

Clinical perspectives of rare ovarian tumors: clear cell ovarian cancer

Ovarian clear cell carcinoma (OCCC) is a rare and distinct histological type of epithelial ovarian carcinoma in terms of its histopathological, clinical and genetic features. Patients with OCCC are younger and diagnosed at earlier stages than those with the most common histological type-high-grade serous carcinoma. Endometriosis is considered a direct precursor of OCCC. Based on preclinical data, the most frequent gene alternations in OCCC are mutations of AT-rich interaction domain 1A and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha. The prognosis of patients with early-stage OCCC is favorable, whereas patients at an advanced stage or who have the recurrent disease have a dismal prognosis due to OCCC's resistance to standard platinum-based chemotherapy. Despite a lower rate of response due to its resistance to standard platinum-based chemotherapy, the treatment strategy for OCCC resembles that of high-grade serous carcinoma, which includes aggressive cytoreductive surgery and adjuvant platinum-based chemotherapy. Alternative treatment strategies, including biological agents based on molecular characteristics specific to OCCC, are urgently needed. Furthermore, due to its rarity, well-designed collaborative international clinical trials are needed to improve oncologic outcomes and the quality of life in patients with OCCC.

Next-Generation Intelligent MXene-Based Electrochemical Aptasensors for Point-of-Care Cancer Diagnostics

Delayed diagnosis of cancer using conventional diagnostic modalities needs to be addressed to reduce the mortality rate of cancer. Recently, 2D nanomaterial-enabled advanced biosensors have shown potential towards the early diagnosis of cancer. The high surface area, surface functional groups availability, and excellent electrical conductivity of MXene make it the 2D material of choice for the fabrication of advanced electrochemical biosensors for disease diagnostics. MXene-enabled electrochemical aptasensors have shown great promise for the detection of cancer biomarkers with a femtomolar limit of detection. Additionally, the stability, ease of synthesis, good reproducibility, and high specificity offered by MXene-enabled aptasensors hold promise to be the mainstream diagnostic approach. In this review, the design and fabrication of MXene-based electrochemical aptasensors for the detection of cancer biomarkers have been discussed. Besides, various synthetic processes and useful properties of MXenes which can be tuned and optimized easily and efficiently to fabricate sensitive biosensors have been elucidated. Further, futuristic sensing applications along with challenges will be deliberated herein.

Multi-modal Profiling of the Extracellular Matrix of Human Fallopian Tubes and Serous Tubal Intraepithelial Carcinomas

Recent evidence supports the fimbriae of the fallopian tube as one origin site for high-grade serous ovarian cancer (HGSOC). The progression of many solid tumors is accompanied by changes in the microenvironment, including alterations of the extracellular matrix (ECM). Therefore, we sought to determine the ECM composition of the benign fallopian tube and changes associated with serous tubal intraepithelial carcinomas (STICs), precursors of HGSOC. The ECM composition of benign human fallopian tube was first defined from a meta-analysis of published proteomic datasets that identified 190 ECM proteins. We then conducted de novo proteomics using ECM enrichment and identified 88 proteins, 7 of which were not identified in prior studies (COL2A1, COL4A5, COL16A1, elastin, LAMA5, annexin A2, and PAI1). To enable future in vitro studies, we investigated the levels and localization of ECM components included in tissue-engineered models (type I, III, and IV collagens, fibronectin, laminin, versican, perlecan, and hyaluronic acid) using multispectral immunohistochemical staining of fimbriae from patients with benign conditions or STICs. Quantification revealed an increase in stromal fibronectin and a decrease in epithelial versican in STICs. Our results provide an in-depth picture of the ECM in the benign fallopian tube and identified ECM changes that accompany STIC formation. (J Histochem Cytochem XX: XXX-XXX, XXXX).

Identification of biomarkers for the diagnosis and targets for therapy in patients with clear cell ovarian cancer: a systematic literature review

Clear cell ovarian cancer (CCOC) is a rare type of epithelial cancer often resistant to platinum-based chemotherapy. Biomarkers for the diagnosis of CCOC, and targets for immunotherapy, both have the potential to improve outcomes for patients. Our review aims to determine whether any antigens already identified in the literature could fulfil this remit. PubMed, Medline, Web of Science, Scopus, Cochrane, CINAHL and EMBASE were searched and included all reported studies up until August 2021. Primary research articles on human adult females including at least 10 CCOC patients were included. Quality assurance was carried out using a modified version of the QUADAS-2 tool. Sensitivity, specificity and area under the curve were extracted from each included study by two independent reviewers. Twenty-three articles were included which identified 19 gene transcripts/proteins and one antibody, with reported sensitivities between 21% and 100% and specificities between 0% and 100% for expression in CCOC and differentiation from other epithelial ovarian cancer subtypes, benign gynaecological disease or normal tissue. Twelve studies identified biomarkers with a sensitivity and specificity above 80%. A panel of biomarkers consisting of IMP3, napsin A and hepatocyte nuclear factor 1 beta achieved the highest area under the curve of 0.954. This review demonstrates that there are promising candidate biomarkers for the diagnosis of CCOC, some of which are highly specific, and have the potential to act as targets for therapy. However, larger cohort studies are needed to validate these biomarkers and their potential use in clinical practice.

Toward an understanding of tissue factor pathway inhibitor-2 as a novel serodiagnostic marker for clear cell carcinoma of the ovary

AIMS

Tissue factor pathway inhibitor (TFPI)-2 has recently emerged as a serodiagnostic marker for patients with epithelial ovarian cancer (EOC), especially clear cell carcinoma (CCC). This review discusses the biological properties of TFPI-2 and why serum levels are elevated in CCC patients.

METHODS

A comprehensive literature search was conducted in PubMed up until March, 2021.

RESULTS

TFPI-2 is a Kunitz-type protease inhibitor and negatively regulates the enzymatic activities, such as plasmin. TFPI-2 has been characterized as a tumor suppressor gene and was frequently downregulated through promoter hypermethylation in various human cancers. In contrast, TFPI-2 was overexpressed only in CCC. TFPI-2 may be involved in the pathophysiology of CCC, possibly through regulation of coagulation system, stabilization of extracellular matrix (ECM), and induction of intracellular signal transduction. TFPI-2 suppresses tissue factor-induced hypercoagulation in a hypoxic environment. TFPI-2, secreted by CCC cells, platelets, and adjacent vascular endothelial cells, may suppress tumor growth and invasion through ECM remodeling. Nuclear TFPI-2 may suppress matrix metalloproteinase production via transcription factors and modulate caspase-mediated cell apoptosis. CCC cells may upregulate the TFPI-2 expression to adapt to survival in the demanding environment. TFPI-2 is secreted by CCC cells and enters the systemic circulation, resulting in elevated blood levels.

DISCUSSION

Serum TFPI-2 reflects the overexpression of TFPI-2 in CCC tissues and is a potential serodiagnostic marker. Further research is needed to explore the expression, clinical significance, biological function, and potential mechanism of TFPI-2 in CCC.

Validation of tissue factor pathway inhibitor 2 as a specific biomarker for preoperative prediction of clear cell carcinoma of the ovary

BACKGROUND

Tissue factor pathway inhibitor 2 (TFPI2) is a novel serum biomarker that discriminates ovarian clear cell carcinoma (CCC) from borderline ovarian tumors (BOTs) and non-clear cell epithelial ovarian cancers (EOCs). Here, we examined the performance of TFPI2 for preoperative diagnosis of CCC.

METHODS

Serum samples were obtained preoperatively from patients with ovarian masses, who needed surgical treatment at five hospitals in Japan. The diagnostic powers of TFPI2 and cancer antigen 125 (CA125) serum levels to discriminate CCC from BOTs, other EOCs, and benign lesions were compared.

RESULTS

A total of 351 patients including 69 CCCs were analyzed. Serum TFPI2 levels were significantly higher in CCC patients (mean ± SD, 508.2 ± 812.0 pg/mL) than in patients with benign lesions (154.7 ± 46.5), BOTs (181 ± 95.5) and other EOCs (265.4 ± 289.1). TFPI2 had a high diagnostic specificity for CCC (79.5%). In patients with benign ovarian endometriosis, no patient was positive for TFPI2, but 71.4% (15/21) were CA125 positive. TFPI2 showed good performance in discriminating stage II-IV CCC from BOTs and other EOCs (AUC 0.815 for TFPI2 versus 0.505 for CA125) or endometriosis (AUC 0.957 for TFPI2 versus 0.748 for CA125). The diagnostic sensitivity of TFPI2 to discriminate CCC from BOTs and other EOCs was improved from 43.5 to 71.0% when combined with CA125.

CONCLUSIONS

High specificity of TFPI2 for preoperative detection of CCC was verified with the defined cutoff level of TFPI2 in clinical practice. TFPI2 and CA125 may contribute substantially to precise prediction of intractable CCC.

Clinical characteristics and prognosis of ovarian clear cell carcinoma: a 10-year retrospective study

Background

Ovarian clear cell carcinoma (OCCC) is a special pathological type of epithelial ovarian carcinoma (EOC). We conducted this research to investigate the clinical characteristics and outcomes of OCCC and to provide additional supporting evidence to aid in the clinical diagnosis and management.

Methods

This was a retrospective study investigating the clinical characteristics and survival outcomes of 86 patients with OCCC treated at our center between January 2010 and March 2020. Survival analysis was also performed on 179 patients with OCCC obtained from the Surveillance, Epidemiology and End Results (SEER) cancer registry database.

Results

The median age of participants was 49.21 ± 9.91 years old, and 74.42% of them were diagnosed at early stage. The median CA125 level was 601.48 IU/mL, while 19.77% of the patients had normal CA125 levels. Sixteen patients (18.60%) had co-existing endometriosis and 8 patients (9.3%) developed venous thromboembolism (VTE). There were 5 patients received suboptimal cytoreduction. Sixty-six patients (76.74%) underwent lymphadenectomy, and only 3 (4.55%) patients had positive lymph nodes. Patients diagnosed at an early stage had higher 3-year overall survival (OS) and progression-free survival (PFS) rates than those with advanced stage OCCC. CA19–9 (P = 0.025) and ascites (P = 0.001) were significantly associated with OS, while HE4 (P = 0.027) and ascites (P = 0.001) were significantly associated with PFS. Analysis of data from the SEER database showed that positive lymph nodes is also an independent prognostic factor for OS (P = 0.001).

Conclusions

OCCC often presents at an early stage and young age with a mildly elevated CA125. CA19–9, HE4, massive ascites, and positive lymph node are independent prognostic factors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08061-7.

Updates of Pathogenesis, Diagnostic and Therapeutic Perspectives for Ovarian Clear Cell Carcinoma

Ovarian clear cell carcinoma (OCCC) is a special pathological type of epithelial ovarian carcinoma (EOC) and has a high prevalence in Asia without specific molecular subtype classification. Endometriosis is a recognized precancerous lesion that carries 3-fold increased risk of OCCC. Ovarian endometrioid carcinoma, which also originates from endometriosis, shares several features with OCCC, including platinum resistance and younger age at diagnosis. Patients with OCCC have about a 2.5 to 4 times greater risk of having a venous thromboembolism (VTE) compared with other EOC, and OCCC tends to metastasize through lymphatic vesicular and peritoneal spread as opposed to hematogenous metastasis. There is only mild elevation of the conventional biomarker CA125. Staging surgery or optimal cytoreduction combined with chemotherapy is a common therapeutic strategy for OCCC. However, platinum resistance commonly portends a poor prognosis, so novel treatments are urgently needed. Targeted therapy and immunotherapy are currently being studied, including PARP, EZH2, and ATR inhibitors combined with the synthetic lethality of ARID1A-dificiency, and MAPK/PI3K/HER2, VEGF/bFGF/PDGF, HNF1β, and PD-1/PD-L1 inhibitors. Advanced stage, suboptimal cytoreduction, platinum resistance, lymph node metastasis, and VTE are major prognostic predictors for OCCC. We focus on update pathogenesis, diagnostic methods and therapeutic approaches to provide future directions for clinical diagnosis and treatment of OCCC.

An AFM-Based Nanomechanical Study of Ovarian Tissues with Pathological Conditions

BACKGROUND

Different diseases affect both mechanical and chemical features of the involved tissue, enhancing the symptoms.

METHODS

In this study, using atomic force microscopy, we mechanically characterized human ovarian tissues with four distinct pathological conditions: mucinous, serous, and mature teratoma tumors, and non-tumorous endometriosis. Mechanical elasticity profiles were quantified and the resultant data were categorized using K-means clustering method, as well as fuzzy C-means, to evaluate elastic moduli of cellular and non-cellular parts of diseased tissues and compare them among four disease conditions. Samples were stained by hematoxylin-eosin staining to further study the content of different locations of tissues.

RESULTS

Pathological state vastly influenced the mechanical properties of the ovarian tissues. Significant alterations among elastic moduli of both cellular and non-cellular parts were observed. Mature teratoma tumors commonly composed of multiple cell types and heterogeneous ECM structure showed the widest range of elasticity profile and the stiffest average elastic modulus of 14 kPa. Samples of serous tumors were the softest tissues with elastic modulus of only 400 Pa for the cellular part and 5 kPa for the ECM. Tissues of other two diseases were closer in mechanical properties as mucinous tumors were insignificantly stiffer than endometriosis in cellular part, 1300 Pa compared to 1000 Pa, with the ECM average elastic modulus of 8 kPa for both.

CONCLUSION

The higher incidence of carcinoma out of teratoma and serous tumors may be related to the intense alteration of mechanical features of the cellular and the ECM, serving as a potential risk factor which necessitates further investigation.

High glypican-3 expression characterizes a distinct subset of ovarian clear cell carcinomas in Canadian patients: an opportunity for targeted therapy

The expression frequency and distribution of glypican-3 (GPC3) was retrospectively assessed by immunohistochemistry in 316 accurately phenotyped ovarian clear cell carcinoma (OCCC) specimens from Canadian patients. The study aimed to evaluate the prevalence of this biomarker in OCCC in a mixed-ethnicity Canadian population and to evaluate associations of GPC3 expression with clinicopathological parameters. Tissue microarrays with napsin A or HNF1β positive and WT1-negative OCCC specimens were evaluated using a GPC3 antibody clone 1G12. Membranous, cytoplasmic, and Golgi pattern GPC3 expression was noted in 184 of 316 (58.2%) cases; 63 of 316 (20%) cases showed high GPC3 expression (>50% of tumor cells were positive). GPC3 expression was not associated with age, stage, and residual disease after primary surgery. High GPC3 expression did not correlate with a specific morphological pattern or the presence of endometriosis. Furthermore, GPC3 expression was not significantly associated with survival in the entire cohort. Statistically significant association of high GPC3 expression was noted with higher body mass index, napsin A positivity, estrogen receptor (ER) negativity, and ARID1A retention. In a stratified analysis by ARID1A status, high GPC3 expression was significantly associated with unfavorable outcomes in cases with loss of ARID1A (n=10; log rank p=0.0048). Women diagnosed with OCCC and high GPC3 expression were also more likely to receive adjuvant chemotherapy. Considering the tumor-specific membranous expression of GPC3 in 58% of cases and high interobserver reproducibility, GPC3 immunohistochemistry is a robust predictive test for inclusion in clinical trials for GPC3-targeted therapies for OCCC.

Napsin-A, a Possible Diagnostic Marker for Differentiating Clear Cell Ovarian Carcinoma From Other High-grade Ovarian Carcinomas

Ovarian clear cell carcinoma (CCC) is divergent from other types of epithelial ovarian carcinoma in terms of clinicopathologic and molecular features. It should be separated from other high-grade carcinomas of the ovary for appropriate treatment. Napsin A is a reliable marker for adenocarcinoma of the lungs, but its role in ovarian epithelial carcinomas is vague. We investigated the expression of a panel of TTF-1, paired box 8, estrogen receptor, Wilms tumor 1, and Napsin A in 100 cases of high-grade ovarian carcinomas. All the examined cases were TTF-1 negative and paired box 8 positive. The 2 biomarkers estrogen receptor together with Wilms tumor 1 can separate CCC from endometriod carcinoma, yet this cannot be carried out in the case of serous and mucinous carcinomas of high grade. Napsin A can differentiate CCC with high sensitivity and specificity. It can be concluded that Napsin A is a sensitive and specific marker for CCC of the ovary. However, an entire marker panel may be useful for distinguishing ovarian CCC from other mimics.

Conceptual frameworks of synthetic lethality in clear cell carcinoma of the ovary

Targeting non-oncogenes may result in the selective death of cancer cells. Clear cell carcinoma of the ovary (CCC) may exhibit resistance against conventional chemotherapy and is associated with poor prognosis. The aim of the present report was to review synthetic lethality-based therapies for CCC. Previous English-language studies were reviewed to accumulate preclinical and clinical data on targeting synthetic lethal partners. Synthetic lethal interactions have a variety of types, involving components of a backup or parallel pathway with overlapping functions, components encoded by paralogous pairs, subunit components that form heteromeric complexes and components that are arranged in a single linear pathway. A set of candidate gene targets potentially resulting in synthetic lethality have been previously identified. HNF class homeobox, AT-rich interaction domain 1A, ATR serine/threonine kinase, ATM serine/threonine kinase, checkpoint kinase 1 and phosphatase and tensin homolog may be the key partner genes. A variety of loss of function genes in CCC are driver or passenger events and may function as synthetic lethal pairs under replication stress conditions. Further clinical studies will be required to investigate the safety and therapeutic effect of synthetic lethality pairs in CCC tumor types with replication stress.

Candidate synthetic lethality partners to PARP inhibitors in the treatment of ovarian clear cell cancer

Inhibitors of poly(ADP-ribose) polymerase (PARP) are new types of personalized treatment of relapsed platinum-sensitive ovarian cancer harboring BRCA1/2 mutations. Ovarian clear cell cancer (CCC), a subset of ovarian cancer, often appears as low-stage disease with a higher incidence among Japanese. Advanced CCC is highly aggressive with poor patient outcome. The aim of the present study was to determine the potential synthetic lethality gene pairs for PARP inhibitions in patients with CCC through virtual and biological screenings as well as clinical studies. We conducted a literature review for putative PARP sensitivity genes that are associated with the CCC pathophysiology. Previous studies identified a variety of putative target genes from several pathways associated with DNA damage repair, chromatin remodeling complex, PI3K-AKT-mTOR signaling, Notch signaling, cell cycle checkpoint signaling, BRCA-associated complex and Fanconi's anemia susceptibility genes that could be used as biomarkers or therapeutic targets for PARP inhibition. BRCA1/2, ATM, ATR, BARD1, CCNE1, CHEK1, CKS1B, DNMT1, ERBB2, FGFR2, MRE11A, MYC, NOTCH1 and PTEN were considered as candidate genes for synthetic lethality gene partners for PARP interactions. When considering the biological background underlying PARP inhibition, we hypothesized that PARP inhibitors would be a novel synthetic lethal therapeutic approach for CCC tumors harboring homologous recombination deficiency and activating oncogene mutations. The results showed that the majority of CCC tumors appear to have indicators of DNA repair dysfunction similar to those in BRCA-mutation carriers, suggesting the possible utility of PARP inhibitors in a subset of CCC.

E-Cadherin repression increases amount of cancer stem cells in human A549 lung adenocarcinoma and stimulates tumor growth

Here we show that cancer stem cells amount in human lung adenocarcinoma cell line A549 depends on E-cadherin expression. In fact, downregulation of E-cadherin expression enhanced expression of pluripotent genes (c-MYC, NESTIN, OCT3/4 and SOX2) and enriched cell population with the cells possessing the properties of so-called 'cancer stem cells' via activation of Wnt/β-catenin signaling. Repression of E-cadherin also stimulated cell proliferation and migration in vitro, decreased cell amount essential for xenografts formation in nude mice, increased tumors vascularization and growth. On the other hand, E-cadherin upregulation caused opposite effects i.e. diminished the number of cancer stem cells, decreased xenograft vascularization and decelerated tumor growth. Therefore, agents restoring E-cadherin expression may be useful in anticancer therapy.

Reciprocal links between venous thromboembolism, coagulation factors and ovarian cancer progression

Ovarian cancer is the most lethal gynecological malignancy, which is due to late presentation. Treating advanced stage ovarian cancer is difficult, and tumor recurrence and chemoresistance frequently occur. In addition, early detection remains a major challenge as there are no early warning signs and no appropriate biomarkers. To reduce mortality rates of ovarian cancer patients, novel drug targets and biomarkers are needed. We postulate that hemostatic keyplayers are of importance when combatting ovarian cancer. The majority of ovarian cancer patients have abnormal hemostatic blood serum marker levels, which indicate an activated coagulation system. This makes patients more prone to experiencing venous thromboembolism (VTE), and the occurrence of VTE in ovarian cancer patients adversely affects survival. Coagulation activation also promotes tumor progression as it influences tumor biology at several stages and the decreased survival rates associated with ovarian cancer-associated thrombosis are more likely due to cancer metastasis rather than to fatal thromboembolic events. In this review, we will discuss; (1) Population studies that address the bidirectional relationship between VTE and ovarian cancer, and the most important risk factors involved; (2) The mechanisms of coagulation factors and platelets that are critically involved in the development of VTE, and the progression of ovarian cancer; (3) Roles and future directions of coagulation factors in ovarian cancer therapy, and in diagnosis and prognosis of ovarian cancer as biomarkers.

Clinical Significance of Tissue Factor Pathway Inhibitor 2, a Serum Biomarker Candidate for Ovarian Clear Cell Carcinoma

BACKGROUND

There is currently no reliable serum biomarker for ovarian clear cell carcinoma (CCC), a highly lethal histological subtype of epithelial ovarian cancer (EOC). Previously, using a proteome-based approach, we identified tissue factor pathway inhibitor 2 (TFPI2) as a candidate serum biomarker for CCC. In this study, we sought to evaluate the clinical diagnostic performance of TFPI2 in preoperative prediction of CCC.

METHODS

Serum TFPI2 levels were measured in serum samples from a retrospective training set consisting of patients with benign and borderline ovarian tumors, EOC subtypes, and uterine diseases. Via receiver operating characteristic (ROC) analyses, we compared the diagnostic performance of TFPI2 with that of CA125 in discrimination of patients with ovarian CCC from other patient groups. The observed diagnostic performances were examined in a prospective validation set.

RESULTS

The 268-patient training set included 29 patients with ovarian CCC. Unlike CA125, which was also elevated in patients with endometriosis and several EOC subtypes, serum TFPI2 levels were specifically elevated only in ovarian CCC patients, consistent with the mRNA expression pattern in tumor tissues. The area under the ROC curve (AUC) of serum TFPI2 was obviously higher than that of CA125 for discrimination of CCC from other ovarian diseases (AUC = 0.891 versus 0.595). Applying a cut-off value of 280 pg/mL, TFPI2 could distinguish early-stage (FIGO I and II) CCC from endometriosis with 72.2% sensitivity, 93.3% specificity, and 88.8% accuracy. Similar results were confirmed in an independent 156-patient prospective validation set.

CONCLUSIONS

TFPI2 is a useful serum biomarker for preoperative clinical diagnosis of CCC.