Tetranectin Research Articles

Quantitative proteomics analysis of COVID-19 patients: Fetuin-A and tetranectin as potential modulators of innate immune responses

Treatment of severe cases of coronavirus disease 2019 (COVID-19) is extremely important to minimize death and end-organ damage. Here we performed a proteomic analysis of plasma samples from mild, moderate and severe COVID-19 patients. Analysis revealed differentially expressed proteins and different therapeutic potential targets related to innate immune responses such as fetuin-A, tetranectin (TN) and paraoxonase-1 (PON1). Furthermore, protein changes in plasma showed dysregulation of complement and coagulation cascades in COVID-19 patients compared to healthy controls. In conclusion, our proteomics data suggested fetuin-A and TN as potential targets that might be used for diagnosis as well as signatures for a better understanding of the pathogenesis of COVID-19 disease.

The adipocyte-enriched secretory protein tetranectin exacerbates type 2 diabetes by inhibiting insulin secretion from β cells.

Pancreatic β cell failure is a hallmark of diabetes. However, the causes of β cell failure remain incomplete. Here, we report the identification of tetranectin (TN), an adipose tissue–enriched secretory molecule, as a negative regulator of insulin secretion in β cells in diabetes. TN expression is stimulated by high glucose in adipocytes via the p38 MAPK/TXNIP/thioredoxin/OCT4 signaling pathway, and elevated serum TN levels are associated with diabetes. TN treatment greatly exacerbates hyperglycemia in mice and suppresses glucose-stimulated insulin secretion in islets. Conversely, knockout of TN or neutralization of TN function notably improves insulin secretion and glucose tolerance in high-fat diet–fed mice. Mechanistically, TN binds with high selectivity to β cells and inhibits insulin secretion by blocking L-type Ca2+ channels. Our study uncovers an adipocyte–β cell cross-talk that contributes to β cell dysfunction in diabetes and suggests that neutralization of TN levels may provide a new treatment strategy for type 2 diabetes.

Exogenous Tetranectin Alleviates Pre-formed-fibrils-induced Synucleinopathies in SH-SY5Y Cells by Activating the Plasminogen Activation System.

Parkinson's disease (PD) is a common neurodegenerative disease. Previously we identified tetranectin (TN) as a differentially expressed protein in the cerebrospinal fluid of PD patients, and we were surprised to find that TN knockout mice developed PD features. However, the specific role of TN in PD has not been clarified. In this study, we aimed to determine the effect of exogenous TN on cellular PD models and elucidate the underlying mechanisms. We found that exogenous TN could alleviate pre-formed-fibrils (PFFs)-induced synucleinopathies in SH-SY5Y cells and reduce the cell-to-cell transmission of α-synuclein (SYN). We also found that TN can promote the degradation of SYN by plasmin, which may account for its effect on cellular PD models. Moreover, administration of SYN/PFFs decreased the expression of TN and increased the expression of plasminogen activator inhibitor-1 (PAI-1) in SH-SY5Y cells, thereby reducing plasmin activity. Our findings depict a possible SYN-TN-plasmin interaction in which elevated levels of extracellular SYN monomers and aggregates in PD diminish the production of TN and PAI-1. Such changes lead to a reduced plasmin activity, which in turn reduces the degradation of extracellular SYN, thus forming a vicious cycle.

Adipogenic function of tetranectin mediated by enhancing mitotic clonal expansion via ERK signaling

Tetranectin (TN), an adipogenic serum protein, enhances adipocyte differentiation, however, its functional mechanism has yet to be elucidated. In the present study, we investigated the adipogenic function of TN by using medium containing TN-depleted fetal bovine serum (TN-del-FBS) and recombinant mouse TN (mTN). The adipocyte differentiation of 3T3-L1 cells was significantly enhanced by mTN supplementation essentially at differentiation induction, which indicated a potential role of the protein in the early differentiation phase. The adipogenic effect of mTN was more significant with insulin in the differentiation induction cocktail, implicating their close functional relationship. mTN enhanced not only the proliferation of growing cells, but also mitotic clonal expansion (MCE) that is a prerequisite for adipocyte differentiation in the early phase. Consistently, mTN increased the phosphorylation of ERK in the early phase of adipocyte differentiation. Results of this study demonstrate that the adipogenic function of mTN is mediated by enhancing MCE via ERK signaling.

Docosahexaenoic Acid Suppresses Expression of Adipogenic Tetranectin through Sterol Regulatory Element-Binding Protein and Forkhead Box O Protein in Pigs.

Tetranectin (TN), a plasminogen-binding protein originally involved in fibrinolysis and bone formation, was later identified as a secreted adipokine from human and rat adipocytes and positively correlated with adipogenesis and lipid metabolism in adipocytes. To elucidate the nutritional regulation of adipogenic TN from diets containing different sources of fatty acids (saturated, n-6, n-3) in adipocytes, we cloned the coding region of porcine TN from a cDNA library and analyzed tissue expressions in weaned piglets fed with 2% soybean oil (SB, enriched in n-6 fatty acids), docosahexaenoic acid oil (DHA, an n-3 fatty acid) or beef tallow (BT, enriched in saturated and n-9 fatty acids) for 30 d. Compared with tissues in the BT- or SB-fed group, expression of TN was reduced in the adipose, liver and lung tissues from the DHA-fed group, accompanied with lowered plasma levels of triglycerides and cholesterols. This in vivo reduction was also confirmed in porcine primary differentiated adipocytes supplemented with DHA in vitro. Then, promoter analysis was performed. A 1956-bp putative porcine TN promoter was cloned and transcription binding sites for sterol regulatory-element binding protein (SREBP)-1c or forkhead box O proteins (FoxO) were predicted on the TN promoter. Mutating binding sites on porcine TN promoters showed that transcriptional suppression of TN by DHA on promoter activity was dependent on specific response elements for SREBP-1c or FoxO. The inhibited luciferase promoter activity by DHA on the TN promoter coincides with reduced gene expression of TN, SREBP-1c, and FoxO1 in human embryonic kidney HEK293T cells supplemented with DHA. To conclude, our current study demonstrated that the adipogenic TN was negatively regulated by nutritional modulation of DHA both in pigs in vivo and in humans/pigs in vitro. The transcriptional suppression by DHA on TN expression was partly through SREBP-1c or FoxO. Therefore, down-regulation of adipogenic tetranectin associated with fibrinolysis and adipogenesis may contribute to the beneficial effects of DHA on ameliorating obesity-induced metabolic syndromes such as atherosclerosis and adipose dysfunctions.

Adipogenic function of mouse tetranectin and identification of its functional domain

Tetranectin (TN), a plasminogen (Plg) binding protein, enhances the Plg activator (PA)-catalyzed activation of Plg to plasmin (Pln). Previously, TN was identified as an adipogenic serum protein, which promotes adipocyte differentiation. In the present study, we investigated the adipogenic function of mouse TN using recombinant proteins (rmTNs) in full-length and domain-truncated forms. Adipocyte differentiation in TN-depleted-FBS-media was significantly enhanced by rmTNs supplementation. The adipogenic effect of rmTNs was found to be dependent on the presence of a Plg binding domain, indicating the domain is essential for the adipogenic function of mTN. In addition, these results suggested the involvement of Plg activation, however Plg, PA and Pln appeared to have no direct effect on adipocyte differentiation. This study demonstrates the adipogenic function of mTN, which is dependent on the Plg binding domain as its functional domain.

The relationship between the expression of TN and the efficiency of posterior spinal V osteotomy in patients with traumatic kyphosis.

Background:This study was conducted with the aim to investigate the relationship between Tetranectin (TN) and efficiency of posterior spinal V osteotomy in patients with traumatic kyphosis.Methods:Ninety-two patients with traumatic kyphosis admitted in our hospital from February 2014 to June 2016 were included whose serum TN levels were examined by ELISA. Using the mean level of TN as cut-off value, patients were classified into TN high level group (group I) and TN low level group (group II). The observation indexes, including operation time, intra-operational loss of blood, Cobb angle, postoperative complications and recurrence rate of kyphosis within post-operational 6 months were recorded for comparison.Results:TN level was significantly higher in group I [(6.19 ± 0.33) μmol/L] than that in group II [(5.29 ± 0.34) μmol/L] (P < .05). There was no significant difference in average age, sex, lesion site and average time from injury to operation between the two groups (all P > 0.05). Compared to group II, operation time in group I was significantly shortened (5.02 ± 1.15 VS 4.58 ± 0.53, P = .023), the intra-operational loss of blood decreased (2418.56 ± 362.06 VS 2235.84 ± 325.63, P = .013), post-operational Cobb angle decreased (11.10 ± 1.31 VS 6.93 ± 1.04, P = .000), and the incidence of postoperative complications (nail-breaking, rod-breaking and looseness) and recurrence rate decreased (18.8% VS 4.5%, P = .036; 10.4% VS 0.0%, P = .028).Conclusion:Serum TN level is proved to be related to the efficiency of posterior spinal V osteotomy in patients with traumatic kyphosis, and may serve as a possible indicator for clinical treatment.

Immunogenicity, Inflammation, and Lipid Accumulation in Cynomolgus Monkeys Infused with a Lipidated Tetranectin-ApoA-I Fusion Protein

High density lipoprotein (HDL)-targeted therapies, which promote cholesterol efflux from cells, are currently in development for reducing cardiovascular events in acute coronary syndrome. Human apolipoprotein A-I (apoA-I), the major HDL protein, was fused to the trimerization domain of tetranectin (TN) and complexed with phospholipids to generate a HDL mimetic (lipidated TN-ApoA-I) with reduced renal clearance and enhanced efficacy. Cynomolgus monkeys received 24-h intravenous infusions of control, 100 mg/kg or 400 mg/kg lipidated TN-ApoA-I every 4 days for 3 weeks, followed by a 6-week recovery period. After multiple infusions of lipidated TN-ApoA-I, clinical condition deteriorated and was accompanied by changes indicative of a progressive inflammatory response; increased levels of cytokines, C-reactive protein and vascular/perivascular infiltrates in multiple tissues. Rapid formation of antidrug antibodies occurred in all animals receiving lipidated TN-ApoA-I. Enhanced drug clearance corresponding to a relative lack of high molecular weight immune complexes in blood, suggestive of preferred removal/clearance, was observed in some animals. Expected dose-dependent increases in serum lipids were accompanied by vacuolated monocytes/macrophages in multiple organs, which in the glomeruli were shown to be CD68-positive, contain lipid and co-localized with granular IgG deposits. Lipid accumulation may have been a direct result of a high drug load, possibly enhanced by immune complex formation, inflammation, and altered lipid metabolism. Noteworthy was the inter- individual inconsistency in the severity of clinical and histopathologic findings, drug clearance and inflammatory markers. In conclusion, multiple infusions of lipidated TN-ApoA-I resulted in high immunogenicity, lipid accumulation and were not well tolerated in nonhuman primates.

Tetranectin as a Potential Biomarker for Stable Coronary Artery Disease.

This cross-sectional study tested the hypothesis that decreased serum levels of tetranectin (TN), a regulator of the fibrinolysis and proteolytic system, is associated with the presence and severity of CAD. We conducted a systematic serological and immunohistochemical (IHC) analysis to respectively compare the TN levels in serum and artery samples in CAD patients and healthy controls. Our results showed that serum levels of TN were significantly lower in patients with CAD than in healthy controls. Further analysis via trend tests revealed that serum TN levels correlated with the number of diseased arteries. Besides, the multivariate logistic regression model revealed TN as an independent factor associated with the presence of CAD. Additionally, IHC analysis showed that TN expression was significantly higher in atherosclerotic arteries as compared to healthy control tissues. In conclusion, our study suggests that increased serum TN level is associated with the presence and severity of diseased coronary arteries in patients with stable CAD.

Tetranectin gene deletion induces Parkinson's disease by enhancing neuronal apoptosis

Parkinson's disease (PD) is a chronic neurodegenerative disorder characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc). We previously identified tetranectin (TET) as a potential biomarker for PD whose expression is downregulated in the cerebrospinal fluid of PD patients. In the present study, we investigate the role of TET in neurodegeneration in vitro and in vivo. Our results showed that siRNA knockdown of TET decreased cell viability and the number of tyrosine hydroxylase (TH) positive cells, whereas it increased caspase-3 activity and the Bax/Bcl-2 ratio in cultured primary dopaminergic neurons. Overexpression of TET protected dopaminergic neurons against neuronal apoptosis in 1-methyl-4-phenylpyridinium cell culture model in vitro. In TET knockdown mouse model of PD, TET gene deletion decreased the number of TH positive cells in the SNpc, induced apoptosis via the p53/Bax pathway, and significantly impaired the motor behavior of transgenic mice. The findings suggest that TET plays a neuroprotective role via reducing neuron apoptosis and could be a valuable biomarker or potential therapeutic target for the treatment of patients with PD.

Tetranectin positive expression in tumour tissue leads to longer survival in Danish women with ovarian cancer. Results from the 'Malova' ovarian cancer study.

The primary objective of this study was to analyse Tetranectin (TN) expression in tumour tissues and TN serum concentration in 758 women with epithelial ovarian tumours. The second was to evaluate, whether TN tissue expression levels correlate with clinico-pathological parameters and prognosis of the disease. Using tissue arrays we analysed the expression levels in tissues from 166 women with borderline ovarian tumours (BOTs) and 592 women with ovarian cancer (OC). A panel of three antibodies was used for immunohistochemistry: a polyclonal and two monoclonal antibodies. Serum TN was measured using the polyclonal antibody A-371. Univariate survival analyses stratified for chemotherapy showed that positive tissue TN as demonstrated by the polyclonal antibody indicated a significantly longer overall survival (OS) (p = 0.0001) as well as cancer specific survival (CSS) (p < 0.0001). High serum TN was likewise found to imply longer OS (p < 0.0001) and CSS (p < 0.0001), whereas tissue staining with the two monoclonal antibodies failed to demonstrate any significant correlation with either survival type. Univariate Kaplan-Meier survival analysis performed on all OC cases showed a significantly longer OS (p = 0.0009) and CSS (p = 0.0006) for women with TN positive tumour tissue and in women with high serum TN levels (p < 0.0001 for both). However, in the multivariate Cox regression analysis, only serum TN was found to be an independent prognostic factor for OS (p = 0.01) and not for CSS (p = 0.08). In conclusion, our results predict that a positive TN expression of both tumour tissue and serum points to a more favourable outcome for OC patients.

Comparative analysis of serum proteomes: Identification of proteins associated with sciatica due to lumbar intervertebral disc herniation.

Lumbar intervertebral disc herniation (LDH) is one of the most common orthopedic conditions that can cause lower back pain and sciatica. However, the pathogenesis of LDH is poorly understood. The aim of the present study was to use proteomic analysis of blood samples to establish whether there are serum proteins associated with LDH, which may be useful in elucidating LDH pathogenesis. The ultimate aim was to develop a simple technique for the diagnosis of LDH based on the blood samples of patients with sciatica. The study used comparative analysis of serum proteomes associated with sciatica due to LDH. A total of 30 LDH patients with sciatica, receiving treatment between August and December 2007, were selected as the experimental group (or LDH group). A total of 2 ml of blood was obtained from each of the 30 patients in the LDH group and from 30 healthy volunteers, who constituted the control group. Two-dimensional electrophoresis of the blood samples was conducted, distinct protein spots were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and proteins associated with LDH were detected. An enzyme-linked immunosorbent assay (ELISA) was developed to screen for the LDH proteins and was tested on the sera of a second test and control group that included 10 patients with LDH and 10 healthy subjects, respectively. Based on signal intensity, the expression levels of 6 proteins on the dielectrophoretogram were found to be significantly associated with LDH. The identities of the LDH proteins were upregulated apolipoprotein-L1 (APO-L1) and two types of serum albumin precursors, and downregulated apolipoprotein M (APO-M), tetranectin (TN) and immunoglobulin light chain (IGL). Further ELISA experiments confirmed that there were increased serum levels of 4 out of the 6 proteins in patients with sciatica due to LDH, which was statistically different compared to the healthy subjects. In conclusion, these results suggest that serum APO-L1, TN, APO-M and IGL may serve as LDH biomarkers.

Tetranectin Promotes Adipogenesis and Lipogenesis and is Negatively Regulated by Polyunsaturated Fatty Acids in Human Adipocytes

Adipose tissues secrets factors, or adipokines, regulate body energy homeostasis. To search for novel adipokines, we employed 2‐D protein gel electropherosis and LC‐MS/MS to analyze human primary adipocyte culture medium, in which tetranectin (TN). We found that the mRNA expression of TN is positively correlated with the differentiation and lipid accumulation of human preadipocytes, as well as the body mass index. Overexpression and knockdown of TN in human primary adipocytes by lentivirus prove that TN increases the expression of adipogenic and lipogenic genes, such as peroxisome proliferator‐activated receptor gamma, lipoprotein lipase and fatty acid synthesis, but decreases those related to lipolysis, including hormone sensitive lipase, interleukin 6 and serum amyloid A along with altered profiles of proteins responsible primarily for lipid metabolism, as analyzed by quantitative proteomic analysis and quantitative real‐time PCR. In addition, treatments of polyunsaturated fatty acids (PUFA) suppressed TN expression. Taken together, our data suggest that not only TN potentially serves as a novel adipokine contributing to the regulation of energy homeostasis and lipid metabolism, but also components of the TN‐associated signaling pathways the therapeutic targets for treating obesity and associated metabolic diseases.

Research progress of tetranectin in tumors

Studies have shown that tetranectin is associated with many malignant tumors. Serum or plasma tetranectin levels may act as a useful prognostic marker in some malignant tumors. Tetranectin has been reported to play its role in tumors via binding to plasminogen. However, the mechanism remains to be elucidated. Key words: Connexins; Neoplasms; Research

The expression of tetranectin is affected by polyunsaturated fatty acids in human adipocytes

Tetranectin (TN) enhances fibrolysis specifically by binding to the plasminogen‐like hepatocyte growth factor and tissue‐type plasminogen activator (tPA). Tetranecttin is an inducer of plasminogen activation which is catalyzed by tPA. We detected the expression of TN in human adipocytes. Using the primers of TN exon1 to detect TN mRNA expression by real‐time PCR, we found that TN mRNA expression was positive correlated with both adipogenesis and human body mass index (BMI). Many genes involve in lipid metabolism is regulated by polyunsaturated fatty acids (PUFA) in adipocytes. PUFA also regulate the adipocyte differentiation, adipogenesis, and lipolysis. We treated human adipocytes with different PUFA, include docosahexaenoic acid, eicosapentaenoic acid, and arachinonic acid and found that PUFA decreased the expression of TN mRNA expression. These results suggest that TN may have a role related to regulating lipid metabolism in adipocytes.The project was funded in part by the National Science Council in Taiwan.Grant Funding Source: The project was funded in part by the National Science Council in Taiwan

Serum tetranectin as a preoperative indicator for postoperative complications in Danish ovarian cancer patients

Objective The association between tetranectin (TN) and selected lifestyle factors (smoking and alcohol) and the postoperative complication rate for ovarian cancer (OC) patients undergoing primary cytoreductive surgery has not yet been characterized. The aim of the study was to examine the value of TN, smoking and alcohol as indicators of postoperative complications in OC patients. Methods Serum TN was measured for 374 OC patients undergoing primary cytoreductive surgery. In addition, they reported their smoking and alcohol status. The prognostic value of variables was found with univariate and multivariate analyses using logistic regression analysis. Results In univariate analysis TN was the only one out of 8 variables that significantly predicted postoperative complications (OR = 0.55 (95% CI: 0.34–0.87), P = 0.01). High preoperative serum TN was associated with a low risk of postoperative complications. Stepwise reduction of the multivariate model demonstrated that TN and histology were the only significant co-variables (TN, OR = 0.51 (95% CI: 0.32–0.83), P = 0.006; histology, OR = 1.70 (95% CI: 1.02–2.82), P = 0.041). TN was the only indicator, which was statistical significant in both univariate and multivariate analyses. Conclusion Preoperative serum TN is a significant indicator of postoperative complications in Danish OC patients and deserves to be validated in larger future studies.

Serum tetranectin is a significant prognostic marker in ovarian cancer patients

To evaluate the prognostic value of preoperative serum tetranectin (TN) in Danish ovarian cancer (OvCa) patients. Design. Population-based, multidisciplinary Danish case-control study of OvCa. A total of 445 primary OvCa patients diagnosed at one of the gynecological departments in 18 regional hospitals around Denmark during the period 1994-1999. Serum levels of TN were evaluated preoperatively and tested for possible association with prognosis. Disease specific survival. During the observation period (median 45.9 months, range 0.2-121) 278 OvCa-related deaths were seen. Univariate analysis of TN and CA125 demonstrated a significant association with survival using the Cox proportional hazards model, when stratified for adjuvant treatment (TN: p < 0.0001, hazard ratio = 0.44; 95% confidence interval 0.33-0.60 and CA125: p < 0.0001, hazard ratio = 1.19; 95% confidence interval 1.11-1.27). Disease specific survival curves for patients with tumors in the early stages showed no significant association with survival, neither for TN (p = 0.68) nor for CA125 (p = 0.07). For the stage III group, a significant association with survival was found for TN (p = 0.027), but not for CA125 (p = 0.37). Multivariate Cox analysis identified TN, age, residual tumor, International Federation of Gynecology and Obstetrics stage and grade but not serum CA125 as independent prognostic variables. Preoperative serum TN is a useful prognostic indicator of advanced stage for patients with OvCa.

Tetranectin is a potential biomarker in cerebrospinal fluid and serum of patients with epilepsy

Background Tetranectin (TN) is a plasminogen kringle 4 binding protein and regulates fibrinolysis and proteolytic processes via binding to plasminogen. A previous proteomics study identified TN in the cerebrospinal fluid (CSF) of epileptic patients but not in healthy controls. We determined the concentrations of TN in CSF and serum of epileptic patients to evaluate the changes in TN levels after epileptic attack. Methods We detected TN in the CSF and serum of 64 epileptic patients and 26 healthy subjects using sandwich enzyme-linked immunosorbent assays. Results Compared with the control group, CSF-TN levels increased in epileptic patients while serum-TN levels decreased. These differences were statistically significant. The decrease of serum-TN in patients with drug-refractory epilepsy was the most striking. Conclusion CSF-TN and serum-TN are potential biomarkers in epilepsy and drug-refractory epilepsy and would be useful for diagnosis.

Alterations in biomarkers of endothelial function following on‐pump coronary artery revascularization

Cardiopulmonary bypass (CPB) has been associated with activation and injury of endothelial cells, probably responsible for the systemic inflammatory response syndrome (SIRS) taking place in these patients. We measured plasma concentrations of soluble P-selectin (sP-s), E-selectin (sE-s), tetranectin (TN), vonWillebrand factor (vWF) levels, and angiotensin-converting enzyme (ACE) activity in 31 adult patients undergoing elective coronary artery bypass grafting, just before and up to three days after surgery, and in 25 healthy volunteers. Patients showed higher plasma sP-s and sE-s and ACE concentrations, just before surgery, but significantly lower TN levels, compared with controls. During the first three postoperative days (PD), the concentration of each of the molecules followed a different and independent pattern, although in the third PD, the levels of sP-s, sE-s and ACE were higher and those of vWF and TN lower, compared with the preoperative ones. However, patients had higher sP-s (P=0.06), sE-s (P=0.07), and vWF (P=0.005), but lower TN concentrations (P=0.02) on the third PD compared with controls. CPB is characterised by pronounced changes in plasma sP-s, sE-s, TN, vWF levels, and ACE activity, which are associated with significant alteration in the intra- and early postoperative endothelial function observed in open heart surgery.

Preoperative serum tetranectin, CA125 and menopausal status used as single markers in screening and in a risk assessment index (RAI) in discriminating between benign and malignant ovarian tumors

Objectives To improve the poor survival in ovarian cancer (OC) patients, the research has been focused on new OC markers. One aim is to find markers to identify the cancers in early preclinical stages by screening. Another aim is to find new diagnostic markers, which may select patients at high risk for OC for quick referral to highly specialized centers in gynecologic oncology. These aims were addressed in the present study by evaluating serum tetranectin (TN) and serum CA125 on a large number of pre- and postmenopausal women with ovarian tumors and controls. Methods The potential ability of the markers to discriminate between the four groups (208 benign ovarian tumor, 153 borderline ovarian tumor (BOT), 445 OC and 1333 age matched controls) in OC screening was examined. We also constructed a risk assessment index (RAI) for discrimination between tumor groups based on these variables and menopausal status. Results Highly significant differences in both TN and CA125 levels were found between all the four groups as well as between the different FIGO stages of OC patients. A very high probability of having OC or a benign tumor, respectively, was predicted by the RAI. Conclusions In the case-control part of the study, we found that TN and CA125 deserve to be validated on pre-clinical samples by inclusion in future marker panels. The RAI is also a potential new candidate for a diagnostic tool for selecting patients at high risk for having OC; hence it deserves further evaluation in a prospective clinical study.