The Co-Expression of Estrogen Receptors ERα, ERß, and GPER in Endometrial Cancer.

Estrogens have important roles in endometrial cancer (EC) and exert biological effects through the classical estrogen receptors (ERs) ERα and ERß, and the G-protein-coupled ER, GPER. So far, the co-expression of these three types of ERs has not been studied in EC. We investigated ERα, ERß, GPER mRNA and protein levels, and their intracellular protein distributions in EC tissue and in adjacent control endometrial tissue. Compared to control endometrial tissue, immunoreactivity for ERα in EC tissue was weaker for nuclei with minor, but unchanged, cytoplasmic staining; mRNA and protein levels showed decreased patterns for ERα in EC tissue. For ERß, across both tissue types, the immunoreactivity was unchanged for nuclei and cytoplasm, although EC tissues again showed lower mRNA and protein levels compared to adjacent control endometrial tissue. The immunoreactivity of GPER as well as mRNA levels of GPER were unchanged across cancer and control endometrial tissues, while protein levels were lower in EC tissue. Statistically significant correlations of estrogen receptor α (ESR1) versus estrogen receptor ß (ESR2) and GPER variant 3,4 versus ESR1 and ESR2 was seen at the mRNA level. At the protein level studied with Western blotting, there was significant correlation of ERα versus GPER, and ERß versus GPER. While in clinical practice the expression of ERα is routinely tested in EC tissue, ERß and GPER need to be further studied to examine their potential as prognostic markers, provided that specific and validated antibodies are available.

Antibody Arrays Identified Cycle-Dependent Plasma Biomarker Candidates of Peritoneal Endometriosis.

Endometriosis is an estrogen-dependent inflammatory disease affecting women in their reproductive age. Due to non-specific symptoms, women with endometriosis are often misdiagnosed or are accurately diagnosed only after several years. Diagnosis of peritoneal endometriosis is especially challenging and relies only on laparoscopic surgery. To date, different molecules have been proposed as potential non-invasive biomarkers of endometriosis; however, none have been confirmed as clinically useful. Therefore, this study aimed to discover novel plasma biomarker candidates for peritoneal endometriosis using an antibody array platform. This study included patients with endometriosis-like symptoms characterized by the absence (controls) or presence of peritoneal endometriosis (cases) after laparoscopic surgery and histological evaluation. Patients were further divided into secretory and proliferative groups, according to the phase of their menstrual cycle. Their plasma samples were collected and analyzed on an antibody array platform targeting more than 1350 proteins with over 1820 antibodies. In the proliferative group, the analysis revealed three differential proteins between cases and controls: ITB3, ITA2B2, and ACVL-1. In the secretory group, none of the examined proteins reached the log-fold change (logFC) and significance thresholds simultaneously. The potential of the identified differential proteins as plasma biomarker candidates for peritoneal endometriosis should be evaluated on a larger cohort, and their role in endometriosis should be investigated in further studies.

Altered Profile of E1-S Transporters in Endometrial Cancer: Lower Protein Levels of ABCG2 and OSTß and Up-Regulation of SLCO1B3 Expression.

Endometrial cancer (EC) is associated with increased estrogen actions. Locally, estrogens can be formed from estrone-sulphate (E1-S) after cellular uptake by organic anion-transporting polypeptides (OATP) or organic anion transporters (OAT). Efflux of E1-S is enabled by ATP Binding Cassette transporters (ABC) and organic solute transporter (OST)αß. Currently, 19 E1-S transporters are known but their roles in EC are not yet understood. Here, we analysed levels of E1-S transporters in Ishikawa (premenopausal EC), HEC-1-A (postmenopausal EC), HIEEC (control) cell lines, in EC tissue, examined metabolism of steroid precursor E1-S, studied effects of OATPs' inhibition and gene-silencing on E1-S uptake, and assessed associations between transporters and histopathological data. Results revealed enhanced E1-S metabolism in HEC-1-A versus Ishikawa which could be explained by higher levels of OATPs in HEC-1-A versus Ishikawa, especially 6.3-fold up-regulation of OATP1B3 (SLCO1B3), as also confirmed by immunocytochemical staining and gene silencing studies, lower ABCG2 expression and higher levels of sulfatase (STS). In EC versus adjacent control tissue the highest differences were seen for ABCG2 and SLC51B (OSTß) which were 3.0-fold and 2.1-fold down-regulated, respectively. Immunohistochemistry confirmed lower levels of these two transporters in EC versus adjacent control tissue. Further analysis of histopathological data indicated that SLCO1B3 might be important for uptake of E1-S in tumours without lymphovascular invasion where it was 15.6-fold up-regulated as compared to adjacent control tissue. Our results clearly indicate the importance of E1-S transporters in EC pathophysiology and provide a base for further studies towards development of targeted treatment.

Tie-2, G-CSF, and Leptin as Promising Diagnostic Biomarkers for Endometrial Cancer: A Pilot Study.

Preoperative determination of the extent of endometrial cancer (EC) would avoid the complications associated with radical surgery. Screening of patients' plasma biomarkers might enable a more precise diagnosis of EC and a tailored treatment approach. This prospective case-control monocentric pilot study included 76 postmenopausal women (38 endometrioid EC patients and 38 control patients with benign gynecological conditions), and 37 angiogenic factors (AFs) were investigated as potential biomarkers for EC. AF concentrations in preoperative plasma samples were measured using Luminex xMAP™ multiplexing technology. The plasma levels of sTie-2 and G-CSF were significantly lower in EC compared to control patients, whereas the plasma levels of leptin were significantly higher in EC patients. Neuropilin-1 plasma levels were significantly higher in patients with type 2 EC (grade 3) compared to patients with lower grade cancer or controls. Follistatin levels were significantly higher in patients with lymphovascular invasion, and IL-8 plasma levels were significantly higher in patients with metastases. If validated, the plasma concentrations of the indicated AFs could represent an important additional diagnostic tool for the early detection and characterization of EC. This could guide the decision-making on the extent of surgery. Further studies with larger patient numbers are currently ongoing.

Multiplex analysis of 40 cytokines do not allow separation between endometriosis patients and controls.

Endometriosis is a common gynaecological condition characterized by severe pelvic pain and/or infertility. The combination of nonspecific symptoms and invasive laparoscopic diagnostics have prompted researchers to evaluate potential biomarkers that would enable a non-invasive diagnosis of endometriosis. Endometriosis is an inflammatory disease thus different cytokines represent potential diagnostic biomarkers. As panels of biomarkers are expected to enable better separation between patients and controls we evaluated 40 different cytokines in plasma samples of 210 patients (116 patients with endometriosis; 94 controls) from two medical centres (Slovenian, Austrian). Results of the univariate statistical analysis showed no differences in concentrations of the measured cytokines between patients and controls, confirmed by principal component analysis showing no clear separation amongst these two groups. In order to validate the hypothesis of a more profound (non-linear) differentiating dependency between features, machine learning methods were used. We trained four common machine learning algorithms (decision tree, linear model, k-nearest neighbour, random forest) on data from plasma levels of proteins and patients' clinical data. The constructed models, however, did not separate patients with endometriosis from the controls with sufficient sensitivity and specificity. This study thus indicates that plasma levels of the selected cytokines have limited potential for diagnosis of endometriosis.

Models including serum CA-125, BMI, cyst pathology, dysmenorrhea or dyspareunia for diagnosis of endometriosis.

AIM: To evaluate preoperative levels of CA-125 and HE4 in patients with endometriosis-like symptoms and to construct diagnostic models. PATIENTS: Prospective case-control study included 124 endometriosis patients and 97 control patients. MATERIALS & METHODS: Logistic regression was used to construct diagnostic models based on serum biomarker levels and clinical data. RESULTS: A model with CA-125, BMI, information on cysts and dyspareunia had an area under the curve value of 0.836, sensitivity of 74.0% and specificity of 81.3%. The second model included CA-125, BMI, information on cysts and dysmenorrhea and had an area under the curve value of 0.819, sensitivity of 74.8% and specificity of 79.2%. CONCLUSION: Constructed models have the potential for noninvasive diagnosis of endometriosis, and might be translated into clinical practice after additional validation.

Models including plasma levels of sphingomyelins and phosphatidylcholines as diagnostic and prognostic biomarkers of endometrial cancer.

In endometrial cancer, biomarkers for preoperative identification of patients with low risk for disease progression would enable stratification according to the extent of surgery needed, and would avoid the complications that can be associated with radical surgery. A panel of proteins, amino acids, enzymes, and miRNA has been investigated as potential biomarkers for endometrial cancer. At the time of the manuscript submission targeted metabolomics/lipidomics approaches have not been applied to biomarker research in endometrial cancer. Using electrospray ionization-tandem mass spectrometry we quantified 163 metabolites in 126 plasma samples (61 patients with endometrial cancer, 65 control patients). Three single phosphatidylcholines were identified with significantly decreased levels in patients with endometrial cancer. A diagnostic model was defined as the ratio between acylcarnitine C16 and phosphatidylcholine PCae C40:1, the ratio between proline and tyrosine, and the ratio between the two phosphatidylcholines PCaa C42:0 and PCae C44:5; which provided sensitivity of 85.25%, specificity of 69.23%, and AUC of 0.837. Addition of smoking status further improved the constructed diagnostic model (AUC = 0.855). The presence of the major prognostic factors of deep myometrial invasion and lymphovascular invasion were also associated with altered metabolite concentrations. A prognostic model for deep myometrial invasion included the ratio between two hydroxysphingomyelins SMOH C14:1 and SMOH C24:1, and the ratio between two phosphatidylcholines PCaa C40:2 and PCaa C42:6, which provided sensitivity of 81.25%, specificity of 86.36%, and AUC of 0.857. The model for lymphovascular invasion included the ratio between two phosphatidylcholines PCaa C34:4 and PCae C38:3, and the ratio between acylcarnitine C16:2 and phosphatidylcholine PCaa C38:1, which provided sensitivity of 88.89%, specificity of 84.31%, and AUC of 0.935.

Membrane progesterone receptors ß and γ have potential as prognostic biomarkers of endometrial cancer.

Endometrial cancer (EC) is one of the most common malignancies in women worldwide. EC is linked to chronic exposure to estrogens that is unopposed by protective effects of progesterone. Progesterone modulates gene expression via classical nuclear receptors, and has rapid effects via the less characterized membrane-bound progesterone receptors (mPRs) of the progestin and adipoQ receptor (PAQR) family. The presence of mPRs in EC has not been investigated to date. The aims of this study were to examine PAQR7, PAQR8 and PAQR5, which encode for mPRα, mPRß and mPRγ, respectively, for their expression and localization in EC tissue and adjacent control endometrium. Our results reveal decreased expression of PAQR7 and PAQR8, and unaltered expression of PAQR5 in EC versus control tissue. Expression of PAQR5 was decreased in EC with higher FIGO stage versus stage IA. Immunohistochemistry revealed lower levels of mPRα and mPRß, but higher levels of mPRγ, in EC versus control tissue. There was greater decrease in mPRß levels in tumors with lymphovascular invasion. The analysis of the expression data associates higher PAQR5 mRNA and mPRß protein levels with favorable patient prognosis. Immunohistochemistry showed diverse localizations of mPRs in control and cancer endometrium. In control endometrium, mPRα and mPRß were localized mostly at the cell membranes, while mPRγ was localized in the cytoplasm and/or nucleus. In cancer endometrium, mPRα and mPRß were detected at the cell membrane or in the cytoplasm, or both, while mPRγ was only localized in the cytoplasm. Taken together, these results imply that mPRs are involved in EC pathogenesis through effects on the development or progression of cancer. The potential role of mPRß and mPRγ as prognostic biomarkers needs to be further assessed on a larger number of samples.

Detection of Aristaless-related homeobox protein in ovarian sex cord-stromal tumors.

OBJECTIVE: To examine the potential of ARX as a novel biomarker of ovarian endometriosis and other ovarian pathologies. METHODS: The mRNA level of ARX in ovarian endometriosis and normal endometrium samples was determined by real-time PCR, while the protein level was determined by Western blotting and immunohistochemical staining. Immunohistochemical analysis was performed on nearly 200 tissue samples of different ovarian pathologies. GraphPad Prism was used for statistical analysis. RESULTS: The expression of ARX was significantly increased in ovarian endometriosis samples as compared to normal endometrium. Also Western blotting data showed higher ARX levels in the ovarian endometriosis samples versus normal endometrium. Immunohistochemical analysis revealed that the protein is localized in the ovarian stroma and does not originate from endometriosis. Further immunohistochemical analysis performed on several different non-neoplastic and neoplastic ovarian tissue samples revealed that in the non-neoplastic ovary ARX protein is present only in the stromal cells and their derivates (luteinized stromal cells, theca and Leydig cells) and not in granulosa cells, oocites, surface epithelium or rete ovarii, while all stromal and sex cord tumors showed strong nuclear staining for ARX. All other primary or metastatic epithelial tumors of the ovary were ARX negative. CONCLUSIONS: ARX is not associated with endometriosis and cannot be used as a biomarker for ovarian endometriosis. ARX is present in ovarian stroma and cells derived from ovarian stroma as well as in all types of sex cord-stromal tumors of the ovary and could thus be used as a marker for sex cord-stromal differentiation in ovarian tumors.

Novel algorithm including CA-125, HE4 and body mass index in the diagnosis of endometrial cancer.

OBJECTIVES: To evaluate the diagnostic and prognostic potential of preoperative serum CA-125 and HE4 levels in patients with endometrial cancer. METHODS: Prospective case-control study of 133 women who underwent surgical treatment at the University Medical Centre Ljubljana (64 patients with endometrial cancer, 69 control patients with prolapsed uterus or myoma). Serum CA-125 and HE4 levels were determined using electrochemiluminescent assays. RESULTS: Serum CA-125 and HE4 levels were significantly higher in patients with endometrial cancer, compared to the controls (p=2.67×10-4, 1.36×10-7, respectively). A diagnostic model that combines serum CA-125 and HE4 levels and body mass index separated patients with endometrial cancer from controls, with AUC of 0.804, sensitivity of 66.7%, and specificity of 84.6%. Serum HE4 levels showed good prognostic potential and stratified the patients according to presence/absence of deep myometrial invasion (p=0.001) or lymphovascular invasion (p=0.003), with AUCs of 0.78 and 0.81, respectively. In low-risk patients with grade 1 and 2 endometrioid cancer for whom lymphadenectomy can be avoided, HE4 allowed stratification according to deep myometrial invasion (p=3.39×10-4), with AUC of 0.84. Although median HE4 levels were higher in patients with lymphovascular invasion, this difference did not reach significance (p=0.06). CONCLUSIONS: A model based on preoperative serum CA-125 and HE4 levels and body mass index has good diagnostic accuracy for separation of patients with endometrial cancer and control patients. In patients with endometrial cancer, serum HE4 levels allow prediction of deep myometrial and lymphovascular invasion.

The Significance of the Sulfatase Pathway for Local Estrogen Formation in Endometrial Cancer.

Endometrial cancer (EC) is the most common estrogen-dependent gynecological malignancy in the developed World. To investigate the local formation of estradiol (E2), we first measured the concentrations of the steroid precursor androstenedione (A-dione) and the most potent estrogen, E2, and we evaluated the metabolism of A-dione, estrone-sulfate (E1-S), and estrone (E1) in cancerous and adjacent control endometrium. Furthermore, we studied expression of the key genes for estradiol formation via the aromatase and sulfatase pathways. A-dione and E2 were detected in cancerous and adjacent control endometrium. In cancerous endometrium, A-dione was metabolized to testosterone, and no E2 was formed. Both, E1-S and E1 were metabolized to E2, with increased levels of E2 seen in cancerous tissue. There was no significant difference in expression of the key genes of the aromatase (CYP19A1) and the sulfatase (STS, HSD17B1, HSD17B2) pathways in cancerous endometrium compared to adjacent control tissue. The mRNA levels of CYP19A1 and HSD17B1 were low, and HSD17B14, which promotes inactivation of E2, was significantly down-regulated in cancerous endometrium, especially in patients with lymphovascular invasion. At the protein level, there were no differences in the levels of STS and HSD17B2 between cancerous and adjacent control tissue by Western blotting, and immunohistochemistry revealed intense staining for STS and HSD17B2, and weak staining for SULT1E1 and HSD17B1 in cancerous tissue. Our data demonstrate that in cancerous endometrium, E2 is formed from E1-S via the sulfatase pathway, and not from A-dione via the aromatase pathway.