Lubos Minar

Simplified protocol for flow cytometry analysis of fluorescently labeled exosomes and microvesicles using dedicated flow cytometer

Flow cytometry is a powerful method, which is widely used for high-throughput quantitative and qualitative analysis of cells. However, its straightforward applicability for extracellular vesicles (EVs) and mainly exosomes is hampered by several challenges, reflecting mostly the small size of these vesicles (exosomes: ~80–200 nm, microvesicles: ~200–1,000 nm), their polydispersity, and low refractive index. The current best and most widely used protocol for beads-free flow cytometry of exosomes uses ultracentrifugation (UC) coupled with floatation in sucrose gradient for their isolation, labeling with lipophilic dye PKH67 and antibodies, and an optimized version of commercial high-end cytometer for analysis. However, this approach requires an experienced flow cytometer operator capable of manual hardware adjustments and calibration of the cytometer. Here, we provide a novel and fast approach for quantification and characterization of both exosomes and microvesicles isolated from cell culture media as well as from more complex human samples (ascites of ovarian cancer patients) suitable for multiuser labs by using a flow cytometer especially designed for small particles, which can be used without adjustments prior to data acquisition. EVs can be fluorescently labeled with protein-(Carboxyfluoresceinsuccinimidyl ester, CFSE) and/or lipid- (FM) specific dyes, without the necessity of removing the unbound fluorescent dye by UC, which further facilitates and speeds up the characterization of microvesicles and exosomes using flow cytometry. In addition, double labeling with protein- and lipid-specific dyes enables separation of EVs from common contaminants of EV preparations, such as protein aggregates or micelles formed by unbound lipophilic styryl dyes, thus not leading to overestimation of EV numbers. Moreover, our protocol is compatible with antibody labeling using fluorescently conjugated primary antibodies. The presented methodology opens the possibility for routine quantification and characterization of EVs from various sources. Finally, it has the potential to bring a desired level of control into routine experiments and non-specialized labs, thanks to its simple bead-based standardization.

L1CAM expression in endometrial carcinomas: an ENITEC collaboration study

Background:Identification of aggressive endometrioid endometrial carcinomas (EECs) and non-endometrioid carcinomas (NEECs) is essential to improve outcome. L1 cell adhesion molecule (L1CAM) expression is a strong prognostic marker in stage I EECs, but less is known about L1CAM expression in advanced-stage EECs and NEECs. This study analyses L1CAM expression in a clinically representative cohort of endometrial carcinomas.Methods:The expression of L1CAM was immunohistochemically determined in 1199 endometrial carcinomas, treated at one of the European Network for Individualized Treatment of Endometrial Cancer (ENITEC) centres. Staining was considered positive when >10% of the tumour cells expressed L1CAM. The association between L1CAM expression and several clincopathological characteristics and disease outcome was calculated.Results:In all, L1CAM was expressed in 10% of the 935 stage I EECs, 18% of the 160 advanced stage EECs, and 75% of the 104 NEECs. The expression of L1CAM was associated with advanced stage, nodal involvement, high tumour grade, non-endometrioid histology, lymphovascular space invasion, and distant recurrences in all cases, and with reduced survival in the EECs, but not in the NEECs.Conclusions:The expression of L1CAM is a strong predictor of poor outcome in EECs, but not NEECs. It is strongly associated with non-endometrioid histology and distant spread, and could improve the postoperative selection of high-risk endometrial carcinomas. The value of L1CAM expression in the preoperative selection of high-risk endometrial carcinomas should be studied.

Prognostic value of human epididymis protein 4 in endometrial cancer and its utility for surgical staging

An optimal surgical staging in the group of patients with the high‐risk type of endometrial cancer is often limited by age and serious internal comorbidities. Therefore, in this study we focused on human epididymis protein 4 and its contribution to the preoperative differentiation of prognostically distinct groups of patients and to individualized surgical treatment as compared with cancer antigen (CA) 125 and imaging methods.

Added Value of Estrogen Receptor, Progesterone Receptor, and L1 Cell Adhesion Molecule Expression to Histology-Based Endometrial Carcinoma Recurrence Prediction Models: An ENITEC Collaboration Study

Objectives Endometrial carcinoma mortality is mainly caused by recurrent disease, and various immunohistochemical markers to predict recurrences have been studied. Loss of the estrogen receptor (ER) and progesterone receptor (PR) and the presence of the L1 cell adhesion molecule (L1CAM) are promising markers, but their combined value has not been studied. Materials and Methods Expression of ER, PR, and L1CAM was immunohistochemically determined in 293 endometrial carcinomas from 11 collaborating European Network for Individualized Treatment of Endometrial Cancer centers. Estrogen receptor, PR, or L1CAM staining was considered positive or negative when expressed by greater than or equal to 10% or less than 10% of the tumor cells, respectively. The association between these markers and clinicopathological markers, and their combined value in predicting survival were calculated, both in the entire cohort and in a selected groups of stage I endometrioid and low-risk stage I endometrioid carcinomas. Results Estrogen receptor and PR were negative in 19% and 28% of the cases, respectively, and L1CAM was positive in 18%. All 3 were associated with advanced stage, high-grade, nonendometrioid histology, lymphovascular space invasion (LVSI), and reduced disease-free survival. Only advanced stage, loss of PR, and LVSI were associated with reduced disease-free survival in multivariate analysis. A prognostic model including these 3 markers was superior to 1 including only the 3 immunohistochemical markers, which was superior to the traditional model. In both the stage I endometrioid and the low-risk stage I endometrioid groups, only loss of PR was associated with reduced disease-free survival. Conclusions Loss of ER and PR, and the presence of L1CAM are associated with high risk characteristics, and loss of PR is the strongest predictor of recurrent disease. Although a combination of these 3 markers is slightly superior to the traditional histological markers, a prognostic model including stage, PR expression, and LVSI is the most promising model in the identification of high risk carcinomas. In the stage I endometrioid carcinomas, PR immunohistochemistry appears to be of additional value in predicting recurrences.

Comparison of the Copenhagen Index versus ROMA for the preoperative assessment of women with ovarian tumors

To compare the Copenhagen Index (CPH‐I) and the Risk of Ovarian Malignancy Algorithm (ROMA) in the differential diagnosis of ovarian tumors.

Secondary cytoreductive surgery - viable treatment option in the management of platinum-sensitive recurrent ovarian cancer

OBJECTIVE This study aimed to evaluate the impact of the secondary cytoreductive surgery on survival parameters in women with platinum-sensitive recurrent ovarian cancer who undergone secondary cytoreduction following chemotherapy compared to women who recieved chemotherapy alone. STUDY DESIGN In a retrospective study, data were rewieved from women who were diagnosed and treated with ovarian cancer and its primary platinum-sensitive recurrence at the University Hospital Brno in the Czech Republic between November 2009 and March 2016. Out of the total number of 62 patients with recurrence, 30 women underwent cytoreductive surgery plus chemotherapy and 32 were treated with chemotherapy alone. The good performance status expressed by ECOG score 0-1, the single site of recurrence regardless of platinum-free interval or multiple sites of recurrence but no carcinomatosis and platinum-free interval >12 months, and no or small-volume ascites (<500 ml) were considered inclusion criteria for cytoreductive surgery. Women not meeting these criteria were treated by chemotherapy alone. Descriptive statistics, Kaplan-Meier survival curves and Log-Rank test were used for statistical estimations. RESULTS The analysis confirmed more favorable prognosis in patient group treated with a combination secondary cytoreduction and chemotherapy. Mean disease-free survival (DFS) was 49.8 months (95% CI; 33.2-66.3) and mean overall survival (OS) stood at 54.0 months (95% CI; 39.4-68.6) in this patient cohort, while in patient group treated with chemotherapy alone it was found that mean DFS was 16.6 months (95% CI; 7.4-25.8) and mean OS stood at 26.2 months (95% CI; 16.6-35.8). When testing the difference between survival curves, statistically significant differences were observed in both DFS (p = 0.010) and OS (p = 0.007) rates between two treatment groups. Age < 60 years at the time of recurrence and zero macroscopic residual disease after secondary cytoreduction were identified as favorable prognostic factors for both DFS and OS in a multivariate analysis. CONCLUSION Secondary cytoreductive surgery is acceptable as a viable treatment option for highly selected women with ovarian cancer recurrence. Complete resection is considered ultimate goal of secondary cytoreduction on condition that the balance between maximal survival gain and minimal operative morbidity will be kept.

Cell-Free Urinary MicroRNAs Expression in Small-Scale Experiments

Cell-free microRNAs (miRNAs) have become one of the novel promising diagnostic and prognostic biomarkers for various diseases recently. Blood serum and plasma along with urine are the most common sources of clinically well, almost noninvasively available samples containing various types of miRNAs. Here, we present a protocol for a small-scale study investigating expression of several candidate miRNAs. Small-scale experiments may be worth investigating in cases where no information is available on miRNAs expression in particular diseases, for validation of previously published miRNAs with promising diagnostic potential, particularly in situations where follow-up study is aimed at validating miRNAs coming from array or NGS experiments, or where funding for these large-scale experiments is not available.Using urine miRNAs expression as the novel diagnostic tools is challenging and currently this approach is still in its infancy. Therefore, various methods may result in different conclusions depending on clinical sample sets and differences among methods used for the miRNAs isolation and quantitation. In this protocol, we present the method evaluated in the study focused on cell-free urinary miRNAs in ovarian and endometrial cancers. We recommend using stabilization tubes for the urine collection, as this step may be necessary to stop activity of RNases. Further, routine real-time PCR methods are described. We demonstrate that assessment of urinary miRNAs expression may reveal as a feasible method to explore the potential for finding novel diagnostic and prognostic markers.

Modified posterior pelvic exenteration for advanced ovarian malignancies: a single-institution study of 35 cases

This study aimed to investigate the possible benefits of a complete cytoreduction in patients with advanced ovarian cancer and concomitant rectal invasion. Furthermore, we evaluated the morbidity associated with radical surgery.