Benchmarking blood collection tubes and processing intervals for extracellular vesicle performance metrics.

The analysis of extracellular vesicles (EV) in blood samples is under intense investigation and holds the potential to deliver clinically meaningful biomarkers for health and disease. Technical variation must be minimized to confidently assess EV-associated biomarkers, but the impact of pre-analytics on EV characteristics in blood samples remains minimally explored. We present the results from the first large-scale EV Blood Benchmarking (EVBB) study in which we systematically compared 11 blood collection tubes (BCT; six preservation and five non-preservation) and three blood processing intervals (BPI; 1, 8 and 72 h) on defined performance metrics (n = 9). The EVBB study identifies a significant impact of multiple BCT and BPI on a diverse set of metrics reflecting blood sample quality, ex-vivo generation of blood-cell derived EV, EV recovery and EV-associated molecular signatures. The results assist the informed selection of the optimal BCT and BPI for EV analysis. The proposed metrics serve as a framework to guide future research on pre-analytics and further support methodological standardization of EV studies.

Multicentre, prospective study on local treatment of metastatic prostate cancer (LoMP study).

OBJECTIVES: To investigate the role of cytoreductive radical prostatectomy in addition to standard of care for patients with newly diagnosed metastatic prostate cancer. MATERIALS AND METHODS: This multicentre, prospective study included asymptomatic patients from 2014 to 2018 (NCT02138721). Cytoreductive radical prostatectomy was offered to all fit patients with resectable tumours, resulting in 40 patients. Standard of care was administered to 40 patients who were ineligible or unwilling to undergo surgery. The primary endpoint was castration resistant cancer-free survival at the time point of ≥50% events. The secondary endpoint was local event-free survival. Kaplan-Meier and Cox regression analyses with propensity-score analysis were applied. RESULTS: After a median (quartiles) follow-up of 35 (24-47) months, 42 patients became castration-resistant or died. The median castration resistant cancer-free survival was 53 (95% confidence interval [CI] 14-92) vs 21 (95% CI 15-27) months for cytoreductive radical prostatectomy compared to standard of care (P = 0.017). The 3-year estimates for local event-free survival were 83% (95% CI 71-95) vs 59% (95% CI 51-67) for cytoreductive radical prostatectomy compared to standard of care (P = 0.012). However, treatment group showed no significance in the multivariable models for castration resistant cancer-free survival (P = 0.5) or local event-free survival (P = 0.3), adjusted for propensity-score analysis. Complications were similar to the non-metastatic setting. Patients undergoing surgery were younger, with lower baseline prostate-specific antigen levels, alkaline phosphatase levels and metastatic burden. CONCLUSION: The present LoMP study was unable to show a difference between the two inclusion groups regarding castration resistant cancer-free survival for asymptomatic patients with newly diagnosed metastatic prostate cancer. These results validate previous evidence that, in well-selected and informed patients, cytoreductive radical prostatectomy is feasible and safe, with corresponding continence rates compared to the non-metastatic, high-risk setting. Whether cytoreductive radical prostatectomy could be a valuable option to achieve good local palliation needs to be further researched. Overall, the role of cytoreductive radical prostatectomy needs to be further explored in randomized studies to correct for potential bias.

Detection of bladder cancer with aberrantly fucosylated ITGA3.

We describe a simple, non-invasive assay to identify fucosylated-glycoisoform of integrin alpha-3 (ITGA3) directly from unprocessed urine. ITGA3 was detected directly from the urine of bladder cancer (BlCa) (n = 13) and benign prostatic hyperplasia (BPH) (n = 9) patients with the use of lectins coated on europium-doped-nanoparticles (Eu3+-NPs). Lectin Ulex europaeus agglutinin-I (UEA) showed enhanced binding with BlCa-derived ITGA3. The evaluation with individual samples showed that a glycovariant ITGA3-UEA assay could significantly discriminate BlCa from BPH patients (p = 0.007). The detection of aberrantly fucosylated-isoform of ITGA3 from urine can be used to distinguish BlCa from age-matched benign controls in a simple sandwich assay.

Unravelling the proteomic landscape of extracellular vesicles in prostate cancer by density-based fractionation of urine.

Extracellular vesicles (EV) are increasingly being recognized as important vehicles of intercellular communication and promising diagnostic and prognostic biomarkers in cancer. Despite this enormous clinical potential, the plethora of methods to separate EV from biofluids, providing material of highly variable purity, and lacking knowledge regarding methodological repeatability pose a barrier to clinical translation. Urine is considered an ideal proximal fluid for the study of EV in urological cancers due to its direct contact with the urogenital system. We demonstrate that density-based fractionation of urine by bottom-up Optiprep density gradient centrifugation separates EV and soluble proteins with high specificity and repeatability. Mass spectrometry-based proteomic analysis of urinary EV (uEV) in men with benign and malignant prostate disease allowed us to significantly expand the known human uEV proteome with high specificity and identifies a unique biological profile in prostate cancer not uncovered by the analysis of soluble proteins. In addition, profiling the proteome of EV separated from prostate tumour conditioned medium and matched uEV confirms the specificity of the identified uEV proteome for prostate cancer. Finally, a comparative proteomic analysis with uEV from patients with bladder and renal cancer provided additional evidence of the selective enrichment of protein signatures in uEV reflecting their respective cancer tissues of origin. In conclusion, this study identifies hundreds of previously undetected proteins in uEV of prostate cancer patients and provides a powerful toolbox to map uEV content and contaminants ultimately allowing biomarker discovery in urological cancers.

Abiraterone and spironolactone in prostate cancer: a combination to avoid.

Objectives: Disease progression in metastatic castration-resistant prostate cancer (mCRPC) is dependent on androgen signaling. This case describes the complex adaptive androgen signaling mechanisms in mCRPC and illustrates that caution should be exercised when treating these patients with drugs influencing the androgen axis.Methods: Single case report and review of the literature.Results: We report the case of an 86-year-old man with mCRPC, treated with the secondary antihormonal agent abiraterone acetate. Following association of spironolactone to deal with symptoms related to mineralocorticoid excess, biochemical and radiographic disease progression occurred. Spironolactone was discontinued and 8 months after withdrawal, the patient continues to show a biochemical response to abiraterone.Conclusions: Although spironolactone generally exerts anti-androgenic effects, experimental evidence exists that it acts as an androgen receptor agonist in an androgen-depleted environment, capable of inducing prostate cancer proliferation. This is supported by the observations described in this case report. Therefore, spironolactone should be avoided in prostate cancer patients suffering from treatment-associated side effects of abiraterone.

Importance of metastatic volume in prognostic models to predict survival in newly diagnosed metastatic prostate cancer.

PURPOSE: To explore the prognostic importance of metastatic volume in a contemporary daily practice cohort of patients with newly diagnosed metastatic hormone-naive prostate cancer (mHNPC) and to develop a pragmatic prognostic model to predict survival for these patients. METHODS: Since 2014, 113 patients with newly diagnosed mHNPC were prospectively registered. Statistical analysis was performed using SPSS 25.0™ with two-sided p value < 0.05 indicating statistical significance. Univariate and multivariate cox regression analyses were performed to identify prognostic risk factors. Kaplan-Meier method with log-rank statistics was constructed to analyze difference in survival in the prognostic groups. Model performance was assessed using the Concordance-index (C-index) and cross-validated in R v3.4.1. High-volume mHNPC (HVD) was defined as the presence of visceral metastasis or ≥ 4 bone metastases with ≥ 1 appendicular lesion. RESULTS: Multivariate analysis identified HVD (p = 0.047) and elevated alkaline phosphatase (ALP) (p = 0.018) as independent prognostic risk factors for overall survival (OS). Consequently, three prognostic groups were created: a good (no risk factors), intermediate (1 risk factor) and poor prognosis group (2 risk factors). Median OS for the good, intermediate and poor prognosis group was not reached, 73 and 20 months (95% CI 9-31 months with p < 0.001 and Correspondence-index of 0.78), respectively. CONCLUSIONS: We developed a pragmatic and qualitative prognostic model consisting of three prognostic risk groups for OS in a daily practice cohort of patients with newly diagnosed mHNPC. Independent prognostic risk factors included in the model were HVD and abnormal ALP.

Discovery and validation of a serum microRNA signature to characterize oligo- and polymetastatic prostate cancer: not ready for prime time.

PURPOSE: Patients with oligometastatic prostate cancer (PC) may benefit from metastasis-directed therapy (MDT), delaying disease progression and the start of palliative systemic treatment. However, a significant proportion of oligometastatic PC patients progress to polymetastatic PC within a year following MDT, suggesting an underestimation of the metastatic load by current staging modalities. Molecular markers could help to identify true oligometastatic patients eligible for MDT. METHODS: Patients with asymptomatic biochemical recurrence following primary PC treatment were classified as oligo- or polymetastatic based on 18F-choline PET/CT imaging. Oligometastatic patients had up to three metastases at baseline and did not progress to more than three lesions following MDT or surveillance within 1 year of diagnosis of metastases. Polymetastatic patients had > 3 metastases at baseline or developed > 3 metastases within 1 year following imaging. A model aiming to prospectively distinguish oligo- and polymetastatic PC patients was trained using clinicopathological parameters and serum-derived microRNA expression profiles from a discovery cohort of 20 oligometastatic and 20 polymetastatic PC patients. To confirm the models predictive performance, it was applied on biomarker data obtained from an independent validation cohort of 44 patients with oligometastatic and 39 patients with polymetastatic disease. RESULTS: Oligometastatic PC patients had a more favorable prognosis compared to polymetastatic ones, as defined by a significantly longer median CRPC-free survival (not reached versus 38 months; 95% confidence interval 31-45 months with P < 0.001). Despite the good performance of a predictive model trained on the discovery cohort, with an AUC of 0.833 (0.693-0.973; 95% CI) and a sensitivity of 0.894 (0.714-1.000; 95% CI) for oligometastatic disease, none of the miRNA targets were found to be differentially expressed between oligo- and polymetastatic PC patients in the signature validation cohort. The multivariate model had an AUC of 0.393 (0.534 after cross-validation) and therefore, no predictive ability. CONCLUSIONS: Although PC patients with oligometastatic disease had a more favorable prognosis, no serum-derived biomarkers allowing for prospective discrimination of oligo- and polymetastatic prostate cancer patients could be identified.

Urinary extracellular vesicle biomarkers in urological cancers: From discovery towards clinical implementation.

Urine contains cellular elements, biochemicals, and proteins derived from glomerular filtration of plasma, renal tubule excretion, and urogenital tract secretions that reflect an individual's metabolic and pathophysiologic state. Despite intensive research into the discovery of urinary biomarkers to facilitate early diagnosis, accurate prognosis and prediction of therapy response in urological cancers, none of these markers has reached widespread use. Their implementation into daily clinical practice is hampered by a substantial degree of heterogeneity in performance characteristics and uncertainty about reliability, clinical utility and cost-effectiveness, in addition to several technical limitations. Extracellular vesicles (EV) have raised interest as a potential source of biomarker discovery because of their role in intercellular communication and the resemblance of their molecular content to that of the releasing cells. We review currently used urinary biomarkers in the clinic and attempts that have been made to identify EV-derived biomarkers for urological cancers. In addition, we discuss technical and methodological considerations towards their clinical implementation.

Metastatic burden in newly diagnosed hormone-naive metastatic prostate cancer: Comparing definitions of CHAARTED and LATITUDE trial.

OBJECTIVES: No uniformity exists in the definition of metastatic burden in metastatic hormone-naive prostate cancer (mHNPC) across clinical trials making their comparison challenging. We explored definition agreement and prognostic significance of bulky mHNPC according to the CHAARTED and LATITUDE trial. MATERIALS AND METHODS: Since 2014, 95 patients with newly diagnosed mHNPC were prospectively registered. For this study, they were categorized as having high-volume (HVD) vs. low-volume (LVD) and high-risk (HRD) vs. low-risk disease (LRD) according to the definition of CHAARTED and LATITUDE, respectively. Agreement was tested using Cohen's κ coefficient. The Kaplan-Meier method was used to compare castration-resistant prostate cancer-free survival (CRPC-FS) and overall survival (OS). Prognostic significance was analyzed using Cox regression models. RESULTS: In total, 44 (46%) and 46 (48%) patients showed HVD and HRD, respectively. Cohen's κ coefficient was 0.83 indicating "almost perfect" agreement (P<0.001). Median CRPC-FS was 40 (95% CI: 25-55) vs. 11 months (95% CI: 8-14) for LVD and HVD (P = 0.001); 40 (95% CI: 27-53) vs. 11 months (95% CI: 8-14) for LRD and HRD (P<0.001), respectively. Median OS was not reached vs. 51 months (95% CI: 0-102) for LVD and HVD (P = 0.001); not reached vs. 51 months (95% CI: 2-100) for LRD and HRD (P = 0.003), respectively. The prognostic significance of both definitions remained significant in the multivariate model for CRPC-FS (P = 0.012 and P = 0.003). CONCLUSIONS: There is an excellent agreement between the definitions of bulky mHNPC in the CHAARTED and LATITUDE trial. Both definitions have significant prognostic value for predicting worse CRPC-FS and OS.

Prognostic and Therapeutic Implications of Circulating Androgen Receptor Gene Copy Number in Prostate Cancer Patients Using Droplet Digital Polymerase Chain Reaction.

BACKGROUND: Resistance mechanisms in the androgen receptor (AR) signaling pathway remain key drivers in the progression to castration-resistant prostate cancer (CRPC) and relapse under antihormonal therapy. MATERIALS AND METHODS: We evaluated the circulating AR gene copy number (CN) gain using droplet digital polymerase chain reaction in 21 control and 91 prostate cancer serum samples and its prognostic and therapeutic implications in prostate cancer. RESULTS: In CRPC, AR CN gain was associated with faster progression to CRPC (P = .026), a greater number of previous treatments (P = .045), and previous chemotherapy (P = .016). Comparing patients with and without CN gain, the median progression-free survival (PFS) in the abiraterone subgroup was 1.7 months versus not reached (P = .004), and the median overall survival (OS) was 7 months versus 20.9 months (P = .020). In the enzalutamide subgroup, PFS was 1.7 versus 10.8 months (P = .006), and OS was 6.1 versus 16.5 months (P = .042). In the taxane subgroup, PFS was 3.2 versus 6.5 months (P = .093), and OS was 3.9 months versus not reached (P = .026). The presence of more AR copies correlated with shorter androgen deprivation (P = .002), abiraterone (P = .022), enzalutamide (P = .008), and taxane (P = .039) therapy. CONCLUSION: Circulating AR CN gain predicts for a poor prognosis in CRPC. It is a promising biomarker predetermining rapid CRPC progression and predicting worse abiraterone and enzalutamide outcomes. Furthermore, it is associated with multiple previous treatments and previous chemotherapy.

Confounding factors of ultrafiltration and protein analysis in extracellular vesicle research.

Identification and validation of extracellular vesicle (EV)-associated biomarkers requires robust isolation and characterization protocols. We assessed the impact of some commonly implemented pre-analytical, analytical and post-analytical variables in EV research. Centrifugal filters with different membrane types and pore sizes are used to reduce large volume biofluids prior to EV isolation or to concentrate EVs. We compared five commonly reported filters for their efficiency when using plasma, urine and EV-spiked PBS. Regenerated cellulose membranes with pore size of 10 kDa recovered EVs the most efficient. Less than 40% recovery was achieved with other filters. Next, we analyzed the effect of the type of protein assays to measure EV protein in colorimetric and fluorometric kits. The fluorometric assay Qubit measured low concentration EV and BSA samples the most accurately with the lowest variation among technical and biological replicates. Lastly, we quantified Optiprep remnants in EV samples from density gradient ultracentrifugation and demonstrate that size-exclusion chromatography efficiently removes Optiprep from EVs. In conclusion, choice of centrifugal filters and protein assays confound EV analysis and should be carefully considered to increase efficiency towards biomarker discovery. SEC-based removal of Optiprep remnants from EVs can be considered for downstream applications.

Whole pelvis radiotherapy for pathological node-positive prostate cancer : Oncological outcome and prognostic factors.

PURPOSE: The goal of this work was to investigate the oncological outcome of whole pelvis radiotherapy (wpRT) in pathologic pelvic lymph node-positive (pN1) prostate cancer (PCa), evaluate the location of relapse, and identify potential prognostic factors. PATIENTS AND METHODS: All patients undergoing pelvic lymph node dissection (PLND) since the year 2000 at a single tertiary care center were evaluated. A total of 154 patients with pN1 PCa were treated with wpRT (39 in an adjuvant setting) and 2-3 years of androgen deprivation therapy (ADT). Kaplan-Meier analysis was performed to estimate biochemical recurrence-free survival (bRFS), clinical progression-free survival (cPFS), and prostate cancer-specific survival (CSS). Uni- and multivariate regression analyses were performed to identify prognostic factors. RESULTS: Estimated bRFS was 67%, cPFS was 71%, and CSS was 96% at 5 years. Median follow-up was 55 months (interquartile range 25-87). Multivariate analysis identified having only 1 positive lymph node, a shorter time between diagnosis and PLND, and older age as independent favorable prognostic factors for biochemical and clinical recurrence. The number of positive lymph nodes was prognostic for CSS (hazard ratio [HR] 1.34, 95% confidence interval 1.17-1.54) and OS (HR 1.22, 95% confidence interval 1.10-1.36). Bone metastases were the most frequent location of PCa relapse (n = 32, 64%). CONCLUSIONS: Patients with pN1 PCa treated with wpRT and 2-3 years ADT have an encouraging 5­year CSS. Understaging of the disease extent may be the most important enemy in definitive pN1 PCa treatment.

Function of extracellular vesicle-associated miRNAs in metastasis.

Extracellular RNA (exRNA) is functionally transferrable from donor to recipient cells and is protected from RNAses by electrostatic interactions with proteins or by membrane encapsulation. In addition to bioactive RNA, extracellular vesicles (EVs) contain intraluminal and membrane-associated proteins. The cellular context and fitness affect the composition of EVs and thus the outcome of the communication between the EV-producer and recipient cells. Adaptive communication through EVs is particularly important between cancer cells and their local and distant environment and drives life-threatening metastatic progression. Small noncoding RNAs (miRNAs) have been reported in EV isolations and play a role in local invasion, angiogenesis, immune modulation, metastatic niche preparation, colonization and dormancy. The metastasis-related functions attributed to EV-associated miRNAs are currently increasing exponentially in the scientific literature. We must be aware that the correct and efficient separation of non-vesicular entities (soluble proteins, RNA-protein complexes and RNA-lipoprotein complexes) from EVs is necessary to determine the true contribution of EVs in any experiment that describes the molecular content or the functional consequences of the isolated material.