Transcriptome sequencing and multi-plex imaging of prostate cancer microenvironment reveals a dominant role for monocytic cells in progression.

BACKGROUND: Prostate cancer is caused by genomic aberrations in normal epithelial cells, however clinical translation of findings from analyses of cancer cells alone has been very limited. A deeper understanding of the tumour microenvironment is needed to identify the key drivers of disease progression and reveal novel therapeutic opportunities. RESULTS: In this study, the experimental enrichment of selected cell-types, the development of a Bayesian inference model for continuous differential transcript abundance, and multiplex immunohistochemistry permitted us to define the transcriptional landscape of the prostate cancer microenvironment along the disease progression axis. An important role of monocytes and macrophages in prostate cancer progression and disease recurrence was uncovered, supported by both transcriptional landscape findings and by differential tissue composition analyses. These findings were corroborated and validated by spatial analyses at the single-cell level using multiplex immunohistochemistry. CONCLUSIONS: This study advances our knowledge concerning the role of monocyte-derived recruitment in primary prostate cancer, and supports their key role in disease progression, patient survival and prostate microenvironment immune modulation.

The modified International Society of Urological Pathology system improves concordance between biopsy and prostatectomy tumour grade.

OBJECTIVES: To assess the concordance between biopsy and radical prostatectomy (RP) specimens using the 2005 Gleason score (GS) and the International Society of Urological Pathology (ISUP) 2014/World Health Organization 2016 modified system, accounting for the introduction of transperineal biopsy and pre-biopsy multiparametric magnetic resonance imaging (mpMRI). PATIENTS AND METHODS: Between 2002 and 2019, we identified 2431 patients with paired biopsy and RP histopathology from a prospectively recorded and maintained prostate cancer database. Biopsy specimens were graded according to the 2005 GS or ISUP 2014 modified system, according to the year of diagnosis. Multivariable logistic regression analysis was conducted to retrospectively assess the impact of prostate-specific antigen (PSA), PSA density, age, pre-biopsy mpMRI, and biopsy method, on the rate of upgraded disease. The kappa coefficient was used to establish the degree of change in concordance between groups. RESULTS: Overall, 24% of patients had upgraded disease and 8% of patients had downgraded disease when using the modified ISUP 2014 criteria. Agreement in the updated ISUP 2014 cohort was 68%, compared with 55% in the 2005 GS group, which was validated by a kappa coefficient that was good (k = 0.5 ± 0.4) and poor (k = 0.3 ± 0.1), respectively. In multivariable models, a change in grading system independently improved overall disease concordance (P = 0.02), and there were no other co-segregated patient or pathological factors such as PSA, total number of cores, maximum cancer length, biopsy route or the use of mpMRI that impacted this finding. CONCLUSION: The 2014 ISUP modifed system improves overall concordance between biopsy and surgical specimens, and thus allows more accurate prognostication and management in high-grade disease, independent of more extensive prostate sampling and the use of mpMRI.

Robotic radical prostatectomy as the initial step in multimodal therapy for men with high-risk localised prostate cancer: initial experience of 160 men.

OBJECTIVES: • To report the outcome of robotic-assisted laparoscopic radical prostatectomy (RALP) for men with localised high-risk prostate cancer at diagnosis. • Although commonly managed by radiotherapy (RT) with prolonged androgen-deprivation therapy (ADT), we hypothesize that initiation of multimodal therapy with RALP is oncologically efficacious and may allow many men to avoid ADT. PATIENTS AND METHODS: • Between December 2003 and September 2010, 1480 men underwent RALP of whom 160 fulfilled the National Comprehensive Control Network criteria for high-risk disease (prostate-specific antigen (PSA) > 20 ng/mL and/or clinical stage, cT ≥ 3 and/or biopsy Gleason score ≥ 8). • Biochemical recurrence (postoperative PSA ≥ 0.2) was used to assess outcome after RALP monotherapy. • Treatment failure was defined as either a rising PSA level after salvage RT or the initiation of ADT. RESULTS: • The mean age ± standard deviation was 63.1 ± 6.3 years. Median PSA level was 9.95 ng/mL (interquartile range 6.0-21.4). • Analysis of prostatectomy specimen showed Gleason 8-10 cancers in 65 (41%), and extracapsular disease, pT ≥ 3, in 96 (60%) of which seminal vesicle invasion was evident in 36 (23%). Downgrading by prostatectomy occurred in 64 (40% of total group) and five (3%) were downstaged to pT2 disease. By contrast, any upgrading occurred in 29 (18% of total group) and upstaging occurred in 68 (43%). The overall positive surgical margin rate was 38%, correlating with stage pT2 (15%) or pT3 (53%). • With median follow-up of 26.2 months (interquartile range 5.5-37.3), two non-cancer-related deaths have occurred (overall survival 98.8%; cancer-specific survival 100%), and biochemical recurrence has occurred in 53 men (33%). RALP surgery has served as monotherapy (n= 117, 73%), or has been followed by salvage RT (n= 24, 15%) and/or ADT (n= 43, 27%). Overall 2-year and 3-year treatment failure was 31 and 41%, respectively. • Serum PSA level was the only independent predictor of overall treatment failure (hazard ratio [HR] 1.02, P= 0.001) although a strong trend was observed for both clinical stage (HR 1.22, P= 0.058) and the number of positive biopsy cores on transrectal biopsy (HR 1.06, P= 0.057). CONCLUSIONS: • RALP incorporating the use of postoperative RT is a good multimodal management strategy for men with this aggressive variant of prostate cancer. • At median follow-up in excess of 2 years, we found low rates of treatment failure enabling a high proportion of men to remain free of ADT.

Phase 2 Study of Neoadjuvant FGFR Inhibition and Androgen Deprivation Therapy Prior to Prostatectomy.

BACKGROUND: Disease recurrence is common following prostatectomy in patients with localised prostate cancer with high-risk features. Although androgen deprivation therapy increases the rates of organ-confined disease and negative surgical margins, there is no significant benefit on disease recurrence. Multiple lines of evidence suggest that (Fibroblast Growth Factor/Fibroblast Growth Factor Receptor) FGF/FGFR-signalling is important in supporting prostate epithelial cell survival in hostile conditions, including acute androgen deprivation. Given the recent availability of oral FGFR inhibitors, we investigated whether combination therapy could improve tumour response in the neo-adjuvant setting. METHODS: We conducted an open label phase II study of the combination of erdafitinib (3 months) and androgen deprivation therapy (4 months) in men with localised prostate cancer with high-risk features prior to prostatectomy using a Simon's 2 stage design. The co-primary endpoints were safety and tolerability and pathological response in the prostatectomy specimen. The effect of treatment on residual tumours was explored by global transcriptional profiling with RNA-sequencing. RESULTS: Nine patients were enrolled in the first stage of the trial. The treatment combination was poorly tolerated. Erdafitinib treatment was discontinued early in six patients, three of whom also required dose interruptions/reductions. Androgen deprivation therapy for 4 months was completed in all patients. The most common adverse events were hyperphosphataemia, taste disturbance, dry mouth and nail changes. No patients achieved a complete pathological response, although patients who tolerated erdafitinib for longer had smaller residual tumours, associated with reduced transcriptional signatures of epithelial cell proliferation. CONCLUSIONS: Although there was a possible enhanced anti-tumour effect of androgen deprivation therapy in combination with erdafitnib in treatment naïve prostate cancer, the poor tolerability in this patient population prohibits the use of this combination in this setting.

MSH2-deficient prostate tumours have a distinct immune response and clinical outcome compared to MSH2-deficient colorectal or endometrial cancer.

BACKGROUND: Recent publications have shown patients with defects in the DNA mismatch repair (MMR) pathway driven by either MSH2 or MSH6 loss experience a significant increase in the incidence of prostate cancer. Moreover, this increased incidence of prostate cancer is accompanied by rapid disease progression and poor clinical outcomes. METHODS AND RESULTS: We show that androgen-receptor activation, a key driver of prostate carcinogenesis, can disrupt the MSH2 gene in prostate cancer. We screened tumours from two cohorts (recurrent/non-recurrent) of prostate cancer patients to confirm the loss of MSH2 protein expression and identified decreased MSH2 expression in recurrent cases. Stratifying the independent TCGA prostate cancer cohort for MSH2/6 expression revealed that patients with lower levels of MSH2/6 had significant worse outcomes, in contrast, endometrial and colorectal cancer patients with lower MSH2/6 levels. MMRd endometrial and colorectal tumours showed the expected increase in mutational burden, microsatellite instability and enhanced immune cell mobilisation but this was not evident in prostate tumours. CONCLUSIONS: We have shown that loss or reduced levels of MSH2/MSH6 protein in prostate cancer is associated with poor outcome. However, our data indicate that this is not associated with a statistically significant increase in mutational burden, microsatellite instability or immune cell mobilisation in a cohort of primary prostate cancers.

Loss of SNAI2 in Prostate Cancer Correlates With Clinical Response to Androgen Deprivation Therapy.

PURPOSE: Androgen receptor (AR) signaling is important in prostate cancer progression, and therapies that target this pathway have been the mainstay of treatment for advanced disease for over 70 years. Tumors eventually progress despite castration through a number of well-characterized mechanisms; however, little is known about what determines the magnitude of response to short-term pathway inhibition. METHODS: We evaluated a novel combination of AR-targeting therapies (degarelix, abiraterone, and bicalutamide) and noted that the objective patient response to therapy was highly variable. To investigate what was driving treatment resistance in poorly responding patients, as a secondary outcome we comprehensively characterized pre- and post-treatment samples using both whole-genome and RNA sequencing. RESULTS: We find that resistance following short-term treatment differs molecularly from typical progressive castration-resistant disease, associated with transcriptional reprogramming, to a transitional epithelial-to-mesenchymal transition (EMT) phenotype rather than an upregulation of AR signaling. Unexpectedly, tolerance to therapy appears to be the default state, with treatment response correlating with the prevalence of tumor cells deficient for SNAI2, a key regulator of EMT reprogramming. CONCLUSION: We show that EMT characterizes acutely resistant prostate tumors and that deletion of SNAI2, a key transcriptional regulator of EMT, correlates with clinical response.

Detection of ctDNA in plasma of patients with clinically localised prostate cancer is associated with rapid disease progression.

BACKGROUND: DNA originating from degenerate tumour cells can be detected in the circulation in many tumour types, where it can be used as a marker of disease burden as well as to monitor treatment response. Although circulating tumour DNA (ctDNA) measurement has prognostic/predictive value in metastatic prostate cancer, its utility in localised disease is unknown. METHODS: We performed whole-genome sequencing of tumour-normal pairs in eight patients with clinically localised disease undergoing prostatectomy, identifying high confidence genomic aberrations. A bespoke DNA capture and amplification panel against the highest prevalence, highest confidence aberrations for each individual was designed and used to interrogate ctDNA isolated from plasma prospectively obtained pre- and post- (24 h and 6 weeks) surgery. In a separate cohort (n = 189), we identified the presence of ctDNA TP53 mutations in preoperative plasma in a retrospective cohort and determined its association with biochemical- and metastasis-free survival. RESULTS: Tumour variants in ctDNA were positively identified pre-treatment in two of eight patients, which in both cases remained detectable postoperatively. Patients with tumour variants in ctDNA had extremely rapid disease recurrence and progression compared to those where variants could not be detected. In terms of aberrations targeted, single nucleotide and structural variants outperformed indels and copy number aberrations. Detection of ctDNA TP53 mutations was associated with a significantly shorter metastasis-free survival (6.2 vs. 9.5 years (HR 2.4; 95% CIs 1.2-4.8, p = 0.014). CONCLUSIONS: CtDNA is uncommonly detected in localised prostate cancer, but its presence portends more rapidly progressive disease.

Androgen deprivation therapy promotes an obesity-like microenvironment in periprostatic fat.

Prostate cancer is a leading cause of morbidity and cancer-related death worldwide. Androgen deprivation therapy (ADT) is the cornerstone of management for advanced disease. The use of these therapies is associated with multiple side effects, including metabolic syndrome and truncal obesity. At the same time, obesity has been associated with both prostate cancer development and disease progression, linked to its effects on chronic inflammation at a tissue level. The connection between ADT, obesity, inflammation and prostate cancer progression is well established in clinical settings; however, an understanding of the changes in adipose tissue at the molecular level induced by castration therapies is missing. Here, we investigated the transcriptional changes in periprostatic fat tissue induced by profound ADT in a group of patients with high-risk tumours compared to a matching untreated cohort. We find that the deprivation of androgen is associated with a pro-inflammatory and obesity-like adipose tissue microenvironment. This study suggests that the beneficial effect of therapies based on androgen deprivation may be partially counteracted by metabolic and inflammatory side effects in the adipose tissue surrounding the prostate.

3D modelling of radical prostatectomy specimens: Developing a method to quantify tumor morphometry for prostate cancer risk prediction.

Prostate cancer displays a wide spectrum of clinical behaviour from biological indolence to rapidly lethal disease, but we remain unable to accurately predict an individual tumor's future clinical course at an early curable stage. Beyond basic dimensions and volume calculations, tumor morphometry is an area that has received little attention, as it requires the analysis of the prostate gland and tumor foci in three-dimensions. Previous efforts to generate three-dimensional prostate models have required specialised graphics units and focused on the spatial distribution of tumors for optimisation of biopsy strategies rather than to generate novel morphometric variables such as tumor surface area. Here, we aimed to develop a method of creating three-dimensional models of a prostate's pathological state post radical prostatectomy that allowed the derivation of surface areas and volumes of both prostate and tumors, to assess the method's accuracy to known clinical data, and to perform initial investigation into the utility of morphometric variables in prostate cancer prognostication. Serial histology slides from 21 prostatectomy specimens covering a range of tumor sizes and pathologies were digitised. Computer generated three-dimensional models of tumor and prostate space filling models were reconstructed from these scanned images using Rhinoceros 4.0 spatial reconstruction software. Analysis of three-dimensional modelled prostate volume correlated only moderately with weak concordance to that from the clinical data (r=0.552, θ=0.405), but tumor volume correlated well with strong concordance (r=0.949, θ=0.876). We divided the cohort of 21 patients into those with features of aggressive tumor versus those without and found that larger tumor surface area (32.7 vs 3.4cc, p=0.008) and a lower tumor surface area to volume ratio (4.7 vs 15.4, p=0.008) were associated with aggressive tumor biology.

Tracking the origins and drivers of subclonal metastatic expansion in prostate cancer.

Tumour heterogeneity in primary prostate cancer is a well-established phenomenon. However, how the subclonal diversity of tumours changes during metastasis and progression to lethality is poorly understood. Here we reveal the precise direction of metastatic spread across four lethal prostate cancer patients using whole-genome and ultra-deep targeted sequencing of longitudinally collected primary and metastatic tumours. We find one case of metastatic spread to the surgical bed causing local recurrence, and another case of cross-metastatic site seeding combining with dynamic remoulding of subclonal mixtures in response to therapy. By ultra-deep sequencing end-stage blood, we detect both metastatic and primary tumour clones, even years after removal of the prostate. Analysis of mutations associated with metastasis reveals an enrichment of TP53 mutations, and additional sequencing of metastases from 19 patients demonstrates that acquisition of TP53 mutations is linked with the expansion of subclones with metastatic potential which we can detect in the blood.

Peer-delivered hepatitis C testing and counselling: a means of improving the health of injecting drug users.

We hypothesized that providing injecting drug users (IDUs) with free hepatitis C testing and counselling at a needle and syringe programme (NSP) would be an effective model. Between August 1999 and January 2000, our peer outreach worker offered these services from a busy NSP in western Melbourne. Over 300 counselling episodes were provided, and 47 IDUs who were not tested in the previous 12 months were given tests and full pre- and post-test counselling, and were interviewed about reasons for not being tested, their knowledge of hepatitis C, and their risk behaviour. Twenty-eight IDUs (59.6%) tested antibody-positive, demonstrating the need to improve testing coverage and compliance with counselling requirements. Most were not tested because they did not think they were at risk, but their reported behaviour and antibody test results showed otherwise. Twenty people returned for a second interview, and improvements in their risk behaviour and knowledge of hepatitis C were detected. Our experience suggests that demand exists for hepatitis C testing and counselling of IDUs in Melbourne's western suburbs, that testing and counselling improve IDUs' ability to avoid harm, and that delivery of these services by a trained and experienced peer located at an NSP is an appropriate and effective model.

Percutaneous image-guided biopsy of prostate cancer metastases yields samples suitable for genomics and personalised oncology.

Personalised oncology through mutational profiling of cancers requires the procurement of fresh frozen tumour samples for genomics applications. While primary cancers are often surgically excised and therefore yield such tissue, metastases in the setting of a known cancer diagnosis are not routinely sampled prior to systemic therapy. Our study aimed to determine the suitability of extracted nucleic acids for genomics applications using distant metastatic prostate cancer samples obtained via percutaneous or surgical biopsy. Patients with metastatic prostate cancer were recruited for image-guided biopsy of metastases. Patients undergoing surgical procedures for the complications of metastases were also recruited. Tissue samples were flash frozen and cryosectioned for histological examination. DNA and RNA were simultaneously extracted and genomic DNA hybridised onto SNP arrays for genome-wide copy number analysis. 37 samples of metastatic tissue from seven patients with prostate cancer were obtained. Five of these underwent image-guided biopsies whilst two had therapeutic surgical procedures performed. 22 biopsy samples were obtained across the image-guided biopsy patients with 80 % of samples being successfully processed for downstream analysis. Nucleic acid yield from these samples were satisfactory for genomics applications. Copy number analysis revealed a median estimated tumour purity of 53 % and all samples showed chromosomal abnormalities suggestive of malignancy. The procurement of osseous metastatic prostate cancer from live patients, including the use of image-guided biopsy, is safe and feasible. Sufficient tissue can be obtained in a manner such that extracted nucleic acids are suitable for genomics research.

Microscopic assessment of fresh prostate tumour specimens yields significantly increased rates of correctly annotated samples for downstream analysis.

AIMS: To assess if performing frozen sections of tissue biopsies from fresh radical prostatectomy specimens, prior to tissue banking, could improve the identification of the banked samples compared to standard fresh tumour banking procedures. METHODS: Tissue biopsies banked from 332 fresh prostatectomy specimens were assessed for accuracy of diagnosis, comparing two separate methods of tumour identification: one in which tumour was identified in the gross specimen by visual inspection (n = 155) and one in which rapid frozen sectioning was applied (n = 177). The associations with correct tumour annotation and clinicopathological variables, including age, pre-operative prostate specific antigen (PSA) levels, pathological Gleason score, pathological T stage, tumour volume and surgical margins, were examined using univariable and multivariable binary logistic regression models. RESULTS: For the gross visual inspection cohort the rate of correctly identifying and banking specimens containing prostate cancer was 69%. For the cohort assessed with rapid frozen sections, 94% of banked specimens actually had cancer. On multivariable analysis, we found that only frozen sectioning and tumour volume variables were independent predictors of correctly banked tumour specimens whilst all other routinely reported pathological variables had no influence on the success rates of fresh prostate tumour banking. CONCLUSION: The success rate for correctly banking fresh prostate tumour specimens is directly related to the tumour volume. Frozen section scrutiny of prostate samples is recommended to prevent misclassification of the banked material.

Operative details and oncological and functional outcome of robotic-assisted laparoscopic radical prostatectomy: 400 cases with a minimum of 12 months follow-up.

BACKGROUND: Robotic-assisted laparoscopic radical prostatectomy (RALP) using the da Vinci surgical system (Intuitive Surgical, Sunnyvale, CA) is increasingly used for the management of localised prostate cancer. OBJECTIVE: We report the operative details and short-term oncological and functional outcome of the first 400 RALPs performed at our unit. DESIGN, SETTING AND PARTICIPANTS: From December 2003 to August 2006, 400 consecutive patients underwent RALP at our institution. A prospective database was established to record the relevant details of all RALP cases. SURGICAL PROCEDURE: A six port transperitoneal approach using a 4-arm da Vinci system was used to perform RALP. This database was reviewed to establish the operative details and oncological and functional outcome of all patients with a minimum of 12 months follow-up. MEASUREMENTS: Perioperative characteristics and outcomes are reported. Functional outcome was assessed using continence and erectile function questionnaires. Biochemical recurrence (prostate-specific antigen (PSA) > or =0.2 ng/mL) is used as a surrogate for cancer control. RESULTS AND LIMITATIONS: The mean age+/-standard deviation (SD) was 60.2+/-6 years. Median PSA level was 7.0 (interquartile range (IQR) 5.3-9.6) ng/mL. The mean operating time+/-SD was 186+/-49 mins. The complication rate was 15.75% comprising Clavien grade I-II and Clavien grade III complications in 10.5% and 5.25% of patients respectively. The overall positive surgical margin rate was 19.2% with T2 and T3 positive margin rates of 9.6% and 42.3% respectively. The biochemical recurrence-free survival was 86.6% at a median follow-up of 22 (IQR=15-30) months. At 12 months follow-up, 91.4% of patients were pad-free or used a security liner. Of those men previously potent (defined as Sexual Health Inventory for Men [SHIM] score > or =21) who underwent nerve-sparing RALP, 62% were potent at 12 months. CONCLUSIONS: The safety and feasibility of RALP has already been established. Our initial experience with this procedure shows promising short-term outcomes.

Molecular epidemiology of hepatitis C virus in a social network of injection drug users.

BACKGROUND: We aimed to measure the overlap between the social networks of injection drug users (IDUs) and the patterns of related hepatitis C virus (HCV) infections among IDUs. METHODS: A cohort of 199 IDUs (138 of whom were HCV RNA positive) was recruited from a local drug scene in Melbourne, Australia, and was studied using social network analysis and molecular phylogenetic analysis of 2 regions of the HCV genome. RESULTS: Eighteen clusters of related infections involving 51 IDUs (37.0% of HCV RNA-positive IDUs) were detected; these clusters could be separated into 66 discrete pairs. Twelve (18.2%) of the 66 IDU pairs with related infections reported having previously injected drugs together; conversely, only 12 (3.8%) of the 313 pairs of HCV RNA-positive IDUs who were injection partners had strong molecular evidence of related infections. The social and genetic distances that separated IDUs with identical genotypes were weakly associated. Significant clusters of phylogenetically related sequences identified from core region analysis persisted in the analysis of the nonstructural 5a protein region. Genotyping and sequence analysis revealed 2 mixed-genotype infections. CONCLUSIONS: Static social network methods are likely to gather information about a minority of patterns of HCV transmission, because of the difficulty of determining historical infection pathways in an established social network of IDUs. Nevertheless, molecular epidemiological methods identified clusters of IDUs with related viruses and provided information about mixed-genotype infection status.