EGFR targeting PhosTACs as a dual inhibitory approach reveals differential downstream signaling.

We recently developed a heterobifunctional approach [phosphorylation targeting chimeras (PhosTACs)] to achieve the targeted protein dephosphorylation (TPDephos). Here, we envisioned combining the inhibitory effects of receptor tyrosine kinase inhibitors (RTKIs) and the active dephosphorylation by phosphatases to achieve dual inhibition of kinases. We report an example of tyrosine phosphatase-based TPDephos and the effective epidermal growth factor receptor (EGFR) tyrosine dephosphorylation. We also used phosphoproteomic approaches to study the signaling transductions affected by PhosTAC-related molecules at the proteome-wide level. This work demonstrated the differential signaling pathways inhibited by PhosTAC compared with the TKI, gefitinib. Moreover, a covalent PhosTAC selective for mutated EGFR was developed and showed its inhibitory potential for dysregulated EGFR. Last, EGFR PhosTACs, consistent with EGFR dephosphorylation profiles, induced apoptosis and inhibited cancer cell viability during prolonged PhosTAC treatment. PhosTACs showcased their potential of modulating RTKs activity, expanding the scope of bifunctional molecule utility.

Development of a Small Molecule Downmodulator for the Transcription Factor Brachyury.

Brachyury is an oncogenic transcription factor whose overexpression drives chordoma growth. The downmodulation of brachyury in chordoma cells has demonstrated therapeutic potential, however, as a transcription factor it is classically deemed "undruggable". Given that direct pharmacological intervention against brachyury has proven difficult, attempts at intervention have instead targeted upstream kinases. Recently, afatinib, an FDA-approved kinase inhibitor, has been shown to modulate brachyury levels in multiple chordoma cell lines. Herein, we use afatinib as a lead to undertake a structure-based drug design approach, aided by mass-spectrometry and X-ray crystallography, to develop DHC-156, a small molecule that more selectively binds brachyury and downmodulates it as potently as afatinib. We eliminated kinase-inhibition from this novel scaffold while demonstrating that DHC-156 induces the post-translational downmodulation of brachyury that results in an irreversible impairment of chordoma tumor cell growth. In doing so, we demonstrate the feasibility of direct brachyury modulation, which may further be developed into more potent tool compounds and therapies.

Picture Perfect: The Status of Image Quality in Prostate MRI.

Magnetic resonance imaging is the gold standard imaging modality for the diagnosis of prostate cancer (PCa). Image quality is a fundamental prerequisite for the ability to detect clinically significant disease. In this critical review, we separate the issue of image quality into quality improvement and quality assessment. Beginning with the evolution of technical recommendations for scan acquisition, we investigate the role of patient preparation, scanner factors, and more advanced sequences, including those featuring Artificial Intelligence (AI), in determining image quality. As means of quality appraisal, the published literature on scoring systems (including the Prostate Imaging Quality score), is evaluated. Finally, the application of AI and teaching courses as ways to facilitate quality assessment are discussed, encouraging the implementation of future image quality initiatives along the PCa diagnostic and monitoring pathway. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 3.

Establishing the predictive validity of the intercollegiate membership of the Royal Colleges of surgeons written examination: MRCS part B.

The Intercollegiate Membership of the Royal Colleges of Surgeons (MRCS) is a high-stakes postgraduate examination taken by thousands of surgical trainees worldwide every year. The MRCS is a challenging assessment, highly regarded by surgical training programmes and valued as a gatekeeper to the surgical profession. The examination is taken at considerable personal, social and financial cost to surgical trainees, and failure has significant implications for career progression. Given the value placed on MRCS, it must be a reliable and valid assessment of the knowledge and skills of early-career surgeons. Our first article 'Establishing the Predictive Validity of the Intercollegiate Membership of the Royal Colleges of Surgeons Written Examination: MRCS Part A' discussed the principles of assessment reliability and validity and outlined the mounting evidence supporting the predictive validity of the MRCS Part A (the multiple-choice questionnaire component of the examination). This, the second article in the series discusses six recently published studies investigating the predictive validity of the MRCS Part B (the clinical component of the examination). All national longitudinal cohort studies reviewed have demonstrated significant correlations between MRCS Part B and other assessments taken during the UK surgical training pathway, supporting the predictive validity of MRCS Part B. This review will be of interest to trainees, trainers and Royal Colleges given the value placed on the examination by surgical training programmes.

A semi-automated software program to assess the impact of second reads in prostate MRI for equivocal lesions: results from a UK tertiary referral centre.

PURPOSE: To investigate the utility of a prostate magnetic resonance imaging (MRI) second read using a semi-automated software program in the one-stop clinic, where patients undergo multiparametric MRI, review and biopsy planning in one visit. We looked at concordance between readers for patients with equivocal scans and the possibility for biopsy deferral in this group. METHODS: We present data from 664 consecutive patients. Scans were reported by seven different expert genitourinary radiologists using dedicated software (MIM®) and a Likert scale. All scans were rescored by another expert genitourinary radiologist using a customised workflow for second reads that includes annotated biopsy contours for accurate visual targeting. The number of scans in which a biopsy could have been deferred using biopsy results and prostate specific antigen density was assessed. Gleason score ≥ 3 + 4 was considered clinically significant disease. Concordance between first and second reads for equivocal scans (Likert 3) was evaluated. RESULTS: A total of 209/664 (31%) patients scored Likert 3 on first read, 128 of which (61%) were concordant after second read. 103/209 (49%) of patients with Likert 3 scans were biopsied, with clinically significant disease in 31 (30%) cases. Considering Likert 3 scans that were both downgraded and biopsied using the workflow-generated biopsy contours, 25/103 (24%) biopsies could have been deferred. CONCLUSIONS: Implementing a semi-automated workflow for accurate lesion contouring and targeting biopsies is helpful during the one-stop clinic. We observed a reduction of indeterminate scans after second reading and almost a quarter of biopsies could have been deferred, reducing the potential biopsy-related side effects.

Examining the diversity of MRCS examiners.

BACKGROUND: MRCS examiners are the face of the Royal College of Surgeons for early-career surgeons and should therefore represent the workforce they are examining as not to marginalise or negatively impact on the assessment experience of candidates from minoritised groups. This study aimed to explore the diversity of MRCS examiners and whether they represent the demographics of the MRCS candidates. METHODS: A retrospective observational study including all active examiners and examination candidates who attempted MRCS Part A or Part B between January 2020 and July 2021. Self-declared demographic data collected by the Intercollegiate Committee for Basic Surgical Examinations (ICBSE) included gender, sexual orientation, disability status and ethnicity. Following data anonymisation, total group response frequencies were made available to the research team for statistical analysis. RESULTS: Chi-squared analyses showed statistically significant differences in the representation of gender, disability and ethnicity between candidates and examiners (all p < 0.001). Men (83.9% (n = 1121) vs 70.9% (n = 6017) respectively), individuals without disability (98.7% (n = 917) vs 96.1% (n = 6847)) and individuals of White ethnicity (36.6% (n = 346) vs 20.4% (n = 1223)) were significantly overrepresented in the examiners compared to the examination candidates. There was no statistically significant difference in sexual orientation between examiners and candidates (p = 0.712). CONCLUSIONS: Broadly speaking, the socio-demographic profile of MRCS examiners reflects that seen in senior and leadership positions in surgery in the UK - that is, predominantly male and White - but not that seen in early-career surgeons. Positive action is now required in examiner recruitment by the Royal Colleges to ensure that the cohort of MRCS examiners reflects the modern surgical workforce.

Regulated Induced Proximity Targeting Chimeras (RIPTACs): a Novel Heterobifunctional Small Molecule Therapeutic Strategy for Killing Cancer Cells Selectively.

While specific cell signaling pathway inhibitors have yielded great success in oncology, directly triggering cancer cell death is one of the great drug discovery challenges facing biomedical research in the era of precision oncology. Attempts to eradicate cancer cells expressing unique target proteins, such as antibody-drug conjugates (ADCs), T-cell engaging therapies, and radiopharmaceuticals have been successful in the clinic, but they are limited by the number of targets given the inability to target intracellular proteins. More recently, heterobifunctional small molecules such as Proteolysis Targeting Chimera (PROTACs) have paved the way for protein proximity inducing therapeutic modalities. Here, we describe a proof-of-concept study using novel heterobifunctional small molecules called Regulated Induced Proximity Targeting Chimeras or RIPTACs, which elicit a stable ternary complex between a target protein selectively expressed in cancer tissue and a pan-expressed protein essential for cell survival. The resulting cooperative protein:protein interaction (PPI) abrogates the function of the essential protein, thus leading to cell death selectively in cells expressing the target protein. This approach not only opens new target space by leveraging differentially expressed intracellular proteins but also has the advantage of not requiring the target to be a driver of disease. Thus, RIPTACs can address non-target mechanisms of resistance given that cell killing is driven by inactivation of the essential protein. Using the HaloTag7-FKBP model system as a target protein, we describe RIPTACs that incorporate a covalent or non-covalent target ligand connected via a linker to effector ligands such as JQ1 (BRD4), BI2536 (PLK1), or multi-CDK inhibitors such as TMX3013 or dinaciclib. We show that these RIPTACs exhibit positive co-operativity, accumulate selectively in cells expressing HaloTag7-FKBP, form stable target:RIPTAC:effector trimers in cells, and induce an anti-proliferative response in target-expressing cells. We propose that RIPTACs are a novel heterobifunctional therapeutic modality to treat cancers that are known to selectively express a specific intracellular protein.

Cost-Utility Analysis of Major System Change in Specialist Cancer Surgery in London, England, Using Linked Patient-Level Electronic Health Records and Difference-in-Differences Analysis.

BACKGROUND: Studies have shown that centralising surgical treatment for some cancers can improve patient outcomes, but there is limited evidence of the impact on costs or health-related quality of life. OBJECTIVES: We report the results of a cost-utility analysis of the RESPECT-21 study using difference-in-differences, which investigated the reconfiguration of specialist surgery services for four cancers in an area of London, compared to the Rest of England (ROE). METHODS: Electronic health records data were obtained from the National Cancer Registration and Analysis Service for patients diagnosed with one of the four cancers of interest between 2012 and 2017. The analysis for each tumour type used a short-term decision tree followed by a 10-year Markov model with 6-monthly cycles. Costs were calculated by applying National Health Service (NHS) Reference Costs to patient-level hospital resource use and supplemented with published data. Cancer-specific preference-based health-related quality-of-life values were obtained from the literature to calculate quality-adjusted life-years (QALYs). Total costs and QALYs were calculated before and after the reconfiguration, in the London Cancer (LC) area and in ROE, and probabilistic sensitivity analysis was performed to illustrate the uncertainty in the results. RESULTS: At a threshold of £30,000/QALY gained, LC reconfiguration of prostate cancer surgery services had a 79% probability of having been cost-effective compared to non-reconfigured services using difference-in-differences. The oesophago-gastric, bladder and renal reconfigurations had probabilities of 62%, 49% and 12%, respectively, of being cost-effective at the same threshold. Costs and QALYs per surgical patient increased over time for all cancers across both regions to varying degrees. Bladder cancer surgery had the smallest patient numbers and changes in costs, and QALYs were not significant. The largest improvement in outcomes was in renal cancer surgery in ROE, making the relative renal improvements in LC appear modest, and the probability of the LC reconfiguration having been cost-effective low. CONCLUSIONS: Prostate cancer reconfigurations had the highest probability of being cost-effective. It is not clear, however, whether the prostate results can be considered in isolation, given the reconfigurations occurred simultaneously with other system changes, and healthcare delivery in the NHS is highly networked and collaborative. Routine collection of quality-of-life measures such as the EQ-5D-5L would have improved the analysis.

Loss associated with subtractive health service change: The case of specialist cancer centralization in England.

OBJECTIVE: Major system change can be stressful for staff involved and can result in 'subtractive change' - that is, when a part of the work environment is removed or ceases to exist. Little is known about the response to loss of activity resulting from such changes. Our aim was to understand perceptions of loss in response to centralization of cancer services in England, where 12 sites offering specialist surgery were reduced to four, and to understand the impact of leadership and management on enabling or hampering coping strategies associated with that loss. METHODS: We analysed 115 interviews with clinical, nursing and managerial staff from oesophago-gastric, prostate/bladder and renal cancer services in London and West Essex. In addition, we used 134 hours of observational data and analysis from over 100 documents to contextualize and to interpret the interview data. We performed a thematic analysis drawing on stress-coping theory and organizational change. RESULTS: Staff perceived that, during centralization, sites were devalued as the sites lost surgical activity, skills and experienced teams. Staff members believed that there were long-term implications for this loss, such as in retaining high-calibre staff, attracting trainees and maintaining autonomy. Emotional repercussions for staff included perceived loss of status and motivation. To mitigate these losses, leaders in the centralization process put in place some instrumental measures, such as joint contracting, surgical skill development opportunities and trainee rotation. However, these measures were undermined by patchy implementation and negative impacts on some individuals (e.g. increased workload or travel time). Relatively little emotional support was perceived to be offered. Leaders sometimes characterized adverse emotional reactions to the centralization as resistance, to be overcome through persuasion and appeals to the success of the new system. CONCLUSIONS: Large-scale reorganizations are likely to provoke a high degree of emotion and perceptions of loss. Resources to foster coping and resilience should be made available to all organizations within the system as they go through major change.

Inter-organisational collaboration enabling care delivery in a specialist cancer surgery provider network: A qualitative study.

OBJECTIVE: To explore the processes, challenges and strategies used to govern and maintain inter-organisational collaboration between professionals in a provider network in London, United Kingdom, which implemented major system change focused on the centralisation of specialist cancer surgery. METHODS: We used a qualitative design involving interviews with stakeholders (n = 117), non-participant observations (n = 163) and documentary analysis (n = 100). We drew on an existing model of collaboration in healthcare organisations and expanded this framework by applying it to the analysis of collaboration in the context of major system change. RESULTS: Network provider organisations established shared goals, maintained central figures who could create and sustain collaboration, and promoted distributed forms of leadership. Still, organisations continued to encounter barriers or challenges in relation to developing opportunities for mutual acquaintanceship across all professional groups; the active sharing of knowledge, expertise and good practice across the network; the fostering of trust; and creation of information exchange infrastructures fit for collaborative purposes. CONCLUSION: Collaborative relationships changed over time, becoming stronger post-implementation in some areas, but continued to be negotiated where resistance to the centralisation remained. Future research should explore the sustainability of these relationships and further unpack how hierarchies and power relationships shape inter-organisational collaboration.

The Incidental Renal Mass- Update on Characterization and Management.

Renal masses are commonly encountered on cross-sectional imaging examinations performed for nonrenal indications. Although most can be dismissed as benign cysts, a subset will be either indeterminate or suspicious; in many cases, imaging cannot be used to reliably differentiate between benign and malignant masses. On-going research in defining characteristics of common renal masses on advanced imaging shows promise in offering solutions to this issue. A recent update of the Bosniak classification (used to categorize cystic renal masses) was proposed with the goals of decreasing imaging follow-up in likely benign cystic masses, and therefore avoiding unnecessary surgical resection of such masses.

Spectrum and Relevance of Incidental Bowel Findings on Computed Tomography.

A wide spectrum of incidental bowel findings can be seen on CT, including but not limited to, pneumatosis intestinalis, diverticular disease, non-obstructive bowel dilatation, transient small bowel intussusception, and submucosal fat. Radiologists should be aware that such findings are almost always benign and of little clinical significance in the absence of associated symptoms. Conversely, vigilance must be maintained when evaluating the bowel, because malignant neoplasms occasionally come to clinical attention as incidental imaging findings. When suspicious incidental bowel wall thickening is detected, the radiologist can alert the clinical team to the finding prior to the patient becoming symptomatic, potentially leading to definitive management at an early, more curable stage.

How to Cost the Implementation of Major System Change for Economic Evaluations: Case Study Using Reconfigurations of Specialist Cancer Surgery in Part of London, England.

BACKGROUND: Studies have been published regarding the impact of major system change (MSC) on care quality and outcomes, but few evaluate implementation costs or include them in cost-effectiveness analysis (CEA). This is despite large potential costs of MSC: change planning, purchasing or repurposing assets, and staff time. Implementation costs can influence implementation decisions. We describe our framework and principles for costing MSC implementation and illustrate them using a case study. METHODS: We outlined MSC implementation stages and identified components, using a framework conceived during our work on MSC in stroke services. We present a case study of MSC of specialist surgery services for prostate, bladder, renal and oesophagogastric cancers, focusing on North Central and North East London and West Essex. Health economists collaborated with qualitative researchers, clinicians and managers, identifying key reconfiguration stages and expenditures. Data sources (n = approximately 100) included meeting minutes, interviews, and business cases. National Health Service (NHS) finance and service managers and clinicians were consulted. Using bottom-up costing, items were identified, and unit costs based on salaries, asset costs and consultancy fees assigned. Itemised costs were adjusted and summed. RESULTS: Cost components included options appraisal, bidding process, external review; stakeholder engagement events; planning/monitoring boards/meetings; and making the change: new assets, facilities, posts. Other considerations included hospital tariff changes; costs to patients; patient population; and lifetime of changes. Using the framework facilitated data identification and collection. The total adjusted implementation cost was estimated at £7.2 million, broken down as replacing robots (£4.0 million), consultancy fees (£1.9 million), staff time costs (£1.1 million) and other costs (£0.2 million). CONCLUSIONS: These principles can be used by funders, service providers and commissioners planning MSC and researchers evaluating MSC. Health economists should be involved early, alongside qualitative and health-service colleagues, as retrospective capture risks information loss. These analyses are challenging; many cost factors are difficult to identify, access and measure, and assumptions regarding lifetime of the changes are important. Including implementation costs in CEA might make MSC appear less cost effective, influencing future decisions. Future work will incorporate this implementation cost into the full CEAs of the London Cancer MSC. TRIAL REGISTRATION: Not applicable.

A Phase II, Open-label study to assess safety and management change using 68Ga-THP PSMA PET/CT in patients with high risk primary prostate cancer or biochemical recurrence after radical treatment: The PRONOUNCED study.

Objectives: To assess the safety and clinical impact of a novel, kit-based formulation of 68Ga-THP PSMA positron emission tomography/computed tomography (PET/CT) when used to guide the management of patients with prostate cancer (PCa). Methods: Patients were prospectively recruited in to one of: Group A: high-risk untreated prostate cancer; Gleason score >4+3, or PSA >20 ng/mL or clinical stage >T2c. Group B: biochemical recurrence (BCR) and eligible for salvage treatment after radical prostatectomy with two consecutive rises in prostate specific antigen (PSA) with a three month interval in between reads and final PSA >0.1 ng/mL or a PSA level >0.5 ng/mL. Group C: BCR with radical curative radiotherapy or brachytherapy at least three months prior to enrolment, and an increase in PSA level >2.0 ng/mL above the nadir level after radiotherapy or brachytherapy. Patients underwent evaluation with PET/CT 60 minutes following intravenous administration of 160±30 MBq of 68Ga-THP PSMA. Safety was assessed by means including vital signs, cardiovascular profile, serum haematology, biochemistry, urinalysis, PSA, and Adverse Events (AEs). A change in management was reported when the predefined clinical management of the patient altered as a result of 68Ga-THP PSMA PET/CT findings. Results: Forty-nine patients were evaluated with PET/CT; 20 in Group A, 21 in Group B and 8 in Group C. No patients experienced serious AEs discontinued the study due to AEs, or died during the study. Two patients had Treatment Emergent AEs attributed to 68Ga-THP-PSMA (pruritus in one patient and intravenous catheter site rash in another). Management change secondary to PET/CT occurred in 42.9% of all patients; 30% in Group A, 42.9% in Group B and 75% in Group C. Conclusion: 68Ga-THP PSMA was safe to use with no serious AE and no AE resulting in withdrawal from the study. 68Ga-THP PSMA PET/CT changed the management of patients in 42.9% of the study population, comparable to studies using other PSMA tracers. These data form the basis of a planned Phase III study of 68Ga-THP PSMA in patients with prostate cancer.

Mutant-selective degradation by BRAF-targeting PROTACs.

Over 300 BRAF missense mutations have been identified in patients, yet currently approved drugs target V600 mutants alone. Moreover, acquired resistance inevitably emerges, primarily due to RAF lesions that prevent inhibition of BRAF V600 with current treatments. Therefore, there is a need for new therapies that target other mechanisms of activated BRAF. In this study, we use the Proteolysis Targeting Chimera (PROTAC) technology, which promotes ubiquitination and degradation of neo-substrates, to address the limitations of BRAF inhibitor-based therapies. Using vemurafenib-based PROTACs, we achieve low  nanomolar degradation of all classes of BRAF mutants, but spare degradation of WT RAF family members. Our lead PROTAC outperforms vemurafenib in inhibiting cancer cell growth and shows in vivo efficacy in a Class 2 BRAF xenograft model. Mechanistic studies reveal that BRAFWT is spared due to weak ternary complex formation in cells owing to its quiescent inactivated conformation, and activation of BRAFWT sensitizes it to degradation. This study highlights the degree of selectivity achievable with degradation-based approaches by targeting mutant BRAF-driven cancers while sparing BRAFWT, providing an anti-tumor drug modality that expands the therapeutic window.

Lingual Tonsillectomy: Successful Treatment of Periodic Fever, Aphthous Stomatitis, Pharyngitis, and Cervical Adenitis Syndrome.

BACKGROUND: PFAPA (periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis) syndrome is diagnosed clinically. Adult-onset PFAPA syndrome is rare and often has a more diverse clinical presentation that its childhood counterpart. This is the first reported case of adult-onset PFAPA syndrome with complete response to lingual tonsillectomy. CASE SUMMARY: A 41-year-old man was evaluated for periodic fevers associated with uvulitis, cervical lymphadenitis, pharyngitis, and lower extremity rash. He had a variable response to steroids and was intolerant of colchicine. Laboratory workup revealed intermittent elevation of erythrocyte sedimentation rate and C-reactive protein level. Computed tomography neck and laryngoscopy confirmed adenoidal and lingual tonsillar hypertrophy. He underwent adenoidectomy and lingual tonsillectomy with resolution of symptoms. CONCLUSIONS: Hypertrophy of the remaining lymphoid structures within Waldeyer's ring may be associated with remote recurrence of PFAPA syndrome after tonsillectomy. Lingual tonsillectomy may be an alternative treatment strategy in select patients with PFAPA, prominent lingual hypertrophy, and incomplete response to steroids.

Implementing major system change in specialist cancer surgery: The role of provider networks.

OBJECTIVE: Major system change (MSC) has multiple, sometimes conflicting, goals and involves implementing change across a number of organizations. This study sought to develop new understanding of how the role that networks can play in implementing MSC, using the case of centralization of specialist cancer surgery in London, UK. METHODS: The study was based on a framework drawn from literature on networks and MSC. We analysed 100 documents, conducted 134 h of observations during relevant meetings and 81 interviews with stakeholders involved in the centralization. We analysed the data using thematic analysis. RESULTS: MSC in specialist cancer services was a contested process, which required constancy in network leadership over several years, and its horizontal and vertical distribution across the network. A core central team composed of network leaders, managers and clinical/manager hybrid roles was tasked with implementing the changes. This team developed different forms of engagement with provider organizations and other stakeholders. Some actors across the network, including clinicians and patients, questioned the rationale for the changes, the clinical evidence used to support the case for change, and the ways in which the changes were implemented. CONCLUSIONS: Our study provides new understanding of MSC by discussing the strategies used by a provider network to facilitate complex changes in a health care context in the absence of a system-wide authority.

A cohort study of 30 day mortality after NON-EMERGENCY surgery in a COVID-19 cold site.

BACKGROUND: Two million non-emergency surgeries are being cancelled globally every week due to the COVID-19 pandemic, which will have a major impact on patients and healthcare systems. METHODS: During the peak of the pandemic in the United Kingdom, we set up a multicentre cancer network amongst 14 National Health Service institutions, performing urological, thoracic, gynaecological and general surgical urgent and cancer operations at a central COVID-19 cold site. This is a cohort study of 500 consecutive patients undergoing surgery in this network. The primary outcome was 30-day mortality from COVID-19. Secondary outcomes included all-cause mortality and post-operative complications at 30-days. RESULTS: 500 patients underwent surgery with median age 62.5 (IQR 51-71). 65% were male, 60% had a known diagnosis of cancer and 61% of surgeries were considered complex or major. No patient died from COVID-19 at 30-days. 30-day all-cause mortality was 3/500 (1%). 10 (2%) patients were diagnosed with COVID-19, 4 (1%) with confirmed laboratory diagnosis and 6 (1%) with probable COVID-19. 33/500 (7%) of patients developed Clavien-Dindo grade 3 or higher complications, with 1/33 (3%) occurring in a patient with COVID-19. CONCLUSION: It is safe to continue cancer and urgent surgery during the COVID-19 pandemic with appropriate service reconfiguration.

The Identification of Plasma Exosomal miR-423-3p as a Potential Predictive Biomarker for Prostate Cancer Castration-Resistance Development by Plasma Exosomal miRNA Sequencing.

Castration-resistant prostate cancer (CRPC) is the major cause of death from prostate cancer. Biomarkers to improve early detection and prediction of CRPC especially using non-invasive liquid biopsies could improve outcomes. Therefore, we investigated the plasma exosomal miRNAs associated with CRPC and their potential for development into non-invasive early detection biomarkers for resistance to treatment. RNA-sequencing, which generated approximately five million reads per patient, was performed to identify differentially expressed plasma exosomal miRNAs in 24 treatment-naive prostate cancer and 24 CRPC patients. RT-qPCR was used to confirm the differential expressions of six exosomal miRNAs, miR-423-3p, miR-320a, miR-99a-5p, miR-320d, miR-320b, and miR-150-5p (p = 7.3 × 10-8, 0.0020, 0.018, 0.0028, 0.0013, and 0.0058, respectively) firstly in a validation cohort of 108 treatment-naive prostate cancer and 42 CRPC patients. The most significant differentially expressed miRNA, miR-423-3p, was shown to be associated with CRPC with area under the ROC curve (AUC) = 0.784. Combining miR-423-3p with prostate-specific antigen (PSA) enhanced the prediction of CRPC (AUC = 0.908). A separate research center validation with 30 treatment-naive and 30 CRPC patients also confirmed the differential expression of miR-423-3p (p = 0.016). Finally, plasma exosomal miR-423-3p expression in CRPC patients was compared to 36 non-CRPC patients under androgen depletion therapy, which showed significantly higher expression in CRPC than treated non-CRPC patients (p < 0.0001) with AUC = 0.879 to predict CRPC with no difference between treatment-naive and treated non-CRPC patients. Therefore, our findings demonstrate that a number of plasma exosomal miRNAs are associated with CRPC and miR-423-3p may serve as a biomarker for early detection/prediction of castration-resistance.