Performance of clinical risk scores and prediction models to identify pathogenic germline variants in patients with advanced prostate cancer.

PURPOSE: Determining the frequency and distribution of pathogenic germline variants (PGVs) in Austrian prostate cancer (PCa) patients and to assess the accuracy of different clinical risk scores to correctly predict PGVs. METHODS: This cross-sectional study included 313 men with advanced PCa. A comprehensive personal and family history was obtained based on predefined questionnaires. Germline DNA sequencing was performed between 2019 and 2021 irrespective of family history, metastatic or castration status or age at diagnosis. Clinical risk scores for hereditary cancer syndromes were evaluated and a PCa-specific score was developed to assess the presence of PGVs. RESULTS: PGV presence was associated with metastasis (p = 0.047) and castration resistance (p = 0.011), but not with personal cancer history or with relatives with any type of cancer. Clinical risk scores (Manchester score, PREMM5 score, Amsterdam II criteria or Johns Hopkins criteria) showed low sensitivities (3.3-20%) for assessing the probability of PGV presence. A score specifically designed for PCa patients stratifying patients into low- or high-risk regarding PGV probability, correctly classified all PGV carriers as high-risk, whereas a third of PCa patients without PGVs was classified as low risk of the presence of PGVs. CONCLUSION: Application of common clinical risk scores based on family history are not suitable to identify PCa patients with high PGV probabilities. A PCa-specific score stratified PCa patients into low- or high-risk of PGV presence with sufficient accuracy, and germline DNA sequencing may be omitted in patients with a low score. Further studies are needed to evaluate the score.

Blood-Based Biomarkers as Prognostic Factors of Recurrent Disease after Radical Cystectomy: A Systematic Review and Meta-Analysis.

Survival outcomes after radical cystectomy (RC) for bladder cancer (BCa) have not improved in recent decades; nevertheless, RC remains the standard treatment for patients with localized muscle-invasive BCa. Identification of the patients most likely to benefit from RC only versus a combination with systemic therapy versus systemic therapy first/only and bladder-sparing is needed. This systematic review and meta-analysis pools the data from published studies on blood-based biomarkers to help prognosticate disease recurrence after RC. A literature search on PubMed and Scopus was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. Articles published before November 2022 were screened for eligibility. A meta-analysis was performed on studies investigating the association of the neutrophil-to-lymphocyte ratio (NLR), the only biomarker with sufficient data, with recurrence-free survival. The systematic review identified 33 studies, and 7 articles were included in the meta-analysis. Our results demonstrated a statistically significant correlation between elevated NLR and an increased risk of disease recurrence (HR 1.26; 95% CI 1.09, 1.45; p = 0.002) after RC. The systematic review identified various other inflammatory biomarkers, such as interleukin-6 or the albumin-to-globulin ratio, which have been reported to have a prognostic impact on recurrence after RC. Besides that, the nutritional status, factors of angiogenesis and circulating tumor cells, and DNA seem to be promising tools for the prognostication of recurrence after RC. Due to the high heterogeneity between the studies and the different cut-off values of biomarkers, prospective and validation trials with larger sample sizes and standardized cut-off values should be conducted to strengthen the approach in using biomarkers as a tool for risk stratification in clinical decision-making for patients with localized muscle-invasive BCa.

Molecular intricacies of upper tract urothelial carcinoma and their relevance for therapy considerations.

PURPOSE OF REVIEW: The aim of this study was to give an overview of molecular alterations in upper tract urothelial carcinomas (UTUCs) and to discuss them in the context of current and prospective systemic therapies. RECENT FINDINGS: UTUCs not only share a similar molecular landscape with urothelial carcinoma of the bladder (UCB), but also have distinct molecular features that can have an impact on therapy selection. FGFR3 alterations occur with a significant higher frequency in UTUC, with up to 40% of tumours harbouring FGFR3 driver mutations compared with 20% in UCB. In addition, a substantial number of high-grade UTUC show an immune-depleted phenotype and a luminal papillary expression subtype, thus predisposing them for FGFR inhibitor treatment. Approximately 20% of UTUC tumours have acquired mutations in TP53 and demonstrate a significant degree of genomic instability, which makes them candidates for systemic chemotherapy or immunotherapy. Whereas microsatellite instability (MSI) is rare in sporadic UTUC, 5-10% of UTUC patients have germline mutations in DNA mismatch repair genes, which leads to high MSI with enriched neoantigen load and presumably better response rates to immunotherapy. SUMMARY: Treatment decisions in UTUC should take molecular tumour characteristics into account. The currently most therapy-relevant molecular alterations in UTUC comprise FGFR3 mutational status and mutations in DNA mismatch repair genes with concomitant microsatellite instability.

Basal cell carcinoma of the prostate: a case report responding to the FGFR inhibitor pemigatinib and literature review.

PURPOSE OF REVIEW: Due to the limited number of cases, there are no guidelines for basal cell carcinoma (BCC) of the prostate. This review combines an unpublished case report of a 55-year-old patient with BCC with an assessment of the latest literature. RECENT FINDINGS: BCC of the prostate has previously been described in only approximately 140 cases. We describe the diagnostic process, including the uropathological and DNA-sequencing results, which allowed us to start an experimental treatment with pemigatinib. BCC of the prostate is associated with an aggressive biological and clinical behavior, such as recurrence and metastasis. Several immunohistochemical stainings are available to differentiate BCC from adenocarcinoma of the prostate. Based on pathology and results from next-generation sequencing (NGS), patients can be offered targeted therapies. SUMMARY: With the aid of histological work-up and immunostaining, prostatic BCC can be accurately diagnosed. Our patient underwent radical prostatectomy and staged extended lymphadenectomy due to lymph node recurrence. The patient subsequently developed progressive disease and was treated with the FGFR-inhibitor pemigatinib. The patient's liver metastasis significantly responded. The present case confirms the possibility of aggressive behavior of prostatic BCC and highlights the importance of a thorough uropathological and molecular biological analysis with a precision medicine strategy.

Molecular uropathology and cancer genetics for the urologist: key findings for classification and diagnosis.

PURPOSE OF REVIEW: To highlight the latest changes in prostate cancer (PCa), urothelial carcinoma, upper tract urothelial carcinoma (UTUC) and renal cell carcinoma (RCC) diagnosis and the impact of genetics in this field. RECENT FINDINGS: Breast cancer1/2 mutations start to play a major role in PCa treatment with regard to personalized medicine. In urothelial carcinoma an overlap between histological pathological and molecular findings exists, fibroblast growth factor receptor alteration are starting to play a major role, programmed death-ligand 1 although problematic is still important in the treatment setting. UTUC is rare, but genetically different from urothelial carcinoma. In the development of RCC, different genetic pathways such as Von Hippel-Lindau, but also tuberous sclerosis 1/2 and others play a major role in tumor development. SUMMARY: Over the last years, genetics has become increasingly important role in the diagnosis and the treatment of patients with urological malignancies. The upcoming 5th edition (1) of the WHO still considers conventional surgical pathology as the diagnostic gold standard, but molecular pathology is gaining importance not only for diagnosis, but also in personalized treatment, of prostate, kidney cancer and urothelial carcinomas. Therefore, a close collaboration between surgical urology, pathology and oncology departments is mandatory. In this review, we will discuss the latest evolutions in PCa, urothelial carcinoma, upper urinary tract carcinomas and RCC s in the field of genetics in urology.

Thyroid and androgen receptor signaling are antagonized by µ-Crystallin in prostate cancer.

Androgen deprivation therapy (ADT) remains a key approach in the treatment of prostate cancer (PCa). However, PCa inevitably relapses and becomes ADT resistant. Besides androgens, there is evidence that thyroid hormone thyroxine (T4) and its active form 3,5,3'-triiodo-L-thyronine (T3) are involved in the progression of PCa. Epidemiologic evidences show a higher incidence of PCa in men with elevated thyroid hormone levels. The thyroid hormone binding protein µ-Crystallin (CRYM) mediates intracellular thyroid hormone action by sequestering T3 and blocks its binding to cognate receptors (TRα/TRß) in target tissues. We show in our study that low CRYM expression levels in PCa patients are associated with early biochemical recurrence and poor prognosis. Moreover, we found a disease stage-specific expression of CRYM in PCa. CRYM counteracted thyroid and androgen signaling and blocked intracellular choline uptake. CRYM inversely correlated with [18F]fluoromethylcholine (FMC) levels in positron emission tomography/magnetic resonance imaging of PCa patients. Our data suggest CRYM as a novel antagonist of T3- and androgen-mediated signaling in PCa. The role of CRYM could therefore be an essential control mechanism for the prevention of aggressive PCa growth.

Poly(ADP-ribose) polymerase inhibitors in prostate and urothelial cancer.

PURPOSE OF REVIEW: The aim of this article is to give an overview of poly(ADP-ribose) polymerase inhibitors (PARPis) trials in prostate cancer and to discuss emerging approaches with potential future clinical implementation in both prostate and urothelial cancer. RECENT FINDINGS: PARPis are a class of drugs that can be applied for the treatment of homologous recombination repair (HRR)-deficient tumors. Tumors are potentially sensitive to PARPi harbor mutations in genes relevant for DNA damage repair, such as BRCA1/2 or ATM, which are present to a significant degree in metastatic prostate and urothelial cancer patients. Several PARPis have been successfully tested in clinical trials for HRR-deficient metastatic castration-resistant prostate cancer (mCRPC), and olaparib and rucaparib have recently received breakthrough approval in BRCA1/2 mutated mCRPC. Combination treatment of PARPis with androgen-receptor inhibitors or with checkpoint inhibitors and earlier frontline applications are currently being evaluated, and clinical trials enrolling bladder cancer (BCa) patients with HRR deficiency have recently been initiated. SUMMARY: Approximately 10% of mCRPC patients and 34% of metastatic BCa patients have tumors with HRR deficiency and may benefit from PARPi treatment. Correct identification of these patients as well as determining the most adequate time point for drug administration will be key to successful clinical implementation.

PD1/PD-L1 therapy in metastatic renal cell carcinoma.

PURPOSE OF REVIEW: The aim of the article to summarize recent changes of treatment options in metastatic renal cell carcinoma (mRCC) with a special emphasis on immune checkpoint inhibition. RECENT FINDINGS: The introduction of checkpoint inhibitor (CPI) therapy has led to a paradigm change in advanced renal cell carcinoma (RCC). Dual immune checkpoint inhibition or the combination of CPI and tyrosine kinase inhibitors (TKIs) was shown to improve survival when compared with the former standard of care sunitinib. Moreover, these novel strategies were shown to enable unprecedented rates of complete and durable responses, particularly with dual checkpoint inhibition. Although the treatment landscape has rapidly evolved, it remains unknown which combination is the best for the individual patient. Pivotal trials have used sunitinib as a comparator but no head to head comparisons have been conducted between novel agents so far. Moreover, no predictive biomarker has been identified yet to bring the best treatment to the individual patient. SUMMARY: The aim of this review is to summarize the findings of CPI-based trials conducted in RCC and to discuss the future of mRCC treatment.

Epigenetic alterations of testicular germ cell tumours.

PURPOSE OF REVIEW: Testicular germ cell tumours (TGCTs) exhibit, in contrast to other cancer types, a relatively low mutational burden. However, numerous epigenetic alterations have been shown to impact TGCT. In this review, we summarize the most relevant findings of the past 2 years. RECENT FINDINGS: Recent studies focused on the functions of microRNAs and the impact of aberrant DNA methylation. Moreover, several epigenetic drugs with antineoplastic effects in TGCTs were identified. SUMMARY: Aberrant DNA methylation and differentially expressed microRNAs have an important effect on TGCT pathogenesis. Moreover, differential DNA methylation patterns were found to be specific for different TGCT subtypes. Various microRNAs, such as miR-371a-3p, were found to be highly sensitive and specific biomarkers for TGCT. The epigenetic drugs guadecitabine, animacroxam, and JQ1 showed promising effects on TGCT in preclinical in-vivo and in-vitro studies.

The prognostic impact of tumour NSD2 expression in advanced prostate cancer.

Purpose: To assess the prognostic significance of the nuclear receptor binding SET protein 2 (NSD2), a co-activator of the NFkB-pathway, on tumour progression in patients with advanced prostate cancer (PCa).Methods: We retrospectively assessed NSD2 expression in 53 patients with metastatic and castration-resistant PCa. Immunohistochemical staining for NSD2 was carried out on specimen obtained from palliative resection of the prostate. Univariable and multivariable analyses were performed to assess the association between NSD2 expression and PCa progression.Results: Of the 53 patients, 41 had castration-resistant PCa and 48 men had metastases at time of tissue acquisition. NSD2 expression was increased in tumour specimen from 42 patients (79.2%). In univariable Cox regression analyses, NSD2 expression was associated with PSA progression, progression on imaging and overall survival (p = 0.04, respectively). In multivariable analyses, NSD2 expression did not retain its association with these endpoints.Conclusions: NSD2 expression is abnormal in almost 80% of patients with advanced PCa. Expression levels of this epigenetic regulator are easily detected by immunohistochemistry while this biomarker exhibited prognostic value for PCa progression and death in univariable analysis. Further studies on NSD2 involvement in PCa proliferation, progression, metastasis and resistance mechanisms are needed.

Salvage therapeutic strategies for bacillus Calmette-Guerin failure.

PURPOSE OF REVIEW: To give an overview of current options for conservative treatment of patients failing intravesical bacillus Calmette-Guerin (BCG) and to discuss emerging approaches with potential future clinical applications. RECENT FINDINGS: Radical cystectomy is the standard-of-care for patients failing BCG therapy. In patients unfit or unwilling to undergo surgery, salvage therapy options could be proposed with the aim to offer local cancer control and prevent progression to muscle-invasive disease. Salvage treatments have been conducted using intravesical chemotherapy regimens, chemoradiation or chemohyperthermia. Intravesical agents such as valrubicin, gemcitabine or docetaxel showed response rates varying between 16 and 40%, whereas combination treatments of gemcitabine with docetaxel or mitomycin reported response rates in up to 50% of all patients with durable responses in about one out of three patients. For chemohyperthermia, 2-year recurrence rates between 41 and 56% have been reported. Ongoing clinical trials are evaluating chemoradiation as well as novel approaches such as systemic immunotherapy, viral gene therapy, targeted therapy or vaccination strategies with promising preliminary outcomes. SUMMARY: Salvage therapeutic bladder-sparing strategies for BCG failure such as intravesical chemotherapy or chemoradiation should currently only be considered in patients unfit for or refusing surgery. Innovative concepts such as chemohyperthermia, checkpoint inhibitors, targeted therapy or viral gene therapy could lead to major changes in clinical management of BCG failures in the future.

The mitochondrial carrier Rim2 co-imports pyrimidine nucleotides and iron.

Mitochondrial iron uptake is of key importance both for organelle function and cellular iron homoeostasis. The mitochondrial carrier family members Mrs3 and Mrs4 (homologues of vertebrate mitoferrin) function in organellar iron supply, yet other low efficiency transporters may exist. In Saccharomyces cerevisiae, overexpression of RIM2 (MRS12) encoding a mitochondrial pyrimidine nucleotide transporter can overcome the iron-related phenotypes of strains lacking both MRS3 and MRS4. In the present study we show by in vitro transport studies that Rim2 mediates the transport of iron and other divalent metal ions across the mitochondrial inner membrane in a pyrimidine nucleotide-dependent fashion. Mutations in the proposed substrate-binding site of Rim2 prevent both pyrimidine nucleotide and divalent ion transport. These results document that Rim2 catalyses the co-import of pyrimidine nucleotides and divalent metal ions including ferrous iron. The deletion of RIM2 alone has no significant effect on mitochondrial iron supply, Fe-S protein maturation and haem synthesis. However, RIM2 deletion in mrs3/4Δ cells aggravates their Fe-S protein maturation defect. We conclude that under normal physiological conditions Rim2 does not play a significant role in mitochondrial iron acquisition, yet, in the absence of the main iron transporters Mrs3 and Mrs4, this carrier can supply the mitochondrial matrix with iron in a pyrimidine-nucleotide-dependent fashion.

Identification of differential and functionally active miRNAs in both anaplastic lymphoma kinase (ALK)+ and ALK- anaplastic large-cell lymphoma.

Aberrant anaplastic lymphoma kinase (ALK) expression is a defining feature of many human cancers and was identified first in anaplastic large-cell lymphoma (ALCL), an aggressive non-Hodgkin T-cell lymphoma. Since that time, many studies have set out to identify the mechanisms used by aberrant ALK toward tumorigenesis. We have identified a distinct profile of micro-RNAs (miRNAs) that characterize ALCL; furthermore, this profile distinguishes ALK(+) from ALK(-) subtypes, and thus points toward potential mechanisms of tumorigenesis induced by aberrant ALK. Using a nucleophosmin-ALK transgenic mouse model as well as human primary ALCL tumor tissues and human ALCL-derived cell lines, we reveal a set of overlapping deregulated miRNAs that might be implicated in the development and progression of ALCL. Importantly, ALK(+) and ALK(-) ALCL could be distinguished by a distinct profile of "oncomirs": Five members of the miR-17-92 cluster were expressed more highly in ALK(+) ALCL, whereas miR-155 was expressed more than 10-fold higher in ALK(-) ALCL. Moreover, miR-101 was down-regulated in all ALCL model systems, but its forced expression attenuated cell proliferation only in ALK(+) and not in ALK(-) cell lines, perhaps suggesting different modes of ALK-dependent regulation of its target proteins. Furthermore, inhibition of mTOR, which is targeted by miR-101, led to reduced tumor growth in engrafted ALCL mouse models. In addition to future therapeutical and diagnostic applications, it will be of interest to study the physiological implications and prognostic value of the identified miRNA profiles.

Treatment Patterns and Real-World Outcomes for Locally Advanced or Metastatic Urothelial Cancer in the Era of Immunotherapy.

BACKGROUND AND OBJECTIVE: There are limited data on real-world outcomes for patients with advanced or metastatic urothelial cancer (mUC) since immune checkpoint inhibitors (ICIs) became available. Our objective was to analyze outcomes for patients with mUC since ICIs became available. METHODS: We performed a retrospective analysis of 131 patients with mUC attending the outpatient clinic of a single tertiary care center who received systemic therapy between June 2017 and July 2021 with follow-up up to December 2022. Summary and descriptive statistics were calculated for categorical and continuous variables. The Kaplan-Meier method was applied to calculate survival, and a Cox proportional-hazards model was used to explore associations between clinical variables and outcomes. KEY FINDINGS AND LIMITATIONS: The median patient age was 68 yr (range 35-90). The first systemic therapy administered was platinum-based in 79% of cases and ICI-based in 21%. Some 61% of the cohort received a second systemic treatment, with 75% of these an ICI. Median overall survival for the entire cohort was 24 mo (interquartile range 9-35). Patients on ICI therapy for ≥6 mo had median overall survival of 59 mo (95% confidence interval 39 mo-not reached). Metastatic sites on initiation of ICI therapy and C-reactive protein kinetics were prognostic in patients receiving ICIs. Limitations include the retrospective design and inherent selection bias. CONCLUSIONS AND CLINICAL IMPLICATIONS: More than 60% of patients with mUC received second-line treatment, and 75% of these received an ICI. Patients staying on immunotherapy for more than 6 mo have substantially better outcomes in comparison to patients with less time on immunotherapy and historical cohorts. PATIENT SUMMARY: We looked at the lines of therapy and outcomes for patients with advanced or metastatic cancer of the urinary tract, starting from when immunotherapy drugs called immune checkpoint inhibitors (ICIs) became available. We found that 60% of patients have received second-line therapy, which is a double the rate in comparison to historical groups of patients. Patients with long-term ICI therapy (>6 months) had significantly better outcomes, with a median survival of more than 3 years.

Quantitative Acetylomics Uncover Acetylation-Mediated Pathway Changes Following Histone Deacetylase Inhibition in Anaplastic Large Cell Lymphoma.

Histone deacetylases (HDACs) target acetylated lysine residues in histone and non-histone proteins. HDACs are implicated in the regulation of genomic stability, cell cycle, cell death and differentiation and thus critically involved in tumorigenesis. Further, HDACs regulate T-cell development and HDAC inhibitors (HDACis) have been approved for clinical use in some T-cell malignancies. Still, the exact targets and mechanisms of HDAC inhibition in cancer are understudied. We isolated tumor cell lines from a transgenic mouse model of anaplastic large cell lymphoma (ALCL), a rare T-cell lymphoma, and abrogated HDAC activity by treatment with the HDACis Vorinostat and Entinostat or Cre-mediated deletion of Hdac1. Changes in overall protein expression as well as histone and protein acetylation were measured following Hdac1 deletion or pharmacological inhibition using label-free liquid chromatography mass spectrometry (LC-MS/MS). We found changes in overall protein abundance and increased acetylation of histones and non-histone proteins, many of which were newly discovered and associated with major metabolic and DNA damage pathways. For non-histone acetylation, we mapped a total of 1204 acetylated peptides corresponding to 603 proteins, including chromatin modifying proteins and transcription factors. Hyperacetylated proteins were involved in processes such as transcription, RNA metabolism and DNA damage repair (DDR). The DDR pathway was majorly affected by hyperacetylation following HDAC inhibition. This included acetylation of H2AX, PARP1 and previously unrecognized acetylation sites in TP53BP1. Our data provide a comprehensive view of the targets of HDAC inhibition in malignant T cells with general applicability and could have translational impact for the treatment of ALCL with HDACis alone or in combination therapies.

Circulating Tumour DNA Is a Strong Predictor of Outcomes in Patients Treated with Systemic Therapy for Urothelial Carcinoma.

We summarise the available data for and assess the prognostic value of circulating tumour DNA (ctDNA) in patients treated with systemic therapy for urothelial carcinoma (UC). Studies were deemed eligible if they reported on oncologic outcomes for patients with UC treated with systemic therapy according to the baseline ctDNA profile (before starting systemic therapy) and/or changes over the course of therapy. Five studies met the eligibility criteria. We found a strong association between high baseline ctDNA levels and worse disease-free survival (DFS; hazard ratio [HR] 3.53, 95% confidence interval [CI] 2.58-4.84) and overall survival (OS; HR 2.99, 95% CI 2.17-4.13). Patients with a decline in ctDNA level after immunotherapy had better DFS (HR 0.25, 95% CI 0.13-0.49) and OS (HR 0.10, 95% CI 0.03-0.42) in comparison to patients without a ctDNA decline. Conversely, an increase in ctDNA levels after immunotherapy was associated with worse survival outcomes. Patients with UC who exhibited a decrease in ctDNA levels during systemic therapy had better survival outcomes compared to those with stable or increasing ctDNA levels. PATIENT SUMMARY: Measurement of tumour DNA in blood may help in identifying patients with cancer of the urinary tract who are unlikely to respond to chemotherapy or immunotherapy. This could serve as a biomarker for monitoring cancer treatment.

Evaluation of APOBEC3 expression as prognostic marker in squamous cell carcinoma of the penis.

Squamous cell carcinoma of the penis (PSC) is a rare disease with limited information on the molecular events leading to malignant transformation. In a third of PSC cases, presence of human papilloma virus (HPV) is found. The APOBEC3 family of proteins is known to play a significant role in defense against HPV infection, but their role in PSC is largely unknown. In this study, we aim to assess mRNA expression levels of APOBEC3 family members in HPV+ and HPV- PSC to get insight into their association with clinicopathological features and to evaluate their prognostic impact. Expression levels of six APOBEC3 family members in tissue from 50 patients with PSC were determined by RT-PCR and correlated with clinical and histopathological features. Lower expression of APOBEC3A, APOBEC3B, and APOBEC3C was observed in advanced PSC stages. Except for APOBEC3D, HPV+ samples showed higher expression of APOBEC3s compared to HPV- samples. In univariate analyses, APOBEC3A and APOBEC3C expression tended to be associated with disease-free survival and APOBEC3A expression with overall survival; however, multivariable analyses failed to confirm these associations with outcome. More extensive external validation and functional laboratory studies are needed to evaluate further their role in PSC development and progression.

Molecular and Pharmacological Bladder Cancer Therapy Screening: Discovery of Clofarabine as a Highly Active Compound.

BACKGROUND: The heterogeneity of bladder cancers (BCs) is a major challenge for the development of novel therapies. However, given the high rates of recurrence and/or treatment failure, the identification of effective therapeutic strategies is an urgent clinical need. OBJECTIVE: We aimed to establish a model system for drug identification/repurposing in order to identify novel therapies for the treatment of BC. DESIGN, SETTING, AND PARTICIPANTS: A collection of commercially available BC cell lines (n = 32) was comprehensively characterized. A panel of 23 cell lines, representing a broad spectrum of BC, was selected to perform a high-throughput drug screen. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Positive hits were defined as compounds giving >50% inhibition in at least one BC cell line. RESULTS AND LIMITATIONS: Amongst >1700 tested chemical compounds, a total of 471 substances exhibited antineoplastic effects. Clofarabine, an antimetabolite drug used as third-line treatment for childhood acute lymphoblastic leukaemia, was amongst the limited number of drugs with inhibitory effects on cell lines of all intrinsic subtypes. We, thus, reassessed the substance and confirmed its inhibitory effects on commercially available cell lines and patient-derived cell cultures representing various disease stages, intrinsic subtypes, and histologic variants. To verify these effects in vivo, a patient-derived cell xenograft model for urothelial carcinoma (UC) was used. Well-tolerated doses of clofarabine induced complete remission in all treated animals (n = 12) suffering from both early- and late-stage disease. We further took advantage of another patient-derived cell xenograft model originating from the rare disease entity sarcomatoid carcinoma (SaC). Similarly to UC xenograft mice, clofarabine induced subcomplete to complete tumour remissions in all treated animals (n = 8). CONCLUSIONS: The potent effects of clofarabine in vitro and in vivo suggest that our findings may be of high clinical relevance. Clinical trials are needed to assess the value of clofarabine in improving BC patient care. PATIENT SUMMARY: We used commercially available cell lines for the identification of novel drugs for the treatment of bladder cancer. We confirmed the effects of one of these drugs, clofarabine, in patient-derived cell lines and two different mouse models, thereby demonstrating a potential clinical relevance of this substance in bladder cancer treatment.