Clofarabine Has a Superior Therapeutic Window as compared to Gemcitabine in Preclinical Bladder Cancer Models

Current standard-of-care systemic therapy options for locally advanced and metastatic bladder cancer (BC), which are predominantly based on cisplatin-gemcitabine combinations, are limited by significant treatment failure rates and frailty-based patient ineligibility. We previously addressed the urgent clinical need for better-tolerated BC therapeutic strategies using a drug screening approach, which identified outstanding antineoplastic activity of clofarabine in preclinical models of BC. To further assess clofarabine as a potential BC therapy component, we conducted head-to-head comparisons of responses to clofarabine versus gemcitabine in preclinical in vitro and in vivo models of BC, complemented by in silico analyses. In vitro data suggest a distinct correlation between the two antimetabolites, with higher cytotoxicity of gemcitabine, especially against several nonmalignant cell types, including keratinocytes and endothelial cells. Accordingly, tolerance of clofarabine (oral or intraperitoneal application) was distinctly better than for gemcitabine (intraperitoneal) in patient-derived xenograft models of BC. Clofarabine also exhibited distinctly superior anticancer efficacy, even at dosing regimens optimized for gemcitabine. Neither complete remission nor cure, both of which were observed with clofarabine, were achieved with any tolerable gemcitabine regimen. Taken together, our findings demonstrate that clofarabine has a better therapeutic window than gemcitabine, further emphasizing its potential as a candidate for drug repurposing in BC. PATIENT SUMMARY: We compared the anticancer activity of clofarabine, a drug used for treatment of leukemia but not bladder cancer, and gemcitabine, a drug currently used for chemotherapy against bladder cancer. Using cell cultures and mouse models, we found that clofarabine was better tolerated and more efficacious than gemcitabine, and even cured implanted tumors in mouse models. Our results suggest that clofarabine, alone or in combination schemes, might be superior to gemcitabine for the treatment of bladder cancer.

Metastatic Translocated Renal Cell Carcinoma in a Kidney Transplant Patient - a Case Report and Review of the Literature

TFEB-altered renal cell carcinomas are rare tumours. Here, we report the exceptional case of such a tumour in the setting of solid organ transplantation and with already metastatic disease at the time of diagnosis. The primary tumour occurred in the native kidney and only focally showed biphasic morphology whereas the metastasis, among others to the transplant kidney, showed nonspecific, albeit different morphology, but both had consistent TFEB translocation. Treatment with the immune checkpoint inhibitor pembrolizumab together with the multi-kinase inhibitor lenvatinib achieved partial response 14 months after diagnosis.

Clinical Management of Intraductal Carcinoma of the Prostate

Intraductal carcinoma of the prostate (IDC-P) has emerged as a distinct entity with significant clinical implications in prostate cancer (PCa) management. Despite historically being considered an extension of invasive PCa, IDC-P shows unique biological characteristics that challenge traditional diagnostic and therapeutic settings. This review explores the clinical management of IDC-P. While the diagnosis of IDC-P relies on specific morphological criteria, its detection remains challenging due to inter-observer variability. Emerging evidence underscores the association of IDC-P with aggressive disease and poor clinical outcomes across various PCa stages. However, standardized management guidelines for IDC-P are lacking. Recent studies suggest considering adjuvant and neoadjuvant therapies in specific patient cohorts to improve outcomes and tailor treatment strategies based on the IDC-P status. However, the current level of evidence regarding this is low. Moving forward, a deeper understanding of the pathogenesis of IDC-P and its interaction with conventional PCa subtypes is crucial for refining risk stratification and therapeutic interventions.

Clinical parameters for the prediction of occult lymph node metastasis in patients with negative PSMA-PET

BACKGROUND

Depending on the risk of LN metastasis ePLND at RP is recommended. As ePLND has potential side effects, and diagnostics have improved substantially, our objective was to evaluate the performance of the Briganti 2019 nomogram in a contemporary cohort with preoperative negative PSMA-PET.

METHODS

Patients with intermediate- and high-risk prostate cancer (CaP), undergoing RP and ePND at our center with preoperative negative [68Ga]Ga-PSMA-11 PET were included. The Accuracy of the nomogram was assessed using ROC analysis. The association of clinical parameters with the presence of LN metastasis was assessed using logistic regression. Specimen of prostate and LNs in patients with false negative PSMA-PET were additionally stained for AR and PSMA expression and assessed by IHC.

RESULTS

The study included 108 patients, 28% intermediate- and 72% high-risk. Twelve patients harbored occult LN metastasis. Accuracy of the nomogram was 0.62. [68Ga]Ga-PSMA-11 PET showed a NPV of 89%. IHC showed expression of PSMA and AR in the primary and LN metastasis in all patients. On logistic regression analysis only DRE (OR 2.72; 95%CI 1.01-7.35; P = 0.05) and percentage of cores with significant CaP (OR 1.29; 95%CI 1.05-1.60; P = 0.02) showed a significant association with LN metastasis.

CONCLUSION

The currently used nomogram is suboptimal in detecting patients with occult LNM. While the cut-off value to perform ePLND can be increased slightly following a negative PSMA-PET scan, more accurate methods of identifying these patients are needed. Whether ePLND can have a therapeutic benefit, as opposed to a diagnostic only, needs to be re-evaluated in the PSMA-PET era.

Update on classification of oncocytic neoplasms of the kidney

PURPOSE OF REVIEW

This review provides a summary of recent developments in classification of renal oncocytic neoplasms that were incorporated in the fifth edition WHO classification of renal tumors, released in 2022.

RECENT FINDINGS

Besides the distinct entities of renal oncocytoma and chromophobe renal cell carcinoma, the WHO now acknowledges a heterogeneous group of oncocytic tumors of the kidney that can be reported as 'oncocytic renal neoplasms of low malignant potential'. Case series by multiple institutions have revealed recurrent patterns of morphological features, protein marker expression, and genetic alterations within these neoplasms that may permit further subclassification in the future.

SUMMARY

The new classification system provides pathologists with the opportunity to simplify the diagnostic workup and reporting of morphologically equivocal oncocytic neoplasms.

Mitosis domain generalization in histopathology images - The MIDOG challenge

The density of mitotic figures (MF) within tumor tissue is known to be highly correlated with tumor proliferation and thus is an important marker in tumor grading. Recognition of MF by pathologists is subject to a strong inter-rater bias, limiting its prognostic value. State-of-the-art deep learning methods can support experts but have been observed to strongly deteriorate when applied in a different clinical environment. The variability caused by using different whole slide scanners has been identified as one decisive component in the underlying domain shift. The goal of the MICCAI MIDOG 2021 challenge was the creation of scanner-agnostic MF detection algorithms. The challenge used a training set of 200 cases, split across four scanning systems. As test set, an additional 100 cases split across four scanning systems, including two previously unseen scanners, were provided. In this paper, we evaluate and compare the approaches that were submitted to the challenge and identify methodological factors contributing to better performance. The winning algorithm yielded an F₁ score of 0.748 (CI95: 0.704-0.781), exceeding the performance of six experts on the same task.

Consecutive PSMA and AR PET imaging shows positive correlation to AR and PSMA protein expression in primary hormone naïve prostate cancer

Rationale: The present study set out to investigate if PET imaging can be used as a potential substitute for immunohistochemical analysis of tumor samples in prostate cancer (PC) patients. Correlation between imaging signals of two PET tracers and the corresponding target structures was assessed. The first tracer was [⁶⁸Ga]Ga-PSMAHBED-CC([⁶⁸Ga]PSMA), which is already implemented in clinical routine. The second tracer was [¹⁸F]-fluoro-5α-dihydrotestosterone([¹⁸F]FDHT) which binds to the androgen receptor (AR). The AR is particularly interesting in PC, since the AR expression status and its shift during therapy might directly influence patient care. Methods: This prospective, explorative clinical study included 10 newly diagnosed PC patients. Each patient received a [⁶⁸Ga]PSMA-PET/MRI- and [¹⁸F]FDHT-PET/MRI-scan prior to prostatectomy. Cancer standardized uptake values (SUV) were determined and related to background SUVs. Following prostatectomy, tumor tissue was sampled and AR and prostate-specific membrane antigen (PSMA) expression determined. AR and PSMA expressions were evaluated quantitively with QuPath and additionally with a four-tiered rating system. Correlation between imaging signals and marker expression was statistically assessed. Results: For [¹⁸F]FDHT, the SUV_max/SUVbackground ratio showed a significant, strong correlation (P-value=0.019, r=0.72) with AR optical density of the correlating tissue sample. The correlation between PSMA optical density and the [⁶⁸Ga]PSMA SUV_max/SUVbackground ratio was not significant (P-value=0.061), yet a positive correlation trend could be observed (r=0.61). SUV_max/SUVbackground ratios were higher for [⁶⁸Ga]PSMA (34.9±24.8) compared to [¹⁸F]FDHT (4.8±1.2). In line with this findings, the tumor detection rate of the Ga-PSMA-PET scan was 90%, but only 40% for the [¹⁸F]FDHT-PET scan. The four-tiered rating of PSMA staining intensity yielded very homogenous results with values of 3+ for most subjects (90%). The AR staining was rated with 1+ in two patients (20%), with 2+ in four patients (40%) and with 3+ in four patients (40%). Conclusion: [¹⁸F]FDHT-PET may be useful for monitoring AR expression and alterations of AR expression during treatment of PC patients. This may facilitate early detection of treatment resistance and allows for adaptation of therapy to prevent cancer progression. [¹⁸F]FDHT-PET is inferior to [⁶⁸Ga]PSMA-PET for primary PC diagnosis, but the correlation between [⁶⁸Ga]PSMA SUVs and PSMA expression is weaker compared to [¹⁸F]FDHT and the AR.

Update on Flat and Papillary Urothelial Lesions: Genitourinary Pathology Society Consensus Recommendations

The reporting recommendations on "flat and papillary urothelial neoplasia," published in 2 position articles by the Genitourinary Pathology Society in July 2021, was a collective contribution of 38 multidisciplinary experts aiming to clarify nomenclature, classification of flat and papillary urothelial neoplasia and controversial issues. In this review, we discuss some of these recommendations including nomenclature, practical approaches, and their importance for clinical practice.

A novel molecular signature identifies mixed subtypes in renal cell carcinoma with poor prognosis and independent response to immunotherapy

Background

Renal cell carcinoma (RCC) is a heterogeneous disease comprising histologically defined subtypes. For therapy selection, precise subtype identification and individualized prognosis are mandatory, but currently limited. Our aim was to refine subtyping and outcome prediction across main subtypes, assuming that a tumor is composed of molecular features present in distinct pathological subtypes.

Methods

Individual RCC samples were modeled as linear combination of the main subtypes (clear cell (ccRCC), papillary (pRCC), chromophobe (chRCC)) using computational gene expression deconvolution. The new molecular subtyping was compared with histological classification of RCC using the Cancer Genome Atlas (TCGA) cohort (n = 864; ccRCC: 512; pRCC: 287; chRCC: 65) as well as 92 independent histopathologically well-characterized RCC. Predicted continuous subtypes were correlated to cancer-specific survival (CSS) in the TCGA cohort and validated in 242 independent RCC. Association with treatment-related progression-free survival (PFS) was studied in the JAVELIN Renal 101 (n = 726) and IMmotion151 trials (n = 823). CSS and PFS were analyzed using the Kaplan–Meier and Cox regression analysis.

Results

One hundred seventy-four signature genes enabled reference-free molecular classification of individual RCC. We unambiguously assign tumors to either ccRCC, pRCC, or chRCC and uncover molecularly heterogeneous tumors (e.g., with ccRCC and pRCC features), which are at risk of worse outcome. Assigned proportions of molecular subtype-features significantly correlated with CSS (ccRCC (P = 4.1E − 10), pRCC (P = 6.5E − 10), chRCC (P = 8.6E − 06)) in TCGA. Translation into a numerical RCC-R(isk) score enabled prognosis in TCGA (P = 9.5E − 11). Survival modeling based on the RCC-R score compared to pathological categories was significantly improved (P = 3.6E − 11). The RCC-R score was validated in univariate (P = 3.2E − 05; HR = 3.02, 95% CI: 1.8–5.08) and multivariate analyses including clinicopathological factors (P = 0.018; HR = 2.14, 95% CI: 1.14–4.04). Heterogeneous PD-L1-positive RCC determined by molecular subtyping showed increased PFS with checkpoint inhibition versus sunitinib in the JAVELIN Renal 101 (P = 3.3E − 04; HR = 0.52, 95% CI: 0.36 − 0.75) and IMmotion151 trials (P = 0.047; HR = 0.69, 95% CI: 0.48 − 1). The prediction of PFS significantly benefits from classification into heterogeneous and unambiguous subtypes in both cohorts (P = 0.013 and P = 0.032).

Conclusion

Switching from categorical to continuous subtype classification across most frequent RCC subtypes enables outcome prediction and fosters personalized treatment strategies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13073-022-01105-y.

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.

PD-L1 (SP142) testing is concordant between Benchmark Ultra and Bond-III stainers

Background

Atezolizumab is an inhibitor of programmed death-ligand 1 (PD-L1), used to treat advanced or metastatic bladder cancer, and in trials for non-invasive disease. In order to be eligible for treatment, patients require a PD-L1 immune cell score ≥ 5%, using the Ventana SP142 PD-L1 assay. Many laboratories do not have access to the required Ventana Benchmark Ultra stainer, and it is unclear if the assay performs similarly on other stainers. In this study, we compare SP142 assay results between Ventana Benchmark Ultra and Leica Bond-III stainers.

Methods

Serial sections of 90 samples of transurethral bladder resections (comprising 51 pTaHG, 8 pTis, 18 pT1, 10 pT2 tumors) were stained using the SP142 PD-L1 antibody on Ventana Benchmark Ultra and Leica Bond-III stainers, manually scored, and compared using accuracy and Cohen’s kappa measures.

Results

Both devices yielded highly concordant PD-L1 immune cell scores (accuracy 0.84, Cohen’s κ 0.732). Moreover, we found similar tumor cell (TC) PD-L1 scores using both stainers, and a trend towards greater TC scores in pT2 stage samples (p = 0.05).

Conclusion

This study is the first to compare the SP142 antibody in bladder cancer on two different stainers. Our results indicate that both Benchmark Ultra and Bond-III stainers yield highly concordant results using the SP142 PD-L1 antibody.

Artificial intelligence in prostate histopathology: where are we in 2021?

PURPOSE OF REVIEW

Artificial intelligence has made an entrance into mainstream applications of daily life but the clinical deployment of artificial intelligence-supported histological analysis is still at infancy. Recent years have seen a surge in technological advance regarding the use of artificial intelligence in pathology, in particular in the diagnosis of prostate cancer.

RECENT FINDINGS

We review first impressions of how artificial intelligence impacts the clinical performance of pathologists in the analysis of prostate tissue. Several challenges in the deployment of artificial intelligence remain to be overcome. Finally, we discuss how artificial intelligence can help in generating new knowledge that is interpretable by humans.

SUMMARY

It is evident that artificial intelligence has the potential to outperform most pathologists in detecting prostate cancer, and does not suffer from inherent interobserver variability. Nonetheless, large clinical validation studies that unequivocally prove the benefit of artificial intelligence support in pathology are necessary. Regardless, artificial intelligence may soon automate and standardize many facets of routine work, including qualitative (i.e. Gleason Grading) and quantitative measures (i.e. portion of Gleason Grades and tumor volume). For the near future, a model where pathologists are enhanced by second-review or real-time artificial intelligence systems appears to be the most promising approach.

Pathological reporting of cystectomy lymph nodes: a retrospective analysis of experience in Paris

Purpose

Pathological evaluation of pelvic lymph node (LN) dissection (PLND) is important for management of cystectomy patients. However, challenges such as unclear interobserver variability of LN counting remain. Here, we assess interobserver variability of LN measures and their clinical utility, with a focus on variant histology.

Methods

We retrieved radical cystectomy cases with PLND between 2010 and 2016 and reevaluated pathological parameters; number of total and metastatic LN, LN density (LND), length of metastatic LN and metastases, extranodal extension (ENE).

Results

We report 96 patients: median age of 71a, 34 cases pN+, 36 cases with any extent of variant histology, median follow-up 10 months. Perivesical LN were only rarely identified, but frequently metastatic (4/9). Variant histology (34 cases) frequently exhibited LN metastasis (53% of pN+ cases). Interobserver variance was poor for total LN (kappa = 0.167), excellent for positive LN (0.85) and pN staging (0.96), and mediocre for LND (0.53). ROC analysis suggests that both LND and the sum of LN metastasis length may predict outcome (AUC 0.83 and 0.75, respectively).

Conclusion

Our study confirms the notion of LND as a prognostic measure, but cautions due to strong interobserver variance of LN counts. The sum length of LN metastases could be a measure that is independent of LN counts. We find that microscopically identified perivesical LN merit particular attention. In summary, our study highlights current challenges in pathological reporting of PLND, confirms previous observations and forms a basis for further studies.