HPV DNA Integration at Actionable Cancer-Related Genes Loci in HPV-Associated Carcinomas.

In HPV-associated carcinomas, some examples of cancer-related genes altered by viral insertion and corresponding to potential therapeutic targets have been described, but no quantitative assessment of these events, including poorly recurrent targets, has been reported to date. To document these occurrences, we built and analyzed a database comprised of 1455 cases, including HPV genotypes and tumor localizations. Host DNA sequences targeted by viral integration were classified as "non-recurrent" (one single reported case; 838 loci), "weakly recurrent" (two reported cases; 82 loci), and highly recurrent (≥3 cases; 43 loci). Whereas the overall rate of cancer-related target genes was 3.3% in the Gencode database, this rate increased to 6.5% in "non-recurrent", 11.4% in "weakly recurrent", and 40.1% in "highly recurrent" genes targeted by integration (p = 4.9 × 10-4). This rate was also significantly higher in tumors associated with high-risk HPV16/18/45 than other genotypes. Among the genes targeted by HPV insertion, 30.2% corresponded to direct or indirect druggable targets, a rate rising to 50% in "highly recurrent" targets. Using data from the literature and the DepMap 23Q4 release database, we found that genes targeted by viral insertion could be new candidates potentially involved in HPV-associated oncogenesis. A more systematic characterization of HPV/host fusion DNA sequences in HPV-associated cancers should provide a better knowledge of HPV-driven carcinogenesis and favor the development of personalize patient treatments.

Proteogenomic Characterization of Bladder Cancer Reveals Sensitivity to Apoptosis Induced by Tumor Necrosis Factor-related Apoptosis-inducing Ligand in FGFR3-mutated Tumors.

BACKGROUND: Molecular understanding of muscle-invasive (MIBC) and non-muscle-invasive (NMIBC) bladder cancer is currently based primarily on transcriptomic and genomic analyses. OBJECTIVE: To conduct proteogenomic analyses to gain insights into bladder cancer (BC) heterogeneity and identify underlying processes specific to tumor subgroups and therapeutic outcomes. DESIGN, SETTING, AND PARTICIPANTS: Proteomic data were obtained for 40 MIBC and 23 NMIBC cases for which transcriptomic and genomic data were already available. Four BC-derived cell lines harboring FGFR3 alterations were tested with interventions. INTERVENTION: Recombinant tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), second mitochondrial-derived activator of caspases mimetic (birinapant), pan-FGFR inhibitor (erdafitinib), and FGFR3 knockdown. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Proteomic groups from unsupervised analyses (uPGs) were characterized using clinicopathological, proteomic, genomic, transcriptomic, and pathway enrichment analyses. Additional enrichment analyses were performed for FGFR3-mutated tumors. Treatment effects on cell viability for FGFR3-altered cell lines were evaluated. Synergistic treatment effects were evaluated using the zero interaction potency model. RESULTS AND LIMITATIONS: Five uPGs, covering both NMIBC and MIBC, were identified and bore coarse-grained similarity to transcriptomic subtypes underlying common features of these different entities; uPG-E was associated with the Ta pathway and enriched in FGFR3 mutations. Our analyses also highlighted enrichment of proteins involved in apoptosis in FGFR3-mutated tumors, not captured through transcriptomics. Genetic and pharmacological inhibition demonstrated that FGFR3 activation regulates TRAIL receptor expression and sensitizes cells to TRAIL-mediated apoptosis, further increased by combination with birinapant. CONCLUSIONS: This proteogenomic study provides a comprehensive resource for investigating NMIBC and MIBC heterogeneity and highlights the potential of TRAIL-induced apoptosis as a treatment option for FGFR3-mutated bladder tumors, warranting a clinical investigation. PATIENT SUMMARY: We integrated proteomics, genomics, and transcriptomics to refine molecular classification of bladder cancer, which, combined with clinical and pathological classification, should lead to more appropriate management of patients. Moreover, we identified new biological processes altered in FGFR3-mutated tumors and showed that inducing apoptosis represents a new potential therapeutic option.

Establishment and Comprehensive Characterization of a Novel Preclinical Platform of Metastatic Retinoblastoma for Therapeutic Developments.

Purpose: Although there have been improvements in the management of metastatic retinoblastoma, most patients do not survive, and all patients suffer from multiple short- and long-term treatment toxicities. Reliable and informative models to assist clinicians are needed. Thus we developed and comprehensively characterized a novel preclinical platform of primary cell cultures and xenograft models of metastatic retinoblastoma to provide insights into the molecular biology underlying metastases and to perform drug screening for the identification of hit candidates with the highest potential for clinical translation. Methods: Orbital tumor, bone marrow, cerebrospinal fluid, and lymph node tumor infiltration specimens were obtained from seven patients with metastatic retinoblastoma at diagnosis, disease progression, or relapse. Tumor specimens were engrafted in immunodeficient animals, and primary cell lines were established. Genomic, immunohistochemical/immunocytochemical, and pharmacological analysis were performed. Results: We successfully established five primary cell lines: two derived from leptomeningeal, two from orbital, and one from lymph node tumor dissemination. After the intravitreal or intraventricular inoculation of these cells, we established cell-derived xenograft models. Both primary cell lines and xenografts accurately retained the histological and genomic features of the tumors from which they were derived and faithfully recapitulated the dissemination patterns and pharmacological sensitivity observed in the matched patients. Conclusions: Ours is an innovative and thoroughly characterized preclinical platform of metastatic retinoblastoma developed for the understanding of tumor biology of this highly aggressive tumor and has the potential to identify drug candidates to treat patients who currently lack effective treatment options.

Cohort profile: COBLAnCE: a French prospective cohort to study prognostic and predictive factors in bladder cancer and to generate real-world data on treatment patterns, resource use and quality of life.

PURPOSE: Bladder cancer is a complex disease with a wide range of outcomes. Clinicopathological factors only partially explain the variability between patients in prognosis and treatment response. There is a need for large cohorts collecting extensive data and biological samples to: (1) investigate gene-environment interactions, pathological/molecular classification and biomarker discovery; and (2) describe treatment patterns, outcomes, resource use and quality of life in a real-world setting. PARTICIPANTS: COBLAnCE (COhort to study BLAdder CancEr) is a French national prospective cohort of patients with bladder cancer recruited between 2012 and 2018 and followed for 6 years. Data on patient and tumour characteristics, treatments, outcomes and biological samples are collected at enrolment and during the follow-up. FINDINGS TO DATE: We describe the cohort at enrolment according to baseline surgery and tumour type. In total, 1800 patients were included: 1114 patients with non-muscle-invasive bladder cancer (NMIBC) and 76 patients with muscle-invasive bladder cancer (MIBC) had transurethral resection of a bladder tumour without cystectomy, and 610 patients with NMIBC or MIBC underwent cystectomy. Most patients had a solitary lesion (56.3%) without basement membrane invasion (71.7% of Ta and/or Tis). Half of the patients with cystectomy were stage ≤T2 and 60% had non-continent diversion. Surgery included local (n=298) or super-extended lymph node dissections (n=11) and prostate removal (n=492). Among women, 16.5% underwent cystectomy and 81.4% anterior pelvectomy. FUTURE PLANS: COBLAnCE will be used for long-term studies of bladder cancer with focus on clinicopathological factors and molecular markers. It will lead to a much-needed improvement in the understanding of the disease. The cohort provides valuable real-world data, enabling researchers to study various research questions, assess routine medical practices and guide medical decision-making.

A Case-Only Genome-Wide Interaction Study of Smoking and Bladder Cancer Risk: Results from the COBLAnCE Cohort.

Bladder cancer (BC) is the 6th most common cancer worldwide, with tobacco smoking considered as its main risk factor. Accumulating evidence has found associations between genetic variants and the risk of BC. Candidate gene-environment interaction studies have suggested interactions between cigarette smoking and NAT2/GSTM1 gene variants. Our objective was to perform a genome-wide association case-only study using the French national prospective COBLAnCE cohort (COhort to study BLAdder CancEr), focusing on smoking behavior. The COBLAnCE cohort comprises 1800 BC patients enrolled between 2012 and 2018. Peripheral blood samples collected at enrolment were genotyped using the Illumina Global Screening Array with a Multi-Disease drop-in panel. Genotyping data (9,719,614 single nucleotide polymorphisms (SNP)) of 1674, 1283, and 1342 patients were analyzed for smoking status, average tobacco consumption, and age at smoking initiation, respectively. A genome-wide association study (GWAS) was conducted adjusting for gender, age, and genetic principal components. The results suggest new candidate loci (4q22.1, 12p13.1, 16p13.3) interacting with smoking behavior for the risk of BC. Our results need to be validated in other case-control or cohort studies.

Germline HPF1 retrogene insertion in RB1 gene involved in cancer predisposition.

About half of the human genome is composed of repeated sequences derived from mobile elements, mainly retrotransposons, generally without pathogenic effect. Familial forms of retinoblastoma are caused by germline pathogenic variants in RB1 gene. Here, we describe a family with retinoblastoma affecting a father and his son. No pathogenic variant was identified after DNA analysis of RB1 gene coding sequence and exon-intron junctions. However, RB1 mRNA analysis showed a chimeric transcript with insertion of 114 nucleotides from HPF1 gene inside RB1 gene. This chimeric transcript led to an insertion of 38 amino acids in functional domain of retinoblastoma protein. Subsequent DNA analysis in RB1 intron 17 revealed the presence of a full-length HPF1 retrogene insertion in opposite orientation. Functional assay shows that this insertion has a deleterious impact on retinoblastoma protein function. This is the first report of a full-length retrogene insertion involved in human Mendelian disease leading to a chimeric transcript and a non-functional chimeric protein. Some retrogene insertions may be missed by standard diagnostic genetic testing, so contribution of retrogene insertions to human disease may be underestimated. The increasing use of whole genome sequencing in diagnostic settings will help to get a more comprehensive view of retrogenes.

Transcriptomic Profiling of Upper Tract Urothelial Carcinoma: Bladder Cancer Consensus Classification Relevance, Molecular Heterogeneity, and Differential Immune Signatures.

Analyses of large transcriptomics data sets of muscle-invasive bladder cancer (MIBC) have led to a consensus classification. Molecular subtypes of upper tract urothelial carcinomas (UTUCs) are less known. Our objective was to determine the relevance of the consensus classification in UTUCs by characterizing a novel cohort of surgically treated ≥pT1 tumors. Using immunohistochemistry (IHC), subtype markers GATA3-CK5/6-TUBB2B in multiplex, CK20, p16, Ki67, mismatch repair system proteins, and PD-L1 were evaluated. Heterogeneity was assessed morphologically and/or with subtype IHC. FGFR3 mutations were identified by pyrosequencing. We performed 3'RNA sequencing of each tumor, with multisampling in heterogeneous cases. Consensus classes, unsupervised groups, and microenvironment cell abundance were determined using gene expression. Most of the 66 patients were men (77.3%), with pT1 (n = 23, 34.8%) or pT2-4 stage UTUC (n = 43, 65.2%). FGFR3 mutations and mismatch repair-deficient status were identified in 40% and 4.7% of cases, respectively. Consensus subtypes robustly classified UTUCs and reflected intrinsic subgroups. All pT1 tumors were classified as luminal papillary (LumP). Combining our consensus classification results with those of previously published UTUC cohorts, LumP tumors represented 57.2% of ≥pT2 UTUCs, which was significantly higher than MIBCs. Ten patients (15.2%) harbored areas of distinct subtypes. Consensus classes were associated with FGFR3 mutations, stage, morphology, and IHC. The majority of LumP tumors were characterized by low immune infiltration and PD-L1 expression, in particular, if FGFR3 mutated. Our study shows that MIBC consensus classification robustly classified UTUCs and highlighted intratumoral molecular heterogeneity. The proportion of LumP was significantly higher in UTUCs than in MIBCs. Most LumP tumors showed low immune infiltration and PD-L1 expression and high proportion of FGFR3 mutations. These findings suggest differential response to novel therapies between patients with UTUC and those with MIBC.

Epigenomic mapping identifies an enhancer repertoire that regulates cell identity in bladder cancer through distinct transcription factor networks.

Muscle-invasive bladder cancer (BLCA) is an aggressive disease. Consensus BLCA transcriptomic subtypes have been proposed, with two major Luminal and Basal subgroups, presenting distinct molecular and clinical characteristics. However, how these distinct subtypes are regulated remains unclear. We hypothesized that epigenetic activation of distinct super-enhancers could drive the transcriptional programs of BLCA subtypes. Through integrated RNA-sequencing and epigenomic profiling of histone marks in primary tumours, cancer cell lines, and normal human urothelia, we established the first integrated epigenetic map of BLCA and demonstrated the link between subtype and epigenetic control. We identified the repertoire of activated super-enhancers and highlighted Basal, Luminal and Normal-associated SEs. We revealed super-enhancer-regulated networks of candidate master transcription factors for Luminal and Basal subgroups including FOXA1 and ZBED2, respectively. FOXA1 CRISPR-Cas9 mutation triggered a shift from Luminal to Basal phenotype, confirming its role in Luminal identity regulation and induced ZBED2 overexpression. In parallel, we showed that both FOXA1 and ZBED2 play concordant roles in preventing inflammatory response in cancer cells through STAT2 inhibition. Our study furthers the understanding of epigenetic regulation of muscle-invasive BLCA and identifies a co-regulated network of super-enhancers and associated transcription factors providing potential targets for the treatment of this aggressive disease.

Prognostic impact of variant histologies in urothelial bladder cancer treated with radical cystectomy.

OBJECTIVES: To evaluate variant histologies (VHs) for disease-specific survival (DSS) in patients with invasive urothelial bladder cancer (BCa) undergoing radical cystectomy (RC). MATERIALS AND METHODS: We analysed a multi-institutional cohort of 1082 patients treated with upfront RC for cT1-4aN0M0 urothelial BCa at eight centres. Univariable and multivariable Cox' regression analyses were used to assess the effect of different VHs on DSS in overall cohort and three stage-based analyses. The stages were defined as 'organ-confined' (≤pT2N0), 'locally advanced' (pT3-4N0) and 'node-positive' (pTanyN1-3). RESULTS: Overall, 784 patients (72.5%) had pure urothelial carcinoma (UC), while the remaining 298 (27.5%) harboured a VH. Squamous differentiation was the most common VH, observed in 166 patients (15.3%), followed by micropapillary (40 patients [3.7%]), sarcomatoid (29 patients [2.7%]), glandular (18 patients [1.7%]), lymphoepithelioma-like (14 patients [1.3%]), small-cell (13 patients [1.2%]), clear-cell (eight patients [0.7%]), nested (seven patients [0.6%]) and plasmacytoid VH (three patients [0.3%]). The median follow-up was 2.3 years. Overall, 534 (49.4%) disease-related deaths occurred. In uni- and multivariable analyses, plasmacytoid and small-cell VHs were associated with worse DSS in the overall cohort (both P = 0.04). In univariable analyses, sarcomatoid VH was significantly associated with worse DSS, while lymphoepithelioma-like VH had favourable DSS compared to pure UC. Clear-cell (P = 0.015) and small-cell (P = 0.011) VH were associated with worse DSS in the organ-confined and node-positive cohorts, respectively. CONCLUSIONS: More than 25% of patients harboured a VH at time of RC. Compared to pure UC, clear-cell, plasmacytoid, small-cell and sarcomatoid VHs were associated with worse DSS, while lymphoepithelioma-like VH was characterized by a DSS benefit. Accurate pathological diagnosis of VHs may ensure tailored counselling to identify patients who require more intensive management.

Progression-associated molecular changes in basal/squamous and sarcomatoid bladder carcinogenesis.

The aggressive basal/squamous (Ba/Sq) bladder cancer (BLCA) subtype is often diagnosed at the muscle-invasive stage and can progress to the sarcomatoid variant. Identification of molecular changes occurring during progression from non-muscle-invasive BLCA (NMIBC) to Ba/Sq muscle-invasive BLCA (MIBC) is thus challenging in human disease. We used the N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) mouse model of Ba/Sq MIBC to study longitudinally the molecular changes leading to the Ba/Sq phenotype and to the sarcomatoid variant using IHC and microdissection followed by RNA-seq at all stages of progression. A shift to the Ba/Sq phenotype started in early progression stages. Pathway analysis of gene clusters with coordinated expression changes revealed Shh signaling loss and a shift from fatty acid metabolism to glycolysis. An upregulated cluster, appearing early in carcinogenesis, showed relevance to human disease, identifying NMIBC patients at risk of progression. Similar to the human counterpart, sarcomatoid BBN tumors displayed a Ba/Sq phenotype and epithelial-mesenchymal transition (EMT) features. An EGFR/FGFR1 signaling switch occurred with sarcomatoid dedifferentiation and correlated with EMT. BLCA cell lines with high EMT were the most sensitive to FGFR1 knockout and resistant to EGFR knockout. Taken together, these findings provide insights into the underlying biology of Ba/Sq BLCA progression and sarcomatoid dedifferentiation with potential clinical implications. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Transcription factor EB regulates phosphatidylinositol-3-phosphate levels that control lysosome positioning in the bladder cancer model.

Lysosomes orchestrate degradation and recycling of exogenous and endogenous material thus controlling cellular homeostasis. Little is known how this organelle changes during cancer. Here we investigate the intracellular landscape of lysosomes in a cellular model of bladder cancer. Employing standardized cell culture on micropatterns we identify a phenotype of peripheral lysosome positioning prevailing in bladder cancer cell lines but not normal urothelium. We show that lysosome positioning is controlled by phosphatidylinositol-3-phosphate (PtdIns3P) levels on endomembranes which recruit FYVE-domain containing proteins for lysosomal dispersion. We identify transcription factor EB (TFEB) as an upstream regulator of PtdIns3P production by VPS34 that is activated in aggressive bladder cancer cells with peripheral lysosomes. This conceptually clarifies the dual role of TFEB as regulator of endosomal maturation and autophagy, two distinct processes controlled by PtdIns3P. Altogether, our findings uncover peripheral lysosome positioning, resulting from PtdIns3P production downstream of TFEB activation, as a potential biomarker for bladder cancer.

FGFR3 Mutational Activation Can Induce Luminal-like Papillary Bladder Tumor Formation and Favors a Male Sex Bias.

BACKGROUND: Bladder cancer (BCa) is more common in men and presents differences in molecular subtypes based on sex. Fibroblast growth factor receptor 3 (FGFR3) mutations are enriched in the luminal papillary muscle-invasive BCa (MIBC) and non-MIBC subtypes. OBJECTIVE: To determine whether FGFR3 mutations initiate BCa and impact BCa male sex bias. DESIGN, SETTING, AND PARTICIPANTS: We developed a transgenic mouse model expressing the most frequent FGFR3 mutation, FGFR3-S249C, in urothelial cells. Bladder tumorigenesis was monitored in transgenic mice, with and without carcinogen exposure. Mouse and human BCa transcriptomic data were compared. INTERVENTION: Mutant FGFR3 overexpression in mouse urothelium and siRNA knockdown in cell lines, and N-butyl-N(4-hydroxybutyl)-nitrosamine (BBN) exposure. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Impact of transgene dosage on tumor frequency, synergy with BBN treatment, and FGFR3 pathway activation were analyzed. The sex-specific incidence of FGFR3-mutated tumors was evaluated in mice and humans. FGFR3 expression in FGFR3-S249C mouse urothelium and in various human epithelia was measured. Mutant FGFR3 regulation of androgen (AR) and estrogen (ESR1) receptor activity was evaluated, through target gene expression (regulon) and reporter assays. RESULTS AND LIMITATIONS: FGFR3-S249C expression in mice induced low-grade papillary BCa resembling human luminal counterpart at histological, genomic, and transcriptomic levels, and promoted BBN-induced basal BCa formation. Mutant FGFR3 expression levels impacted tumor incidence in mice, and mutant FGFR3-driven human tumors were restricted to epithelia presenting high normal FGFR3 expression levels. BCa male sex bias, also found in our model, was even higher in human FGFR3-mutated tumors compared with wild-type tumors and was associated with higher AR and lower ESR1 regulon activity. Mutant FGFR3 expression inhibited both ESR1 and AR activity in mouse tumors and human cell lines, demonstrating causation only between FGFR3 activation and low ESR1 activity in tumors. CONCLUSIONS: Mutant FGFR3 initiates luminal papillary BCa formation and favors BCa male sex bias, potentially through FGFR3-dependent ESR1 downregulation. Patients with premalignant lesions or early-stage BCa could thus potentially benefit from FGFR3 targeting. FGFR3 expression level in epithelia could account for FGFR3-driven carcinoma tissue specificity. PATIENT SUMMARY: By developing a transgenic mouse model, we showed that gain-of-function mutations of FGFR3 receptor, among the most frequent genetic alterations in bladder cancer (BCa), initiate BCa formation. Our results could support noninvasive detection of FGFR3 mutations and FGFR3 targeting in early-stage bladder lesions.

Follow-up of intraocular retinoblastoma through the quantitative analysis of conserved nuclear DNA sequences in aqueous humor from patients.

Fundoscopy is the standard method for diagnosis and follow-up of intraocular retinoblastoma, but it is sometimes insufficient to discern whether tumors are inactivated following treatments. In this work, we hypothesized that the amount of conserved nuclear DNA sequences in the cell-free DNA (cfDNA) fraction of the aqueous humor (AH) might complement fundoscopy for retinoblastoma follow-up. To address our hypothesis, we developed highly sensitive droplet digital polymerase chain reaction (ddPCR) methods to quantify highly conserved DNA sequences of nucleus-encoded genes (GAPDH and B4GALNT1) and of a mitochondrial gene, MT-ATP6. We obtained AH samples during intravitreal treatments. We analyzed 42 AH samples from 25 patients with intraocular retinoblastoma and 11 AH from controls (non-cancer patients). According to clinical criteria, we grouped patients as having progression-free or progressive retinoblastoma. cfDNA concentration in the AH was similar in both retinoblastoma groups. Copy counts for nucleus-derived sequences of GAPDH and B4GALNT1 were significantly higher in the AH from patients with progressive disease, compared to the AH from progression-free patients and control non-cancer patients. The presence of mitochondrial DNA in the AH explained that both retinoblastoma groups had similar cfDNA concentration in AH. The optimal cut-off point for discriminating between progressive and progression-free retinoblastomas was 108 GAPDH copies per reaction. Among patients having serial AH samples analyzed during their intravitreal chemotherapy, GAPDH copies were high and decreased below the cut-off point in those patients responding to chemotherapy. In contrast, one non-responder patient remained with values above the cut-off during follow-up, until enucleation. We conclude that the measurement of conserved nuclear gene sequences in AH allows follow-up of intraocular retinoblastoma during intravitreal treatment. The method is applicable to all patients and could be relevant for those in which fundoscopy evaluation is inconclusive.

Tyro3 Targeting as a Radiosensitizing Strategy in Bladder Cancer through Cell Cycle Dysregulation.

Bladder cancer is a common cancer; it is the tenth most common cancer in the world. Around one fourth of all diagnosed patients have muscle-invasive bladder cancer (MIBC), characterized by advanced tumors and which remains a lethal disease. The standard treatment for MIBC is the bladder removal by surgery. However, bladder-preserving alternatives are emerging by combining chemotherapy, radiotherapy and minimal surgery, aiming to increase the patient's quality of life. The aim of the study was to improve these treatments by investigating a novel approach where in addition to radiotherapy, a receptor, TYRO3, a member of TAM receptor tyrosine kinase family known to be highly expressed on the bladder cancer cells and involved in the control of cell survival is targeted. For this, we evaluated the influence of TYRO3 expression levels on a colony or cell survival assays, DNA damage, γH2AX foci formation, gene expression profiling and cell cycle regulation, after radiation on different bladder cell models. We found that TYRO3 expression impacts the radiation response via the cell cycle dysregulation with noeffets on the DNA repair. Therefore, targeting TYRO3 is a promising sensitization marker that could be clinically employed in future treatments.

Integrated molecular and pharmacological characterization of patient-derived xenografts from bladder and ureteral cancers identifies new potential therapies.

Background: Muscle-invasive bladder cancer (MIBC) and upper urinary tract urothelial carcinoma (UTUC) are molecularly heterogeneous. Despite chemotherapies, immunotherapies, or anti-fibroblast growth factor receptor (FGFR) treatments, these tumors are still of a poor outcome. Our objective was to develop a bank of patient-derived xenografts (PDXs) recapitulating the molecular heterogeneity of MIBC and UTUC, to facilitate the preclinical identification of therapies. Methods: Fresh tumors were obtained from patients and subcutaneously engrafted into immune-compromised mice. Patient tumors and matched PDXs were compared regarding histopathology, transcriptomic (microarrays), and genomic profiles [targeted Next-Generation Sequencing (NGS)]. Several PDXs were treated with chemotherapy (cisplatin/gemcitabine) or targeted therapies [FGFR and epidermal growth factor (EGFR) inhibitors]. Results: A total of 31 PDXs were established from 1 non-MIBC, 25 MIBC, and 5 upper urinary tract tumors, including 28 urothelial (UC) and 3 squamous cell carcinomas (SCCs). Integrated genomic and transcriptomic profiling identified the PDXs of three different consensus molecular subtypes [basal/squamous (Ba/Sq), luminal papillary, and luminal unstable] and included FGFR3-mutated PDXs. High histological and genomic concordance was found between matched patient tumor/PDX. Discordance in molecular subtypes, such as a Ba/Sq patient tumor giving rise to a luminal papillary PDX, was observed (n=5) at molecular and histological levels. Ten models were treated with cisplatin-based chemotherapy, and we did not observe any association between subtypes and the response. Of the three Ba/Sq models treated with anti-EGFR therapy, two models were sensitive, and one model, of the sarcomatoid variant, was resistant. The treatment of three FGFR3-mutant PDXs with combined FGFR/EGFR inhibitors was more efficient than anti-FGFR3 treatment alone. Conclusions: We developed preclinical PDX models that recapitulate the molecular heterogeneity of MIBCs and UTUC, including actionable mutations, which will represent an essential tool in therapy development. The pharmacological characterization of the PDXs suggested that the upper urinary tract and MIBCs, not only UC but also SCC, with similar molecular characteristics could benefit from the same treatments including anti-FGFR for FGFR3-mutated tumors and anti-EGFR for basal ones and showed a benefit for combined FGFR/EGFR inhibition in FGFR3-mutant PDXs, compared to FGFR inhibition alone.

Identification of immunosuppressive factors in retinoblastoma cell secretomes and aqueous humor from patients.

The microenvironment of retinoblastoma, the solid malignancy of the developing retina, is immunosuppressive. To study the interactions between tumor-associated microglia/macrophages (TAMs) and tumor cells in retinoblastomas, we analyzed immunohistochemistry markers in 23 patient samples and characterized 105 secreted cytokines of 11 retinoblastoma cell models in culture. We detected profuse infiltration of CD163+ protumoral M2-like polarized TAMs in eyes enucleated due to cancer progression. Previous treatment of patients increased the number of TAMs but did not affect M2-like polarization. M2-like microglia/macrophages were almost absent in five eyes obtained from children enucleated due to nontumoral causes. CD8+ tumor-infiltrating lymphocytes (TILs) were moderately abundant in tumor eyes and very scarce in nontumoral ones. The expression of the immune checkpoint molecule PD-L1 was absent in 95% of the tumor samples, which is concordant with the finding of FOXP3+ Tregs infiltrating tumors. We confirmed the pathology results using single-cell transcriptome analysis of one tumor. We identified the cytokines extracellular matrix metalloproteinase inducer (EMMPRIN) and macrophage migration inhibitory factor (MIF), both with reported immunosuppressive activity, secreted at high levels in retinoblastoma primary cell cultures. Gene expression analysis of a large retinoblastoma cohort and single-cell transcriptome analysis confirmed that MIF and EMMPRIN were significantly upregulated in retinoblastomas, which led us to quantify both proteins by immunoassays in liquid biopsies (aqueous humor obtained from more than 20 retinoblastoma patients). We found a significant increase in the concentration of MIF and EMMPRIN in cancer patients, compared to 12 noncancer ones. Finally, we showed that macrophages derived from peripheral blood mononuclear cells increased the expression of markers of M2-like polarization upon exposure to retinoblastoma-conditioned medium or recombinant MIF. Overall, our findings suggest that retinoblastoma cell secretions induce the protumoral phenotype of this tumor. Our results might have clinical impact in the fields of biomarkers and treatment. © 2022 The Pathological Society of Great Britain and Ireland.

Multilayer spectrum of intratumoral heterogeneity in basal bladder cancer.

Basal/squamous (Ba/Sq) subtype represents an intrinsic and robust group in the consensus molecular classification of muscle-invasive bladder cancer (MIBC), with poor outcome and controversial chemosensitivity. We aimed to investigate the spectrum of intratumor heterogeneity (ITH) in the Ba/Sq subtype. First, we validated a 29-gene NanoString CodeSet to predict the Ba/Sq subtype for FFPE samples. We identified heterogeneous Ba/Sq tumors in a series of 331 MIBC FFPE samples using dual GATA3/KRT5/6 immunohistochemistry (IHC). Heterogeneous regions with distinct immunostaining patterns were studied separately for gene expression using the 29-gene CodeSet, for mutations by targeted next-generation sequencing, and for copy number alteration (CNA) by microarray hybridization. Among 83 Ba/Sq tumors identified by GATA3/KRT5/6 dual staining, 19 tumors showed heterogeneity at the IHC level. In one third of the 19 cases, regions from the same tumor were classified in different distinct molecular subtypes. The mutational and CNA profiles confirmed the same clonal origin for IHC heterogeneous regions with possible subclonal evolution. Overall, two patterns of intratumoral heterogeneity (ITH) were observed in Ba/Sq tumors: low ITH (regions with distinct immunostaining, but common molecular subtype and shared CNA) or high ITH (regions with distinct immunostaining, molecular subtype, and CNA). These results showed multilayer heterogeneity in Ba/Sq MIBC. In view of personalized medicine, this heterogeneity adds complexity and should be taken into account for sampling procedures used for diagnosis and treatment choice. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Prognostic markers in invasive bladder cancer: FGFR3 mutation status versus P53 and KI-67 expression: a multi-center, multi-laboratory analysis in 1058 radical cystectomy patients.

OBJECTIVES: To determine the association between the FGFR3 mutation status and immuno-histochemistry (IHC) markers (p53 and Ki-67) in invasive bladder cancer (BC), and to analyze their prognostic value in a multicenter, multi-laboratory radical cystectomy (RC) cohort. PATIENTS AND METHODS: We included 1058 cN0M0, chemotherapy-naive BC patients who underwent RC with pelvic lymph-node dissection at 8 hospitals. The specimens were reviewed by uro-pathologists. Mutations in the FGFR3 gene were examined using PCR-SNaPshot; p53 and Ki-67 expression were determined by standard IHC. FGFR3 mutation status as well as p53 (cut-off>10%) and Ki-67 (cut-off>20%) expression were correlated to clinicopathological parameters and disease specific survival (DSS). RESULTS: pT-stage was

Highly Sensitive Detection Method of Retinoblastoma Genetic Predisposition and Biomarkers.

Retinoblastoma is a malignant tumor of the infant retina. Nearly half of patients are predisposed to retinoblastoma by a germline RB1 pathogenic variant. Nonhereditary retinoblastoma is mainly caused by inactivation of both RB1 alleles at a somatic level. Several polymorphisms have been reported as biomarkers of retinoblastoma risk, aggressiveness, or invasion. The most informative genetic testing is obtained from tumor DNA. Historically, access to tumor DNA has been warranted by the frequent indication of enucleation, which has decreased because of advances in conservative approaches. Recent studies showed that tumor cell-free DNA can be analyzed in aqueous humor from retinoblastoma patients. This report describes a next-generation sequencing method relying on unique molecular identifiers for a highly sensitive detection of retinoblastoma genetic predisposition and biomarkers in a single analysis. It is the first use of unique molecular identifiers for retinoblastoma genetics. This gene panel enables the detection of RB1 point variants, large genome rearrangements, and loss of heterozygosity. It is adapted for genomic DNA extracted from blood or tumor DNA extracted from tumor fragment, aqueous humor, or plasma. The access to tumor cell-free DNA improves the diagnosis of genetic predisposition in case of conservative ocular therapy and provides access to biomarkers guiding the treatment strategy. The analysis of a gene panel is cost-effective and can be easily implemented in diagnostic laboratories.

STAG2 loss-of-function affects short-range genomic contacts and modulates the basal-luminal transcriptional program of bladder cancer cells.

Cohesin exists in two variants containing STAG1 or STAG2. STAG2 is one of the most mutated genes in cancer and a major bladder tumor suppressor. Little is known about how its inactivation contributes to tumorigenesis. Here, we analyze the genomic distribution of STAG1 and STAG2 and perform STAG2 loss-of-function experiments using RT112 bladder cancer cells; we then analyze the genomic effects by integrating gene expression and chromatin interaction data. Functional compartmentalization exists between the cohesin complexes: cohesin-STAG2 displays a distinctive genomic distribution and mediates short and mid-ranged interactions that engage genes at higher frequency than those established by cohesin-STAG1. STAG2 knockdown results in down-regulation of the luminal urothelial signature and up-regulation of the basal transcriptional program, mirroring differences between STAG2-high and STAG2-low human bladder tumors. This is accompanied by rewiring of DNA contacts within topological domains, while compartments and domain boundaries remain refractive. Contacts lost upon depletion of STAG2 are assortative, preferentially occur within silent chromatin domains, and are associated with de-repression of lineage-specifying genes. Our findings indicate that STAG2 participates in the DNA looping that keeps the basal transcriptional program silent and thus sustains the luminal program. This mechanism may contribute to the tumor suppressor function of STAG2 in the urothelium.