Heterogenous NECTIN4 expression in urothelial high-risk non-muscle-invasive bladder cancer.

High-grade non-muscle-invasive bladder cancer (HG NMIBC) patients are at high risk (HR) of progression to muscle-invasion. Bladder-preserving therapies for this patient subgroup are limited, and additional treatments are desirable. Recently, enfortumab vedotin, targeting cancer-associated NECTIN4, has been approved for the treatment of advanced urothelial carcinoma. However, data on the expression of NECTIN4 and its therapeutic potential for HR NMIBC are scarce. Here, NECTIN4 was immunohistochemically analyzed in urothelial HG NMIBC by studying cohorts of carcinoma in situ (CIS)/T1HG (N = 182 samples), HG papillary tumors from mixed-grade lesions (mixed TaHG) (N = 87) and papillary HG tumors without a history of low-grade disease (pure TaHG/T1HG) (N = 98) from overall 225 patients. Moreover, inter-lesional NECTIN4 heterogeneity in multifocal HG NMIBC tumors was determined. A high prevalence of NECTIN4 positivity was noted across HG NMIBC subgroups (91%, N = 367 samples), with 77% of samples showing moderate/strong expression. Heterogenous NECTIN4 levels were observed between HG NMIBC subgroups: non-invasive areas of CIS/T1HG and pure TaHG/T1HG samples showed NECTIN4 positivity in 96% and 99%, with 88% and 83% moderate/strong expressing specimens, respectively, whereas significantly lower NECTIN4 levels were detected in mixed TaHG lesions (72% positivity, 48% of samples with moderate/strong NECTIN4 expression). Moreover, higher NECTIN4 heterogeneity was observed in patients with multifocal mixed TaHG tumors (22% of patients) compared to patients with multifocal CIS/T1HG and pure TaHG/T1HG tumors (9% and 5%). Taken together, NECTIN4-directed antibody-drug conjugates might be promising for the treatment of HR NMIBC patients, especially for those exhibiting CIS/T1HG and pure TaHG/T1HG tumors without a history of low-grade disease.

Molecular Characterization of Muellerian Tumors of the Urinary Tract.

In the 2016 WHO classification of genitourinary tumors Muellerian tumors of the urinary tract (MTUT) comprise clear cell adenocarcinomas and endometrioid carcinomas. Since these rare tumors remained understudied, we aimed to characterize their molecular background by performing DNA- and RNA-based targeted panel sequencing. All tumors (n = 11) presented single nucleotide alterations (SNVs), with ARID1A mutations being the most prevalent (5/11, 45%). Besides frequent ARID1A mutations, loss of ARID1A protein is not a suitable marker since protein expression is (partly) preserved also in mutated cases. Copy number alterations (CNVs) were found in 64% of cases (7/11), exclusively gene amplifications. Interestingly, a functionally relevant RSPO2 gene fusion/microdeletion was discovered in the endometrioid adenocarcinoma case. Comparing our findings with mutational profiles of other tumor entities, absence of TERT promoter mutations argues for a non-urothelial origin. No similarities were also found between MTUT and kidney cancers while parallels were observed for specific SNVs with endometrial carcinomas. In conclusion, immunohistochemical PAX8-positivity and lack of TERT promoter mutations could serve as key diagnostic features in difficult cases. Thus, understanding the molecular background of these tumors helps to refine treatment options and offers the possibility of targeted therapies in cases where needed.

Intratumoral heterogeneity of surrogate molecular subtypes in urothelial carcinoma in situ of the urinary bladder: implications for prognostic stratification of high-risk non-muscle-invasive bladder cancer.

Reliable factors predicting the disease course of non-muscle-invasive bladder cancer (NMIBC) with carcinoma in situ (CIS) are unavailable. Molecular subtypes have potential for prognostic stratification of muscle-invasive bladder cancer, while their value for CIS patients is unknown. Here, the prognostic impact of both clinico-pathological parameters, including CIS focality, and immunohistochemistry-based surrogate subtypes was analyzed in a cohort of high-risk NMIBC patients with CIS. In 128 high-risk NMIBC patients with CIS, luminal (KRT20, GATA3, ERBB2) and basal (KRT5/6, KRT14) surrogate markers as well as p53 were analyzed in 213-231 biopsies. To study inter-lesional heterogeneity of CIS, marker expression in independent CIS biopsies from different bladder localizations was analyzed. Clinico-pathological parameters and surrogate subtypes were correlated with recurrence-free (RFS), progression-free (PFS), cancer-specific (CSS), and overall survival (OS). Forty-six and 30% of CIS patients exhibited a luminal-like (KRT20-positive, KRT5/6-negative) and a null phenotype (KRT20-negative, KRT5/6-negative), respectively. A basal-like subtype (KRT20-negative, KRT5/6-positive) was not observed. A significant degree of inter-lesional CIS heterogeneity was noted, reflected by 23% of patients showing a mixed subtype. Neither CIS surrogate subtype nor CIS focality was associated with patient outcome. Patient age and smoking status were the only potentially independent prognostic factors predicting RFS, PFS, OS, and PFS, respectively. In conclusion, further clarification of heterogeneity of surrogate subtypes in HR NMIBC and their prognostic value is of importance with regard to potential implementation of molecular subtyping into clinical routine. The potential prognostic usefulness of patient age and smoking status for high-risk NMIBC patients with CIS needs further validation.

SWI/SNF Alterations in Squamous Bladder Cancers.

Dysfunction of the SWI/SNF complex has been observed in various cancers including urothelial carcinomas. However, the clinical impact of the SWI/SNF complex in squamous-differentiated bladder cancers (sq-BLCA) remains unclear. Therefore, we aimed to analyze potential expression loss and genetic alterations of (putative) key components of the SWI/SNF complex considering the co-occurrence of genetic driver mutations and PD-L1 expression as indicators for therapeutic implications. Assessment of ARID1A, SMARCA2, SMARCA4, SMARCB1/INI1, SMARCC1, SMARCC2 and PBRM1 mutations in a TCGA data set of sq-BLCA (n = 45) revealed that ARID1A was the most frequently altered SWI/SNF gene (15%) while being associated with protein downregulation. Genetic alterations and loss of ARID1A were confirmed by Targeted Next Generation Sequencing (NGS) (3/6) and immunohistochemistry (6/116). Correlation with further mutational data and PD-L1 expression revealed co-occurrence of ARID1A loss and TP53 mutations, while positive correlations with other driver mutations such as PIK3CA were not observed. Finally, a rare number of sq-BLCA samples were characterized by both ARID1A protein loss and strong PD-L1 expression suggesting a putative benefit upon immune checkpoint inhibitor therapy. Hence, for the first time, our data revealed expression loss of SWI/SNF subunits in sq-BLCA, highlighting ARID1A as a putative target of a small subgroup of patients eligible for novel therapeutic strategies.

Pure high-grade papillary urothelial bladder cancer: a luminal-like subgroup with potential for targeted therapy.

PURPOSE: Non-invasive high-grade (HG) bladder cancer is a heterogeneous disease that is characterized insufficiently. First-line Bacillus Calmette-Guérin instillation fails in a substantial amount of cases and alternative bladder-preserving treatments are limited, underlining the need to promote a further molecular understanding of non-invasive HG lesions. Here, we characterized pure HG papillary urothelial bladder cancer (pure pTa HG), a potential subgroup of non-invasive HG bladder carcinomas, with regard to molecular subtype affiliation and potential for targeted therapy. METHODS: An immunohistochemistry panel comprising luminal (KRT20, ERBB2, ESR2, GATA3) and basal (KRT5/6, KRT14) markers as well as p53 and FGFR3 was used to analyze molecular subtype affiliations of 78 pure pTa HG/papillary pT1(a) HG samples. In 66 of these, ERBB2 fluorescence in situ hybridization was performed. Additionally, targeted sequencing (31 genes) of 19 pTa HG cases was conducted, focusing on known therapeutic targets or those described to predict response to targeted therapies noted in registered clinical trials or that are already approved. RESULTS: We found that pure pTa HG/papillary pT1(a) HG lesions were characterized by a luminal-like phenotype associated with frequent (58% of samples) moderate to high ERBB2 protein expression, rare FGFR3 alterations on genomic and protein levels, and a high frequency (89% of samples) of chromatin-modifying gene alterations. Of note, 95% of pTa HG/papillary pT1 HG cases harbored at least one potential druggable genomic alteration. CONCLUSIONS: Our data should help guiding the selection of targeted therapies for investigation in future clinical trials and, additionally, may provide a basis for prospective mechanistic studies of pTa HG pathogenesis.

Comparative genomic profiling of glandular bladder tumours.

Primary glandular bladder tumours (bladder adenocarcinoma [BAC], urachal adenocarcinoma [UAC], urothelial carcinoma with glandular differentiation [UCg]) are rare malignancies with histological resemblance to colorectal adenocarcinoma (CORAD) in the majority of this subgroup. Definite case numbers are very low, molecular data are limited and the pathogenesis remains poorly understood. Therefore, this study was designed to complement current knowledge by in depth analysis of BAC (n = 12), UAC (n = 13), UCg (n = 11) and non-invasive glandular lesions (n = 19). In BAC, in addition to known alterations in TP53, Wnt, MAP kinase and MTOR pathway, mutations in SMAD4, ARID1A and BRAF were identified. Compared to published data on muscle invasive bladder cancer (BLCA) and CORAD, UCg exhibited frequent "urothelial" like alterations while BAC and UAC were characterised by a more "colorectal" like mutational pattern. Immunohistochemically, there was no evidence of DNA mismatch repair deficiency or PD-L1 tumour cell positivity in any sample. Depending on the used antibody 0-45% of BAC, 0-30% of UCg and 0% UAC cases exhibited PD-L1 expressing tumour associated immune cells. A single BAC (9%, 1/11) showed evidence of ARID1A protein loss, and two cases of UCg (20%, 2/10) showed loss of SMARCA1 and PBRM1, respectively. Taken together, our data suggest at least in part involvement of similar pathways driving tumourigenesis of adenocarcinomas like BAC, UAC and CORAD independent of their tissue origin. Alterations of TERT and FBXW7 in single cases of intestinal metaplasia further point towards a possible precancerous character in line with previous reports.

Next-Generation Sequencing Reveals Potential Predictive Biomarkers and Targets of Therapy for Urothelial Carcinoma in Situ of the Urinary Bladder.

Bacillus Calmette-Guérin instillation after removal of the tumor is the first line of treatment for urothelial carcinoma in situ (CIS), the precursor lesion of most muscle-invasive bladder cancers. Bacillus Calmette-Guérin therapy fails in >50% of cases, and second-line radical cystectomy is associated with overtreatment and drastic lifestyle consequences. Given the need for alternative bladder-preserving therapies, we identified genomic alterations (GAs) in urothelial CIS having the potential to predict response to targeted therapies. Laser-capture microdissection was applied to isolate 30 samples (25 CIS and 5 muscle controls) from 26 fresh-frozen cystectomy specimens. Targeted next-generation sequencing of 31 genes was performed. The panel comprised genes frequently affected in muscle-invasive bladder cancer of nonpapillary origin, focusing on potentially actionable GAs described to predict response to approved targeted therapies or drugs that are in registered clinical trials. Of CIS patients, 92% harbored at least one potentially actionable GA, which was identified in TP53/cell cycle pathway-related genes (eg, TP53 and MDM2) in 72%, genes encoding chromatin-modifying proteins (eg, ARID1A and KDM6A) in 68%, DNA damage repair genes (eg, BRCA2 and ATM) in 60%, and phosphatidylinositol 3-kinase/mitogen-activated protein kinase pathway genes (eg, ERBB2 and FGFR1) in 36% of the cases. These data might help guide the selection of targeted therapies to be investigated in future clinical CIS trials, and they may provide a basis for future mechanistic studies of urothelial CIS pathogenesis.

ARID1A-deficiency in urothelial bladder cancer: No predictive biomarker for EZH2-inhibitor treatment response?

Bladder cancer therapy relies on aggressive treatments highlighting the need for new, targeted therapies with reduced side effects. SWI/SNF complexes are mutated in ~20% across human cancers and dependency of SWI/SNF-deficient tumors on EZH2 has been uncovered recently. To systematically dissect the frequency of genetic alterations in SWI/SNF complexes potentially contributing to their inactivation, mutations and copy number variations in 25 SWI/SNF subunit genes were analyzed making use of publicly available sequencing data for 408 muscle-invasive bladder carcinoma samples. ARID1A truncating mutations were identified as the by far most common alterations of SWI/SNF complexes in urothelial bladder cancer. As current ARID1A protein expression data in bladder cancer are inconsistent and incomplete we examined if the frequency of truncating ARID1A mutations translates into a similar frequency of cases showing ARID1A protein loss. We applied a validated ARID1A antibody conducting a comprehensive immunohistochemistry-based expression analysis in urothelial bladder cancer (n = 362) including carcinoma in situ (CIS) cases. While observing increased median ARID1A protein levels in all carcinoma subgroups compared to normal urothelial controls (n = 21), the percentage of cases showing ARID1A protein loss was positively correlated with increasing stage and grade culminating in a rate of 14.1% in muscle-invasive disease. ARID1A-depletion did neither increase EZH2 protein or trimethylated H3K27 levels in vitro nor did ARID1A expression correlate with EZH2 or H3K27me3 amounts in human bladder carcinomas. Importantly, ARID1A-deficiency was neither associated with enhanced sensitivity towards inhibition of EZH2 enzymatic activity nor depletion of EZH2 protein. In summary, ARID1A truncating mutations, potentially translating into ARID1A protein loss in a subset of high-grade bladder cancers, are the most common SWI/SNF genetic alterations in bladder cancer. Our data do not support ARID1A-deficiency as predictive biomarker for EZH2-inhibitor treatment response in bladder cancer underlining the need for future bladder cancer-specific, drug screens for successfull discovery of ARID1A-deficiency-based targeted drugs.

Progression of urothelial carcinoma in situ of the urinary bladder: a switch from luminal to basal phenotype and related therapeutic implications.

The stratification of bladder cancer into luminal and basal tumors has recently been introduced as a novel prognostic system in patient cohorts of muscle-invasive bladder cancer or high-grade papillary carcinomas. Using a representative immunohistochemistry panel, we analyzed luminal and basal marker expression in a large case series (n = 156) of urothelial carcinoma in situ (CIS), a precancerous lesion that frequently progresses to muscle-invasive disease. The majority of CIS cases was characterized by a positivity for luminal markers (aberrant cytokeratin (CK) 20 85% (132/156), GATA3 median Remmele score (score of staining intensity (0-3) multiplied with percentage of positive cells (0-4)): 12, estrogen receptor (ER) ß Remmele score > 2: 88% (138/156), human epidermal growth factor receptor 2 (Her2) Dako score 3+ 32% (50/156), Her2 Dako score 2+ 33% (51/156)), and marginal expression of basal markers (CK5/6+ 2% (3/156), CK14+ 1% (2/156)). To further investigate phenotypic stability during disease progression, we compared 48 pairs of CIS and invasive tumors from the same biopsy. A highly significant loss of luminal marker expression (p < 0.001) was observed in the course of progression whereas an increase of basal marker expression (p < 0.01) was noted in the invasive compartment. Importantly, 91% of CIS cases demonstrated a positivity for at least one of the two predictive markers Her2 and ERß, indicating that the analysis of Her2 and ERß may help to identify CIS-patient subgroups prone to more efficient targeted treatment strategies. Larger prospective and biomarker-embedded clinical trials are needed to confirm and validate our preliminary findings.

Oncogenic features of neuromedin U in breast cancer are associated with NMUR2 expression involving crosstalk with members of the WNT signaling pathway.

Neuromedin U (NMU) has been shown driving the progression of various tumor entities, including breast cancer. However, the expression pattern of NMU and its receptors in breast cancer tissues as well as systematic insight into mechanisms and downstream targets of the NMU-driven signaling pathways are still elusive. Here, NMU expression was found up-regulated in all breast cancer subtypes when compared to healthy breast tissue. Using an in silico dataset comprising 1,195 samples, high NMU expression was identified as an indicator of poor outcome in breast tumors showing strong NMUR2 expression. Next, the biological impact of NMU on breast cancer cells in relation to NMUR2 expression was analyzed. Ectopic NMU expression reduced colony growth while promoting a motile phenotype in NMUR2-positive SKBR3 but not NMUR2-negative Hs578T cells. To uncover signaling pathways and key molecules affected by NMU in SKBR3 cells, Affymetrix microarray analysis was applied. Forced NMU expression affected molecules involved in WNT receptor signaling among others. As such we demonstrated enhanced activation of the WNT/planar cell polarity (PCP) effector RAC1 and down-regulation of canonical WNT targets such as MYC. In summary, NMU might contribute to progression of NMUR2-positive breast cancer representing a potential druggable target for future personalized strategies.

Loss of Dickkopf 3 Promotes the Tumorigenesis of Basal Breast Cancer.

Dickkopf 3 (DKK3) has been associated with tumor suppression of various tumor entities including breast cancer. However, the functional impact of DKK3 on the tumorigenesis of distinct molecular breast cancer subtypes has not been considered so far. Therefore, we initiated a study analyzing the subtype-specific DKK3 expression pattern as well as its prognostic and functional impact with respect to breast cancer subtypes. Based on three independent tissue cohorts including one in silico dataset (n = 30, n = 463 and n = 791) we observed a clear down-regulation of DKK3 expression in breast cancer samples compared to healthy breast tissue controls on mRNA and protein level. Interestingly, most abundant reduction of DKK3 expression was detected in the highly aggressive basal breast cancer subtype. Analyzing a large in silico dataset comprising 3,554 cases showed that low DKK3 mRNA expression was significantly associated with reduced recurrence free survival (RFS) of luminal and basal-like breast cancer cases. Functionally, DKK3 re-expression in human breast cancer cell lines led to suppression of cell growth possibly mediated by up-regulation of apoptosis in basal-like but not in luminal-like breast cancer cell lines. Moreover, ectopic DKK3 expression in mesenchymal basal breast cancer cells resulted in partial restoration of epithelial cell morphology which was molecularly supported by higher expression of epithelial markers like E-Cadherin and down-regulation of mesenchymal markers such as Snail 1. Hence, we provide evidence that down-regulation of DKK3 especially promotes tumorigenesis of the aggressive basal breast cancer subtype. Further studies decoding the underlying molecular mechanisms of DKK3-mediated effects may help to identify novel targeted therapies for this clinically highly relevant breast cancer subtype.

AGR3 in breast cancer: prognostic impact and suitable serum-based biomarker for early cancer detection.

Blood-based early detection of breast cancer has recently gained novel momentum, as liquid biopsy diagnostics is a fast emerging field. In this study, we aimed to identify secreted proteins which are up-regulated both in tumour tissue and serum samples of breast cancer patients compared to normal tissue and sera. Based on two independent tissue cohorts (n = 75 and n = 229) and one serum cohort (n = 80) of human breast cancer and healthy serum samples, we characterised AGR3 as a novel potential biomarker both for breast cancer prognosis and early breast cancer detection from blood. AGR3 expression in breast tumours is significantly associated with oestrogen receptor α (P<0.001) and lower tumour grade (P<0.01). Interestingly, AGR3 protein expression correlates with unfavourable outcome in low (G1) and intermediate (G2) grade breast tumours (multivariate hazard ratio: 2.186, 95% CI: 1.008-4.740, P<0.05) indicating an independent prognostic impact. In sera analysed by ELISA technique, AGR3 protein concentration was significantly (P<0.001) elevated in samples from breast cancer patients (n = 40, mainly low stage tumours) compared to healthy controls (n = 40). To develop a suitable biomarker panel for early breast cancer detection, we measured AGR2 protein in human serum samples in parallel. The combined AGR3/AGR2 biomarker panel achieved a sensitivity of 64.5% and a specificity of 89.5% as shown by receiver operating characteristic (ROC) curve statistics. Thus our data clearly show the potential usability of AGR3 and AGR2 as biomarkers for blood-based early detection of human breast cancer.