Low frequency of defective mismatch repair in a population-based series of upper urothelial carcinoma

Inherited Germline Variants in Urinary Tract Cancer: A Multicenter Whole-Exome Sequencing Analysis and Correlation With Clinical Features and Tumor Genomics

PURPOSE

This study investigates a real-world multicenter cohort of patients with urinary tract cancer (UTC), with primary disease sites including the bladder, urethra, and upper tract, who enrolled for research molecular testing of their germline and tumor. The purpose of this study was to evaluate factors that could affect the likelihood of identifying a clinically actionable germline pathogenic variant (PV).

METHODS

Patients with UTC were identified from 10 cancer institutes of the Oncology Research Information Exchange Network consortium. The data set comprised abstracted clinical data with germline and tumor genomic data, and comparative analyses were conducted.

RESULTS

Clinically actionable germline PVs in cancer predisposition genes were identified in 16 (4.5%) of 354 patients. A higher proportion of patients with the urethra and the upper tract as the primary sites of disease had PVs with a prevalence of 11% (5/45), compared with only 3.6% (11/308) in those with the bladder as the primary site of disease (P = .04). There were no significant differences in markers of genomic instability (such as tumor mutational burden, microsatellite instability [MSI], and loss of heterozygosity, copy number, and chromosomal instability) between those with PVs and those without (P > .05). Of the PVs identified, 10 (62%) were in homologous recombination repair (HRR) genes, three (19%) in mismatch repair (MMR) genes, and three (19%) in genes associated with other pathways.

CONCLUSION

Tissue-based assessment of genomic instability, such as MSI, does not reliably indicate germline PV. A comprehensive clinical germline testing approach that includes HRR genes in addition to MMR genes is likely to yield PVs in approximately one of 10 patients with nonbladder primary disease sites such as the upper tract and the urethra.

A collaborative review of the microsatellite instability/deficient mismatch repair phenotype in patients with upper tract urothelial carcinoma

OBJECTIVE

To perform a collaborative review of the literature exploring the microsatellite instability/deficient mismatch repair (MSI/dMMR) phenotype in patients with upper tract urothelial carcinoma (UTUC).

METHOD

A collaborative review of the literature available on Medline was conducted by the Cancer Committee of the French Association of Urology to report studies describing the genetic mechanisms, investigation, prevalence and impact of the MSI/dMMR phenotype in UTUC patients.

RESULTS

The predominant genetic mechanism leading to the MSI/dMMR phenotype in UTUC patients is related to the constitutional mutation of one allele of the MMR genes MLH1, MSH2, MSH6 and PMS2 within Lynch syndrome. Indications for its investigation currently remain limited to patients with a clinical suspicion for sporadic UTUC to refer only those with a positive testing for germline DNA sequencing to screen for this syndrome. With regard to technical aspects, despite the interest of MSIsensor, only PCR and immunohistochemistry are routinely used to somatically investigate the MSI and dMMR phenotypes, respectively. The prevalence of the MSI/dMMR phenotype in UTUC patients ranges from 1.7% to 57%, depending on the study population, investigation method and definition of a positive test. Younger age and a more balanced male to female ratio at initial diagnosis are the main specific clinical characteristics of UTUC patients with an MSI/dMMR phenotype. Despite the conflicting results available in the literature, these patients may have a better prognosis, potentially related to more favourable pathological features. Finally, they may also have lower sensitivity to chemotherapy but greater sensitivity to immunotherapy.

CONCLUSION

Our collaborative review summarises the available data from published studies exploring the MSI/dMMR phenotype in UTUC patients, the majority of which are limited by a low level of evidence.

Mismatch repair deficiency and microsatellite instability in urothelial carcinoma: a systematic review and meta-analysis

Background

Mismatch repair deficiency (dMMR) and microsatellite instability-high (MSI-H) occur in a subset of cancers and have been shown to confer sensitivity to immune checkpoint inhibition (ICI); however, there is a lack of prospective data in urothelial carcinoma (UC).

Methods and analysis

We performed a systematic review to estimate the prevalence of dMMR and MSI-H in UC, including survival and clinical outcomes. We searched for studies published up to 26 October 2022 in major scientific databases. We screened 1745 studies and included 110. Meta-analyses were performed if the extracted data were suitable.

Results

The pooled weighted prevalences of dMMR in bladder cancer (BC) and upper tract UC (UTUC) were 2.30% (95% CI 1.12% to 4.65%) and 8.95% (95% CI 6.81% to 11.67%), respectively. The pooled weighted prevalences of MSI-H in BC and UTUC were 2.11% (95% CI 0.82% to 5.31%) and 8.36% (95% CI 5.50% to 12.53%), respectively. Comparing localised versus metastatic disease, the pooled weighted prevalences for MSI-H in BC were 5.26% (95% CI 0.86% to 26.12%) and 0.86% (95% CI 0.59% to 1.25%), respectively; and in UTUC, they were 18.04% (95% CI 13.36% to 23.91%) and 4.96% (95% CI 2.72% to 8.86%), respectively. Cumulatively, the response rate in dMMR/MSI-H metastatic UC treated with an ICI was 22/34 (64.7%) compared with 1/9 (11.1%) with chemotherapy.

Conclusion

Both dMMR and MSI-H occur more frequently in UTUC than in BC. In UC, MSI-H occurs more frequently in localised disease than in metastatic disease. These biomarkers may predict sensitivity to ICI in metastatic UC and resistance to cisplatin-based chemotherapy.

Frequency of microsatellite instability (MSI) in upper tract urothelial carcinoma: comparison of the Bethesda panel and the Idylla MSI assay in a consecutively collected, multi-institutional cohort

AIMS

Upper tract urothelial carcinoma (UTUC) is a rare malignancy with a poor prognosis which occurs sporadically or in few cases results from a genetic disorder called Lynch syndrome. Recently, examination of microsatellite instability (MSI) has gained importance as a biomarker: MSI tumours are associated with a better response to immunomodulative therapies. Limited data are known about the prevalence of MSI in UTUC. New detection methods using the fully automated Idylla MSI Assay facilitate analysis of increased patient numbers.

METHODS

We investigated the frequency of MSI in a multi-institutional cohort of 243 consecutively collected UTUC samples using standard methodology (Bethesda panel), along with immunohistochemistry of mismatch repair (MMR) proteins. The same tumour cohort was retested using the Idylla MSI Assay by Biocartis.

RESULTS

Using standard methodology, 230/243 tumours were detected as microsatellite stable (MSS), 4/243 tumours as MSI and 9/243 samples as invalid. In comparison, the Idylla MSI Assay identified four additional tumours as MSS, equalling 234/243 tumours; 4/243 were classified as MSI and only 5/243 cases as invalid. At the immunohistochemical level, MSI results were supported in all available cases with a loss in MMR proteins. The overall concordance between the standard and the Idylla MSI Assay was 98.35%. Time to result differed between 3 hours for Idylla MSI Assay and 2 days with the standard methodology.

CONCLUSION

Our data indicate a low incidence rate of MSI tumours in patients with UTUC. Furthermore, our findings highlight that Idylla MSI Assay can be applied as an alternative method of MSI analysis for UTUC.

[Immunological biomarker research in uro-oncology-using the example of urothelial cancer]

The most common malignant tumor of the urinary tract system is urothelial carcinoma (UC). With the introduction of novel immunologic therapy options in both metastatic and localized settings, the exploration of immunologic biomarkers to predict potential treatment success has become a focus of clinical translational research. For example, expression levels of programmed cell death ligand 1 (PD-L1) in UC tumors can help clinicians decide which patients are more likely to respond to immuno-oncology therapies; in light of new approvals with mandated PD-L1 testing (e.g., adjuvant nivolumab therapy after radical cystectomy), harmonization of PD-L1 testing is becoming increasingly important. However, in addition to PD-L1 determination, broader potentially predictive biomarkers such as tumor mutational burden and immune signatures/phenotypes have been and continue to be investigated in clinical trials. This review will provide a streamlined overview of existing evidence and new developments in the field of urothelial carcinoma.

Mismatch repair proteins play a role in ATR activation upon temozolomide treatment in MGMT-methylated glioblastoma

The methylation status of the O⁶-methylguanine methyltransferase (MGMT) gene promoter has been widely accepted as a prognostic biomarker for treatment with the alkylator, temozolomide (TMZ). In the absence of promoter methylation, the MGMT enzyme removes O⁶-methylguanine (O⁶-meG) lesions. In the setting of MGMT-promoter methylation (MGMT-), the O⁶-meG lesion activates the mismatch repair (MMR) pathway which functions to remove the damage. Our group reported that loss of MGMT expression via MGMT promoter silencing modulates activation of ataxia telangiectasia and RAD3 related protein (ATR) in response to TMZ treatment, which is associated with synergistic tumor-cell killing. Whether or not MMR proteins are involved in ATR activation in MGMT-cells upon alkylation damage remains poorly understood. To investigate the function of MMR in ATR activation, we created isogenic cell lines with knockdowns of the individual human MMR proteins MutS homolog 2 (MSH2), MutS homolog 6 (MSH6), MutS homolog 3 (MSH3), MutL homolog 1 (MLH1), and PMS1 homolog 2 (PMS2). Here, we demonstrate that MSH2, MSH6, MLH1 and PMS2, specifically, are involved in the activation of the ATR axis after TMZ exposure, whereas MSH3 is likely not. This study elucidates a potential mechanistic understanding of how the MMR system is involved in ATR activation by TMZ in glioblastoma cells, which is important for targeting MMR-mutated cancers.

Immunohistochemical screening of upper tract urothelial carcinomas for Lynch syndrome diagnostics: a systematic review

OBJECTIVE

To review the effect of universal screening of newly diagnosed upper tract urothelial carcinomas (UTUC) for mismatch repair (MMR) protein loss to aid in Lynch syndrome diagnostics.

MATERIALS AND METHODS

Studies were identified through PubMed on December 1^st, 2021. Eligibility criteria were universal immunohistochemical analyses for at least two MMR proteins in unselected, consecutively collected UTUC cohorts. Exclusion criteria included reviews, case-reports, non-English language, and non-humans. Risk of bias was assessed using a modified Newcastle-Ottawa scale. Meta-analyses were performed to compare the association between clinical criteria and Lynch syndrome diagnoses.

RESULTS

From 12 included studies, 1628 surgically removed UTUC from 1626 patients were screened for MMR protein loss. In 11 studies, 140 of the 1559 patients had tumors with loss (9.0%) with 80.7% showing loss of MSH2, MSH6, or both. In 7 studies, genetic testing confirmed Lynch syndrome diagnosis for 20 of 970 patients (2.1%). In 8 studies, 31 patients were given a clinical Lynch syndrome diagnosis (2.6%). In total, 51 assumed or verified Lynch syndrome patients were identified among 1087 patients (4.7%). Meta-analyses of 3 studies showed significant association between previous cancer diagnosis and Lynch syndrome-associated UTUC (p = 0.038).

CONCLUSION

Despite the few studies conducted and lack of genetic testing, current data suggests that universal screening for MMR protein loss in UTUC may result in Lynch syndrome diagnoses in 4.7%. However, for the screening to be effective for Lynch syndrome diagnostics, follow-up investigations such as genetic testing for MMR variants are needed.

Nectin-4 and DNA mismatch repair proteins expression in upper urinary tract urothelial carcinoma (UTUC) as a model for tumor targeting approaches: an ImGO pilot study

BACKGROUND

Upper urinary tract urothelial carcinoma (UTUC) accounts for only about 5-10% of all urothelial cancers and is characterized by an aggressive and frequently rapidly fatal behavior. However, detailed knowledge of its molecular profile is still lacking.

MATERIALS AND METHODS

We identified, by chart analysis, patients who underwent radical nephroureterectomy or diagnostic biopsy for UTUC between January 2015 and August 2020 at the Santa Maria Hospital of Terni, in Italy. Eligible patients were required to have also adequate clinical informations and follow-up details. The primary objective of the study was to evaluate DNA mismatch repair (MMR) proteins and Nectin-4 immunohistochemical expression in UTUC, looking also for an eventual correlation between these molecular features. The secondary objective was to investigate genomic instability in the case of a MMR protein loss. Expression of proteins was assessed by using immunohistochemistry and microsatellite instability (MSI) performed by next generation sequencing. Nectin-4 expression was reported using an intensity scoring system (score, 0-3+), instead the expression of DNA MMR proteins was indicated as present (no loss) or not present (loss).

RESULTS

Thirty four cases have been evaluated and 27 considered eligible for the study with their tumor samples analyzed. Nectin-4 was found to be expressed in 44% of cases and 18.5% of patients showed defective-MMR phenotype. We found a significant correlation between Nectin-4 expression and MSH2/MSH6 protein loss. Out of 7 patients with DNA MMR proteins loss or equivocal phenotype, 3 showed MSI.

CONCLUSIONS

Our pilot study suggest a possible relationship between Nectin-4 and DNA MMR protein expression in UTUC and a clinically significant correlation between defective MMR phenotype and genomic instability. Because of the possible implications of these data for innovative treatment approaches, the need for further studies in this area is warranted.

Upper Tract Urothelial Carcinoma in the Lynch Syndrome Tumour Spectrum: A Comprehensive Overview from the European Association of Urology - Young Academic Urologists and the Global Society of Rare Genitourinary Tumors

CONTEXT

Upper tract urothelial carcinoma (UTUC) represents the third most frequent malignancy in Lynch syndrome (LS).

OBJECTIVE

To systematically review the available literature focused on incidence, diagnosis, clinicopathological features, oncological outcomes, and screening protocols for UTUC among LS patients.

EVIDENCE ACQUISITION

Medline, Scopus, Google Scholar, and Cochrane Database of Systematic Reviews were searched up to May 2021. Risk of bias was determined using the modified Cochrane tool. A narrative synthesis was undertaken.

EVIDENCE SYNTHESIS

Overall, 43 studies between 1996 and 2020 were included. LS patients exhibited a 14-fold increased risk of UTUC compared with the general population, which further increased to 75-fold among hMSH2 mutation carriers. Patients younger than 65 yr and patients with personal or family history of LS-related cancers should be referred to molecular testing on tumour specimen and subsequent genetic testing to confirm LS. Newly diagnosed LS patients may benefit from a multidisciplinary management team including gastroenterologist and gynaecologist specialists, while genetic counselling should be recommended to first-degree relatives (FDRs). Compared with sporadic UTUC individuals, LS patients were significantly younger (p = 0.005) and exhibited a prevalent ureteral location (p = 0.01). Radical nephroureterectomy was performed in 75% of patients (5-yr cancer-specific survival: 91%). No consensus on screening protocols for UTUC was achieved: starting age varied between 25-35 and 50 yr, while urinary cytology showed sensitivity of 29% and was not recommended for screening.

CONCLUSIONS

Urologists should recognise patients at high risk for LS and address them to a comprehensive diagnostic pathway, including molecular and genetic testing. Newly diagnosed LS patients should be referred to a multidisciplinary team, while genetic counselling should be recommended to FDRs.

PATIENT SUMMARY

In this systematic review, we analysed the existing literature focused on upper tract urothelial carcinoma (UTUC) among patients with Lynch syndrome (LS). Our purpose is to provide a comprehensive overview of LS-related UTUC to reduce misdiagnosis and improve patient prognosis.

Adjuvant pembrolizumab in genomically selected high-risk patients with muscle-invasive bladder cancer

INTRODUCTION

Patients with muscle-invasive urothelial bladder cancer post neoadjuvant cisplatin-based chemotherapy with pathologic advanced disease (ypT3, ypT4, ypN+) at radical cystectomy have a significantly worse five-year overall survival. There is currently no preferred adjuvant therapy to reduce risk of cancer recurrence in this high-risk patient cohort and surveillance remains the standard-of-care.

CASE REPORT

We present a case series of two patients who received cisplatin-based neoadjuvant chemotherapy and had pathologic node-positive urothelial carcinoma at the time of radical cystectomy. Tumor next generation sequencing revealed high mutational burden in both patients and positive PD-L1 in one patient.Management and outcome: Patients were treated with adjuvant pembrolizumab and experienced long-term disease free intervals.

DISCUSSION

Use of adjuvant checkpoint inhibitors in patients post neoadjuvant cisplatin-based chemotherapy with pathologic advanced disease at the time of radical cystectomy at high-risk of cancer recurrence sounds appealing. Careful patient selection based on tumor-specific genomic alterations may be key. Large trials addressing this question are ongoing.

Novel Tyrosine Kinase Targets in Urothelial Carcinoma

Urothelial carcinoma represents one of the most prevalent types of cancer worldwide, and its incidence is expected to grow. Although the treatment of the advanced disease was based on chemotherapy for decades, the developments of different therapies, such as immune checkpoint inhibitors, antibody drug conjugates and tyrosine kinase inhibitors, are revolutionizing the therapeutic landscape of this tumor. This development coincides with the increasing knowledge of the pathogenesis and genetic alterations in urothelial carcinoma, from the non-muscle invasive setting to the metastatic one. The purpose of this article is to provide a comprehensive review of the different tyrosine kinase targets and their roles in the therapeutic scene of urothelial carcinoma.

The Differential Diagnosis of Medullary-Based Renal Masses

CONTEXT.—

Renal malignancies can be divided into cortical- and medullary-based tumors, the latter of which classically infiltrate the renal parenchyma by extending between nonneoplastic structures. Although high-grade cortical tumors can rarely exhibit the same growth pattern, the infiltrative morphology should elicit a differential diagnosis to be considered in each case. However, these diagnoses can be challenging to distinguish, especially on small renal biopsy samples.

OBJECTIVE.—

To provide an overview of the clinical, gross, and microscopic findings; genetic and molecular alterations; and immunohistochemical evaluation of medullary-based renal tumors and other tumor types with overlapping morphologies and growth patterns.

DATA SOURCES.—

Literature review and personal observations were used to compile the information in this review.

CONCLUSIONS.—

Collecting duct carcinoma is a prototypical medullary-based tumor, and although diagnostic criteria exist, it remains a diagnosis of exclusion, especially with ancillary techniques aiding the recognition of established as well as more recently described neoplasms. Other medullary-based malignancies included in the differential diagnosis include renal medullary carcinoma/renal cell carcinoma unclassified with medullary phenotype, fumarate hydratase-deficient renal cell carcinoma, and upper tract urothelial carcinoma. Moreover, other rare entities should be excluded, including metastatic carcinoma, lymphoma, and melanoma. In addition to potential prognostic differences, accurate diagnoses can have important surgical and clinical management implications.

Universal Mismatch Repair Protein Screening in Upper Tract Urothelial Carcinoma

OBJECTIVES

Universal screening of upper tract urothelial carcinoma (UTUC) for Lynch syndrome by mismatch repair (MMR) protein immunohistochemistry (IHC) has been recommended by some investigators. Herein, we assess this recommendation retrospectively by simulating its performance on a retrospective, unselected cohort of UTUCs, with comparison to the established setting of colorectal and endometrial adenocarcinoma.

METHODS

We assessed for complete loss of MMR protein (MLH1, MSH2, MSH6, and PMS2) IHC in 74 consecutive cases of UTUC and then tabulated clinical and pathologic factors. MMR findings from same-institution colorectal and endometrial adenocarcinomas were tabulated for comparison.

RESULTS

We observed loss of at least one MMR protein in 12% in our UTUC cohort (three MSH2/MSH6, three MSH6 only, one MLH1/PMS2, and two PMS2 only). Of these nine cases (seven males, two females, median age 67 years, five associated with colorectal adenocarcinoma), at least three (4% of the overall cohort) proved to be Lynch syndrome. Overall, MMR loss in UTUC was comparable to colorectal (11%; 50 of 471 cases) and endometrial (12%; 12 of 101 cases) adenocarcinomas.

CONCLUSIONS

The rate of MMR loss observed in UTUC was comparable to that in the established setting of colorectal and endometrial adenocarcinomas, supporting universal UTUC screening at our institution and others.

Management of Urothelial Bladder Cancer in Clinical Practice: Real-World Answers to Difficult Questions

Management of urothelial bladder cancer has historically been challenging as a result of a limited grasp of disease biology and few available systemic therapy options, mainly consisting of platinum-based chemotherapy. Improved understanding of molecular mechanisms underlying pathogenesis of muscle-invasive bladder cancer as well as their correlation with tumor behavior and response to treatment has emerged over the past few years. Remarkable therapeutic advances have been made with the introduction of checkpoint inhibitors, which have changed the course of this disease. Multiple agents with novel mechanisms of action are also actively being explored in ongoing clinical trials. These advances are exciting but may prove challenging in terms of how to apply this constantly evolving plethora of data to actual patients. This review addresses the gray areas and challenging questions that frequently arise in clinical practice.

Molecular Characterization of Upper Tract Urothelial Carcinoma in the Era of Next-generation Sequencing: A Systematic Review of the Current Literature

CONTEXT

While upper tract urothelial carcinoma (UTUC) share histological appearance with bladder cancer (BC), the former has differences in etiology and clinical phenotype consistent with characteristic molecular alterations.

OBJECTIVE

To systematically evaluate current genomic sequencing and proteomic data examining molecular alterations in UTUC.

EVIDENCE ACQUISITION

A systematic review using PubMed, Scopus, and Web of Science was performed in December 2019 according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement.

EVIDENCE SYNTHESIS

A total of 46 publications were selected for inclusion in this report, including 13 studies assessing genome-wide alterations, 18 studies assessing gene expression or microRNA expression profiles, three studies assessing proteomics, one study assessing genome-wide DNA methylation, and 14 studies evaluating distinct pathway alteration patterns. Differences between sporadic and hereditary UTUC, and between UTUC and BC, as well as molecular profiles associated with exposure to aristolochic acid are highlighted. Molecular pathways relevant to UTUC biology, such as alterations in FGFR3, TP53, or microsatellite instability, are discussed. Our findings are limited by tumor and patient heterogeneity and different platforms used in the studies.

CONCLUSIONS

Molecular events in UTUC and BC can be shared or distinct. Consequently, molecular subtypes differ according to location. Further work is needed to define the epigenomic and proteomic features of UTUC, and understand the mechanisms by which they shape the clinical behavior of UTUC.

PATIENT SUMMARY

We report the current data on the molecular alterations specific to upper tract urothelial carcinoma (UTUC), resulting from novel genomic and proteomic technologies. Although UTUC biology is comparable with that of bladder cancer, the rates and UTUC-enriched alterations support its uniqueness and the need for precision medicine strategies for this rare tumor type.

Prevalence of Lynch syndrome among patients with upper urinary tract carcinoma in a Japanese hospital-based population

BACKGROUND

The prevalence of Lynch syndrome and the use of universal tumor screening to identify Lynch syndrome among unselected patients with upper urinary tract urothelial carcinoma, which is associated with Lynch syndrome, have not been closely investigated yet.

METHODS

A total of 166 tumors from 164 upper urinary tract urothelial carcinoma patients were tested for microsatellite instability and expression of mismatch repair proteins (MLH1, MHS2, MSH6 and PMS2) by immunohistochemistry. Genetic testing was performed for patients suspected of having Lynch syndrome. Clinicopathological factors, including familial and personal cancer history associated with mismatch repair deficiency, were evaluated.

RESULTS

The frequency of high-level microsatellite instability and loss of at least one mismatch repair protein was 2.4% (4/164); the microsatellite instability and immunohistochemistry results showed complete concordance. Of these four patients, three were genetically proven to have Lynch syndrome, while the remaining one was highly suggestive for Lynch syndrome based on their personal cancer history. Univariate analysis showed that age<70 years (P = 0.04), ureter as the tumor location (P = 0.052), previous history/synchronous diagnosis of colorectal cancer (P < 0.01) and fulfillment of the criteria per the revised Bethesda guideline (P < 0.01) tended to be or were significantly associated with high-level microsatellite instability/mismatch repair loss.

CONCLUSIONS

The prevalence of Lynch syndrome among unselected upper urinary tract urothelial carcinoma patients was at least 1.8% in our study population. The screening efficacies of the microsatellite instability test and immunohistochemistry appear equivalent. Universal tumor screening may be a valid approach; however, selective screening methods that consider factors associated with mismatch repair loss/high-level microsatellite instability tumors require further investigation.

Loss of Mismatch-repair Protein Expression and Microsatellite Instability in Upper Tract Urothelial Carcinoma and Clinicopathologic Implications

BACKGROUND

Upper tract urothelial carcinoma (UTUC) may arise in the setting of hereditary non-polyposis colorectal cancer (Lynch syndrome [LS]) or sporadically. Variable frequencies of microsatellite instability (MSI) were found in UTUC. For advanced solid MSI tumors, targeted therapy with programmed death-ligand 1 inhibitors is available. Therefore, we aimed to determine the prevalence of mismatch repair (MMR) protein loss and MSI in UTUC using a tissue microarray approach and further molecular and correlation analysis.

MATERIALS AND METHODS

We studied the immunohistochemical expression of MLH1, MSH2, MSH6, and PMS2 on tissue microarrays containing formalin-fixed, paraffin-embedded samples of 128 patients with UTUC. MSI analysis was performed in 79 cases with deficient MMR protein expression, and/or in patients aged 60 years and below, and/or other tumors possibly related to LS.

RESULTS

Loss of MMR protein expression was seen in 24 (18.8%) of 128 cases. MSI analysis revealed MSI-high in 29, MSI-low in 7 cases. The Fisher exact test demonstrated significant differences between MSI and loss of MMR protein expression, clinically possible LS, tumor growth pattern, inverted growth pattern, and death (P < .001, P < .001, P = .002, P = .003, and P = .033, respectively). MSI does not appear to influence survival (overall and progression-free), but there was a significant shorter progression-free survival in MSI-high versus MSS patients who had received chemotherapy.

CONCLUSION

The frequency of MSI in UTUC was 36 (28.1%) of 128 patients with a good accuracy of immunohistochemistry. In daily practice, MSI screening especially is recommended in patients with advanced UTUC and inverted papillary tumor growth pattern with the aim of screening patients for possible targeted therapy.

Inherited forms of bladder cancer: a review of Lynch syndrome and other inherited conditions

Environmental factors that play a role in the urothelial carcinogenesis have been well characterized. Current research is continuously exploring potential heritable forms of bladder cancer. Lynch syndrome is a well-known inheritable disease that increases the risk for a variety of cancers, including urothelial carcinomas. Screening of patients with known Lynch syndrome is important to evaluate for development of new primary tumors. Further study may provide more information on what level of follow-up each patient needs. Recent data suggest that mismatch repair mutations confer a greater risk for urothelial cancer. Additional large patient series as well as advancement of molecular testing may provide triage for Lynch syndrome patients in regards to the frequency and type of screening best suited for individual patient.

Biomarkers of immunotherapy in urothelial and renal cell carcinoma: PD-L1, tumor mutational burden, and beyond

Immune checkpoint inhibitors targeting the PD-1 pathway have greatly changed clinical management of metastatic urothelial carcinoma and metastatic renal cell carcinoma. However, response rates are low, and biomarkers are needed to predict for treatment response. Immunohistochemical quantification of PD-L1 was developed as a promising biomarker in early clinical trials, but many shortcomings of the four different assays (different antibodies, disparate cellular populations, and different thresholds of positivity) have limited its clinical utility. Further limitations include the use of archival specimens to measure this dynamic biomarker. Indeed, until PD-L1 testing is standardized and can consistently predict treatment outcome, the currently available PD-L1 assays are not clinically useful in urothelial and renal cell carcinoma. Other more promising biomarkers include tumor mutational burden, profiles of tumor infiltrating lymphocytes, molecular subtypes, and PD-L2. Potentially, a composite biomarker may be best but will need prospective testing to validate such a biomarker.

Upper tract urothelial carcinomas: frequency of association with mismatch repair protein loss and lynch syndrome

Increased risk for upper tract urothelial carcinoma is described in patients with Lynch syndrome, caused by germline mutations in mismatch repair genes. We aimed to identify the frequency of mismatch repair protein loss in upper tract urothelial carcinoma and its potential for identifying an association with Lynch syndrome. We queried our database to identify upper tract urothelial carcinomas. Patients were cross-referenced for history of colorectal carcinoma or other common Lynch syndrome-associated neoplasms to enrich for potential Lynch syndrome cases. Tumor histopathologic characteristics were reviewed and each case was analyzed for loss of mismatch repair proteins, MLH1, MSH2, MSH6, and PMS2, by immunohistochemistry. Of 444 patients with upper tract urothelial carcinoma, a subset of 215 (encompassing 30 with upper tract urothelial carcinoma and another common Lynch syndrome-associated neoplasm) was analyzed for loss of mismatch repair protein expression. Of 30 patients with Lynch syndrome-associated neoplasms, six had documented Lynch syndrome, including two with Muir-Torre syndrome. Mismatch repair protein loss was identified in 7% of total upper tract urothelial carcinomas and 30% of patients with Lynch syndrome-associated neoplasms (including all patients with Lynch syndrome/Muir-Torre syndrome). Of patients without history of Lynch syndrome-associated neoplasms, 5 of 184 (2.7%) had loss of mismatch repair protein expression. Twelve cases with mismatch repair protein loss demonstrated loss of MSH2 and MSH6, and 2 had isolated loss of MSH6. MLH1 and PMS2 expression were consistently retained. Although increased intratumoral lymphocytes, inverted growth, pushing tumor-stromal interface, and lack of nuclear pleomorphism were more commonly seen in cases with mismatch repair protein loss, only intratumoral lymphocytes and presence of pushing borders were statistically significant. MLH1 and PMS2 testing appear to have little utility in upper tract urothelial carcinoma; however, mismatch repair protein loss of MSH2 and/or MSH6 by immunohistochemistry seems relatively sensitive and specific for identifying patients with potential Lynch syndrome.

The Genetics of Colorectal Cancer

The hereditary colorectal cancer syndromes comprise a heterogeneous group of conditions with varying cancer risks, gastrointestinal polyp types, nonmalignant findings, and inheritance patterns. Although each one is unique in its own right, these syndromes often have overlapping features, making diagnoses difficult in select cases. Obtaining accurate polyp history (histologic type, number, location, and age of onset), cancer history (location, type, and age of onset), and other nonmalignant features is imperative in determining the likely disease diagnosis and thereby the appropriate genetic tests for precise diagnosis in a timely fashion. This process often necessitates collaboration among surgical oncology team members and genetic counselors.

Microsatellite instability and TARBP2 mutation study in upper urinary tract urothelial carcinoma

Microsatellite instability (MSI) contributes to the tumorigenesis of upper urinary tract urothelial carcinomas (UUT-UCs). In this study, we first used MLH1 and MSH2 immunohistochemistry to identify patients with loss of expression of either or both of these proteins in 132 UUT-UCs. We found a total loss of MSH2 expression in 4 patients. MSI was evaluated using 5 markers in these 4 cases. All of the tumors had high MSI (MSI-H) status. Trans-activation responsive RNA-binding protein 2, an integral component of DICER1-containing complex, was a putative target of DNA mismatch repair deficiency. Truncating mutation has been identified in gastrointestinal cancers with MSI. No previous study has evaluated the mutation status of this gene in MSI UUT-UCs. In this study, we analyze the mutation of TARBP2 in MSI-H UUT-UCs with reverse transcription polymerase chain reaction. No truncating mutations were identified in the MSI-H UUT-UCs.

Mismatch repair hMSH2, hMLH1, hMSH6 and hPMS2 mRNA expression profiles in precancerous and cancerous urothelium

Changes in the expression of the mismatch repair (MMR) genes hMSH2, hMLH1, hMSH6 and hPMS2 reflect dysfunction of the DNA repair system that may allow the malignant transformation of tissue cells. The aim of the present study was to address the mRNA expression profiles of the mismatch DNA repair system in cancerous and precancerous urothelium. This is the first study to quantify MMR mRNA expression by applying quantitative real-time PCR (qPCR) and translate the results to mRNA phenotypic profiles (r, reduced; R, regular or elevated) in bladder tumors [24 urothelial cell carcinomas (UCCs) and 1 papillary urothelial neoplasm of low malignant potential (PUNLMP)] paired with their adjacent normal tissues (ANTs). Genetic instability analysis was applied at polymorphic sites distal or close to the hMSH2 and hMLH1 locus. Presenting our data, reduced hMSH2, hMSH6 and hPMS2 mRNA expression profiles were observed in cancerous and precancerous urothelia. Significantly, the ANTs of UCCs revealed the highest percentages of reduced hMSH2 (r(2)), hMSH6 (r(6)) and hPMS2 (p(2)) mRNA phenotypes relative to their tumors (P<0.03). In particular, combined r(2)r(6) (P<0.02) presented a greater difference between ANTs of low-grade UCCs vs. their tumors compared with ANTs of high-grade UCCs (P= 0.000). Reduced hMLH1 (r(1)) phenotype was not expressed in precancerous or cancerous urothelia. The hMSH6 mRNA was the most changed in UCCs (47.8%), while hMSH2, hMLH1 and hPMS2 showed overexpression (47.8, 35 and 30%, respectively) that was associated with gender and histological tumor grading or staging. Genetic instability was rare in polymorphic regions distal to hMLH1. Our data reveal a previously unrecognized hMSH2 and hMSH6 mRNA combined phenotype (r(2)r(6)) correlated with a precancerous urothelium and show that hMLH1 is transcriptionally activated in precancerous or cancerous urothelium. In the present study, it is demonstrated that reduction of hMSH6 mRNA is a frequent event in bladder tumorigenesis and reflects a common mechanism of suppression with hMSH2, while alterations of hMSH2 or hMLH1 mRNA expression in UCCs does not correlate with the allelic imbalance of polymorphic regions harboring the genes.

Three synchronous primary carcinomas in a patient with HNPCC associated with a novel germline mutation in MLH1: Case report

Background

MLH1 is one of six known genes responsible for DNA mismatch repair (MMR), whose inactivation leads to HNPCC. It is important to develop genotype-phenotype correlations for HNPCC, as is being done for other hereditary cancer syndromes, in order to guide surveillance and treatment strategies in the future.

Case presentation

We report a 47 year-old male with hereditary nonpolyposis colorectal cancer (HNPCC) associated with a novel germline mutation in MLH1. This patient expressed a rare and severe phenotype characterized by three synchronous primary carcinomas: ascending and splenic flexure colon adenocarcinomas, and ureteral carcinoma. Ureteral neoplasms in HNPCC are most often associated with mutations in MSH2 and rarely with mutations in MLH1. The reported mutation is a two base pair insertion into exon 10 (c.866_867insCA), which results in a premature stop codon.

Conclusion

Our case demonstrates that HNPCC patients with MLH1 mutations are also at risk for ureteral neoplasms, and therefore urological surveillance is essential. This case adds to the growing list of disease-causing MMR mutations, and contributes to the development of genotype-phenotype correlations essential for assessing individual cancer risk and tailoring of optimal surveillance strategies. Additionally, our case draws attention to limitations of the Amsterdam Criteria and the need to maintain a high index of suspicion when newly diagnosed colorectal cancer meets the Bethesda Criteria. Establishment of the diagnosis is the crucial first step in initiating appropriate surveillance for colorectal cancer and other HNPCC-associated tumors in at-risk individuals.

Coexistent intraurothelial carcinoma and muscle-invasive urothelial carcinoma of the bladder: clonality and somatic down-regulation of DNA mismatch repair

Muscle-invasive urothelial carcinomas are heterogeneous neoplasms for which the clonal relationship with low-grade urothelial dysplasia and carcinomas in situ remains unknown, and both monoclonal and field change models have been proposed. Low-grade dysplasia (18) and carcinoma in situ (12) associated with muscle-invasive urothelial carcinoma were microdissected and topographically analyzed (intraepithelial and invasive superficial and deep to muscularis mucosa) for methylation pattern of androgen receptor alleles, TP53, RB1, WT1, and NF1 microsatellite analysis to assess clonal identity; MLH1 and MSH2 sequencing/immunostaining. Appropriate controls were run. Carcinoma in situ (100%) and invasive urothelial carcinoma (100%) revealed monoclonal patterns, whereas low-grade dysplasia was preferentially polyclonal (80%). Carcinoma in situ showed aneuploid DNA content and more abnormal microsatellites than the corresponding invasive compartments, opposite to low-grade dysplasia. Absent MLH1 protein expression with no gene mutations were identified in carcinoma in situ and nodular-trabecular urothelial carcinoma with high microsatellite abnormalities. Somatic mismatch repair protein down-regulation and the accumulation of tumor suppressor gene microsatellite abnormalities contribute to a molecular evolution for monoclonal carcinoma in situ divergent from coexistent muscle-invasive urothelial carcinoma. Low-grade dysplasia is however unlikely connected with this molecular progression.

Upper urinary tract urothelial cell carcinomas and other urological malignancies involved in the hereditary nonpolyposis colorectal cancer (lynch syndrome) tumor spectrum

CONTEXT

The data describing the urologic extracolonic cancers associated with hereditary nonpolyposis colorectal cancer (HNPCC) are variable.

OBJECTIVE

Provide an update about the current urologic tumor spectrum in HNPCC.

EVIDENCE ACQUISITION

Data on HNPCC extracolonic tumor spectrum published in the literature were analysed using MEDLINE with emphasis on urological malignancies, upper tract tumors, clinical criteria, genetic diagnosis and counselling.

EVIDENCE SYNTHESIS

HNPCC is a form of colorectal cancer with a dominant autosomal mode of inheritance. HNPCC is caused by germ-line mutations affecting one or several mismatch repair genes. Cancers other than colorectal cancer are sometimes associated with HNPCC. These include specific urological malignancies, most notably tumors of the upper urinary tract, which have been reported to occur at a rate x22 higher than the general population. Upper urinary tract tumors rank third (5%) after colon (63%) and endometrial (9%) cancer within the group of HNPCC related tumors. Prostate cancer and testicular germ cell tumors are rarely associated. Due to lack of appreciation of such hereditary associations, some inherited cancers are still misclassified as sporadic and their incidence is underestimated. The biological tests requested in suspected cases of HNPCC are: microsatellite instability (MSI) analysis, immunohistochemistry and DNA sequencing. When gene mutations are detected, the patient and their family will benefit from a multidisciplinary management approach. The presence of other HNPCC-associated cancers is sought and close monitoring of patients is undertaken. Genetic counselling is provided to the patient's family.

CONCLUSIONS

The recognized urologic tumor spectrum in HNPCC includes upper tract tumors. However, in order not to overlook a hereditary cancer, urologists should be aware of the possible urological malignancies associated with HNPCC (i.e., prostate and testicular carcinomas) and evaluate appropriately anyone they feel are at high risk of underlying HNPCC based on set clinical criteria.

Differential cancer predisposition in Lynch syndrome: insights from molecular analysis of brain and urinary tract tumors

Hereditary non-polyposis colorectal carcinoma (Lynch syndrome) is among the most common hereditary cancers in man and a model of cancers arising through deficient DNA mismatch repair (MMR). Lynch syndrome patients are predisposed to different cancers in a non-random fashion, the basis of which is poorly understood. We addressed this issue by determining the molecular profiles for different tumors from a nationwide cohort of Lynch syndrome families (approximately 150 tumors in total). We focused on some less prevalent cancers, affecting the brain (n = 7) and urinary tract (five bladder and five ureter uroepithelial cancers and four kidney adenocarcinomas), and compared their molecular characteristics to those of the most common cancers, colorectal, gastric and endometrial adenocarcinomas, from the same families. Despite origin from verified MMR gene mutation carriers, the frequency of high-level microsatellite instability in tumors varied between high (100-96% for ureter, stomach and colon), intermediate (63-60% for endometrium and bladder) and low (25-0% for kidney and brain). In contrast to gastrointestinal and endometrial carcinomas, active (nuclear) beta-catenin was rare and KRAS mutations were absent in brain and urological tumors. Compared with other tumors, frequent stabilization of p53 protein characterized urinary tract cancers. Promoter methylation of tumor suppressor genes discriminated the tumors in an organ-specific manner. Our findings suggest that different Lynch syndrome tumors develop along different routes. Uroepithelial cancers of the ureter (and bladder to lesser extent) share many characteristics of MMR deficiency-driven tumorigenesis, whereas brain tumors and kidney adenocarcinomas follow separate pathways.

TGF-betaRII, BAX, IGFIIR, caspase-5, hMSH3 and hMSH6 alterations are not associated with microsatellite instability or p53 mutations in invasive urothelial carcinoma of the urinary bladder

AIM

The aim of this study was to determine the potential synchronous contribution of alterations in TGF-betaRII, BAX, IGFIIR, caspase-5, hMSH3 and hMSH6 genes to the development and clinical outcome of bladder cancer, in relation to p53 mutations, microsatellite status and hMLH1/hMSH2 expression.

METHODS

Molecular biology techniques as well as immunohistochemistry were applied in 69 samples from patients with urothelial carcinoma.

RESULTS

Microsatellite alterations were observed in TGF-betaRII(A)(10 )(16%) and BAX(G)(8 )(3%), irrespective of the presence of p53 mutations, but not in IGFIIR(G)(8), caspase-5(A)(10, ) hMSH3(A)(8) and hMSH6(C)(8). A statistically significant correlation could be found only between hMLH1 expression and the presence of microsatellite instability (Fisher's exact test, p = 0,013). Survival analysis indicated that apart from grade and T-category, hMLH1 expression was the only parameter significantly affecting overall survival (p = 0.021 in univariate and p = 0.015 in multivariate analysis) and recurrence-free survival (p = 0.0463 in univariate and p = 0.022 in multivariate analysis).

CONCLUSIONS

We conclude that alterations of the examined target genes of MSI are rare in urinary bladder carcinoma and they are not associated with microsatellite instability or the presence of p53 mutations.

Spectrum of molecular alterations in colorectal, upper urinary tract, endocervical, and renal carcinomas arising in a patient with hereditary non-polyposis colorectal cancer

Hereditary nonpolyposis colon cancer (HNPCC) syndrome is the most frequent hereditary cancer syndrome predisposing to cancers of various locations, especially colon, endometrium, stomach, and upper urinary tract. Carcinomas of the kidney parenchyma are not considered as an HNPCC-related tumor. HNPCC tumors are characterized by microsatellite instability (MSI) due to a defect in mismatch repair (MMR) and carry somatic frameshift mutations in mononucleotide repeats within the coding regions of key genes. We report the first case of a papillary carcinoma of the kidney in an HNPCC patient who developed carcinomas of the upper urinary tract, endocervix, and colon. Whereas the HNPCC-related tumors demonstrated MSI phenotype, loss of MSH2 protein expression, and frameshift mutations in several of the 13 target genes analyzed, the kidney cancer displayed MSS phenotype, normal MMR protein expression, and no frameshift mutation in target genes. Our observations do not support the possibility that papillary carcinomas are part of HNPCC syndrome.

Microsatellite instability and mutation analysis of candidate genes in urothelial cell carcinomas of upper urinary tract

A subset of upper urinary tract urothelial cell carcinomas (UUC), arising sporadically or as a manifestation of hereditary non-polyposis colorectal cancer, displays microsatellite instability (MSI). MSI tumours are characterized by defective mismatch repair and accumulation of frameshift mutations in numerous genes harbouring repeats in their coding sequences. We have evaluated the incidence of MSI in UUC and the intratumoral distribution of mutations in 13 candidate target genes. A total of 58 unselected UUC were screened for MSI using the panel of five mononucleotide markers recently recommended by the National Cancer Institute for a precise MSI assessment. Four tumours displayed MSI (7%), among which at least three had alterations in the genes MSH3, BAX, MRE11, RAD50. Mutations in genes involved in key cellular pathways (ATR, DNA-PKcs, MBD4, TCF-4, MSH6, and BLM) were further detected. BAX and MRE11 mutations tend to present homogeneously within the three MSI UUC. Immunohistochemistry (MLH1, MSH2, MSH6) showed that loss of mismatch repair protein expression occurred in all MSI UUC defining the gene defect and that MRE11 and RAD50 mutations were associated with their concomitant loss expression. In conclusion, MSI UUC represent a small proportion of UUC in which BAX and MRE11 mutations are frequent and may play a role early in UUC tumorigenesis.