Low frequency of HNPCC-associated microsatellite instability and aberrant MMR protein expression in early-onset bladder cancer

Clinical features and oncological outcomes of bladder cancer microsatellite instability

OBJECTIVES

Excellent anticancer effect for solid tumors with microsatellite instability (MSI)-high by anti-PD-1 antibody has been reported. In this study, we investigated the clinical impact of MSI status in bladder cancer.

METHODS

This study included 205 Japanese patients who underwent transurethral resection for bladder cancer between 2005 and 2021. The prevalence rates of microsatellite stable (MSS), MSI-low (MSI-L), and MSI-high (MSI-H) were determined using molecular testing. We examined the association of MSI status (MSS versus MSI-L/H) with clinicopathological characteristics and oncological outcomes.

RESULTS

MSI-L/H tumors were associated with higher T-category in non-muscle invasive bladder cancer (NMIBC). Additionally, MSI-L/H tumors were associated with a higher risk of intravesical recurrence in NMIBC patients treated with intravesical bacillus Calmette-Guérin (BCG) but not with non-BCG therapy.

CONCLUSIONS

This study suggested that the MSI status might serve as a predictive marker for intravesical recurrence after BCG intravesical therapy in NMIBC and highlighted an unmet need for an alternative treatment in patients with MSI-L/H tumors.

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.

Role of PD-1/PD-L1-mediated tumour immune escape mechanism and microsatellite instability in the BCG failure of high-grade urothelial carcinomas

BACKGROUND

Intravesical BCG treatment fails inexplicably in 30%-45% of patients for high-grade nonmuscle-invasive bladder cancer (NMIBC). We aimed to investigate the role of PD-1/PD-L1 interaction on BCG failure of high-grade NMIBC and to identify biomarkers for predicting BCG responsive cases.

METHODS

Thirty BCG responsive and 29 nonresponsive NMIBCs were included in the study. Expressions of PDL1(SP-263), MSH2, MSH6, PMS2, and MLH1 were evaluated on pre- and post-BCG transurethral resection (TUR-B) specimens by immunohistochemistry. PD-L1(SP-263) expression was categorised as negative/low, high. DNA mismatch repair protein (MMR) expressions were classified as "reduced" if ≤30% of nuclei stained, "preserved" if >30% of nuclei stained. Microsatellite instability (MSI) testing was performed by PCR using five mononucleotide markers.

RESULTS

Reduced DNA MMR protein expression was found to be significantly higher in the pretreatment biopsies of BCG-responsive group than the BCG nonresponsive tumour group (p = 0.022). PD-L1 expression did not show any significant difference between the pre- and posttreatment TUR-B specimens of the BCG nonresponsive tumour group or between the pretreatment TUR-B specimens of BCG nonresponsive and the BCG responsive groups (p = 0.508, p = 0.708, respectively).

DISCUSSION

Immune escape of tumour cells by PD-1/PD-L1 interaction does not seem to have any role in BCG failure of NMIBCs. Reduced MMR expression may help to determine cases that will respond well to BCG therapy. A better antitumour activity of BCG in NMIBCs with reduced MMR expression may be related to the ongoing accumulation of cancer neoantigens in correlation with increased tumour mutation load as a result of DNA repair defects.

Identification of Lynch syndrome-associated DNA mismatch repair-deficient bladder cancer in a Japanese hospital-based population

BACKGROUND

The prevalence of Lynch syndrome (LS)-associated DNA mismatch repair (MMR)-deficient bladder cancer (BC) has scarcely been investigated.

METHODS

Immunohistochemistry for four MMR proteins (MLH1, MSH2, MSH6, and PMS2) was performed in formalin-fixed paraffin-embedded (FFPE) sections prepared from the resected specimens of 618 consecutive newly diagnosed BC cases. Genetic/epigenetic analyses were performed in patients displaying the loss of any MMR proteins in the tumor.

RESULTS

Of the 618 patients, 9 (1.5%) showed the loss of MMR protein expression via immunohistochemistry; specifically, 3, 3, 2, and 1 patients displayed the loss of MLH1/PMS2, PMS2, MSH6, and MSH2/MSH6, respectively. All nine patients were male with a median age of 68 years (63-79 years). One had been previously diagnosed as having LS with an MSH2 variant. Genetic testing demonstrated the presence of a pathogenic PMS2 variant (n = 1), a variant of uncertain significance in MSH2 (n = 1), and no pathogenic germline variants of the MMR genes (n = 1). One patient with MSH6-deficient BC did not complete the genetic testing because of severe degradation of DNA extracted from the FFPE specimen, but the patient was strongly suspected to have LS because of their history of colon cancer and MSH6-deficient upper urinary tract cancer. There remained a possibility that the remaining four patients who refused genetic testing had LS.

CONCLUSIONS

The prevalence of LS-associated MMR-deficient BC was estimated to be 0.6-1.1% among unselected BC cases.

The association between the histopathological features and microsatellite instability in young patients with urothelial carcinoma of the bladder

OBJECTIVE

Bladder cancer under the age of 40 is extremely rare. Bladder cancer development involves complex and multi-stage processes, one of which is the DNA damage repair mechanism. In this retrospective study, we aimed to evaluate the histopathological features of bladder urothelial carcinoma seen in patients under 40 years of age and tumor microsatellite instability status using immunohistochemistry.

METHODS

A total of 50 patients under the age of 40 with urothelial bladder carcinoma from two different centers in the same country were included. Expression of the mismatch repair proteins MLH1, MSH2, MSH6, and PMS2 was analyzed by immunohistochemistry.

RESULTS

Age at the time of diagnosis ranged from 17 to 40 years old. Most tumors were non-invasive papillary urothelial carcinoma. Two cases had nuclear loss of MSH-6 and PMS-2. We observed that tumor grade, tumor stage, presence of tumor differentiation, and infiltrative growth pattern of the tumor have significant impact on prognosis, but microsatellite instability does not have an effective role in bladder carcinogenesis in young patients.

CONCLUSIONS

Our results indicate that the presence of microsatellite instability is not related to the low tumor grade and stage in urothelial neoplasms in young patients, suggesting that urothelial carcinoma of the bladder in young patients may represent a genetically stable form of neoplasia.

How Should We Test for Lynch Syndrome? A Review of Current Guidelines and Future Strategies

International guidelines for the diagnosis of Lynch syndrome (LS) recommend molecular screening of colorectal cancers (CRCs) to identify patients for germline mismatch repair (MMR) gene testing. As our understanding of the LS phenotype and diagnostic technologies have advanced, there is a need to review these guidelines and new screening opportunities. We discuss the barriers to implementation of current guidelines, as well as guideline limitations, and highlight new technologies and knowledge that may address these. We also discuss alternative screening strategies to increase the rate of LS diagnoses. In particular, the focus of current guidance on CRCs means that approximately half of Lynch-spectrum tumours occurring in unknown male LS carriers, and only one-third in female LS carriers, will trigger testing for LS. There is increasing pressure to expand guidelines to include molecular screening of endometrial cancers, the most frequent cancer in female LS carriers. Furthermore, we collate the evidence to support MMR deficiency testing of other Lynch-spectrum tumours to screen for LS. However, a reliance on tumour tissue limits preoperative testing and, therefore, diagnosis prior to malignancy. The recent successes of functional assays to detect microsatellite instability or MMR deficiency in non-neoplastic tissues suggest that future diagnostic pipelines could become independent of tumour tissue.

Biomarkers and intermediate-high risk non-muscle invasive bladder cancer: a multivariate analysis of three different cellular pathways with pronostic implications

PURPOSE

To determine the presence of a group of mutations, and establish the prognostic value for recurrence and progression.

MATERIALS AND METHODS

Prospective observational study. Intermediate-to-high-risk non-muscle invasive bladder cancer (NMIBC) was evaluated. Data from genetic analyses were included in a database along with clinicopathological variables of interest.

RESULTS

Seventy-four patients. Twenty-five (33.8%) recurred and 3 (4.1%) progressed. Median time to recurrence: 8 months (5.7-12.7). Median time to progression: 14 months (P75: 12). Mutation distribution: KRAS codon 12: one patient (1.4%), BAT25: five patients (6.8%), BAT-26: four patients (5.4%), and D2S123: 6 patients (8.1%). Arg72Pro polymorphism: 50 patients (67.6%) exhibited homozygous mutations, 23 (31.1%) were heterozygous, and 1 patient (1.4%) did not present the mutation. We found an association between presence of MSI at BAT26 and female sex (p < 0.05) and tumor stage and the TP53 Arg72Pro polymorphism. Recurrence-free survival (RFS) was significantly associated with presence of MSI at D2S123, with a HR of 5.44 for patients presenting the mutation (95% CI 1.83-16.16). On multivariate analysis, we found a statistically significant increase in risk of recurrence among patients with MSI at D2S123 (HR 5.15; p < 0.05) and more than 2 previous transurethral bladder resections (TURBs) (HR 5.07; p < 0.05) adjusted for tumor stage and grade. Harrell's concordance index revealed an accuracy of 0.74 (p < 0.05).

CONCLUSION

An association was found between presence BAT26 MSI and female sex, Arg72Pro polymorphism with tumor stage and D2S123 and more than 2 TUR procedures were associated with RFS adjusted to tumor stage and grade.

Inverted urothelial papilloma of the upper urinary tract: description of two cases with systematic literature review

BACKGROUND

Inverted urothelial papilloma (IUP) of the upper urinary tract is an uncommon benign tumour that occasionally presents as a polypoid mass causing urinary obstruction. Histologically, IUP is characterised by a proliferating urothelium arranged in cords and trabeculae, in continuity with overlying intact epithelium, and extending into the lamina propria in a non-invasive, endophytic manner. Cytological atypia is minimal or absent. Top differential diagnoses include urothelial carcinoma with inverted growth pattern and florid ureteritis cystica. Although urothelial carcinomas of the upper urinary tract with prominent inverted growth pattern commonly harbour microsatellite instability, the role of the mutator phenotype pathway in IUP development is still unclear. The aim of this study was to describe two additional cases of IUP of the upper urinary tract, along with an extensive literature review.

CASE PRESENTATION

We observed two polypoid tumours originating in the renal pelvis and the distal ureter, respectively. Both patients, a 76-year-old woman and a 56-year-old man, underwent surgery because of the increased likelihood of malignancy. Histology was consistent with IUP and patients are alive and asymptomatic after long-term follow-up (6 years for the renal pelvis lesion and 5 years for the ureter lesion). The tumours retained the expression of the mismatch-repair protein MLH1, MSH2, and PMS2 whereas loss of MSH6 was found in both cases.

CONCLUSIONS

When completely resected, IUP does not require rigorous surveillance protocols, such as those for urothelial carcinoma and exophytic urothelial papilloma. It is therefore important for the surgical pathologist to be aware of this rare entity in order to ensure correct patient management.

Immunohistochemical evaluation of mismatch repair proteins and p53 expression in extrauterine carcinosarcoma/sarcomatoid carcinoma

Introduction

Carcinosarcoma (CS) is a tumor with components: epithelial (carcinomatous) and mesenchymal (sarcomatous), developing in the mechanism of epithelial-mesenchymal transition. It is known that the p53 defect is a frequent finding in a carcinosarcoma in different anatomical locations, additionally, in a subgroup of uterine CS MMR defect plays a role in the pathogenesis. The aim of this paper was to investigate the frequency of MMR and p53 aberrations in extrauterine CS.

Material and methods

Twenty eight extrauterine CS from the lung (n = 8), breast (n = 6), head and neck (n = 5), ovary (n = 3), urinary bladder (n = 3), adrenal gland (n = 1), skin (n = 1), and stomach (n = 1) were stained for hMLH1, PMS2, hMSH2, hMSH6 and p53. The pattern of expression was evaluated separately in carcinomatous and sarcomatous component.

Results

Immunostainings for hMLH1, PMS2, hMSH2 and hMSH6 were positive in all tumors. p53 defect was observed in 19 out of 28 samples (67.85%). In all cases except one (96.42%) there was a concordance between sarcomatoid and carcinomatous components.

Conclusions

MMR deficiency does not seem to play a role in the pathogenesis of extrauterine CS. p53 aberrant expression is frequent and almost always consistent in carcinomatous and sarcomatous component.

MMR deficiency in urothelial carcinoma of the bladder presents with temporal and spatial homogeneity throughout the tumor mass

BACKGROUND

Microsatellite instability (MSI), a hypermutator phenotype described in many cancers, has emerged as a predictive biomarker for immune checkpoint inhibitor therapy. Cancer heterogeneity represents a potential obstacle for the analysis of predicitive biomarkers. MSI has been reported in bladder cancer, but data on the possible extent of intratumoral heterogeneity are lacking.

METHODS

To study MSI heterogeneity in bladder cancer, a tissue microarray (TMA) comprising 598 muscle-invasive urothelial carcinomas of the bladder was utilized to screen for MSI by immunhistochemistry with antibodies for MLH1, PMS2, MSH2, and MSH6.

RESULTS

In 9 cases suspicious for MSI, MMR status was further evaluated by large section examination and polymerase chain reaction (PCR)-based analysis of microsatellites ("Bethesda panel") resulting in the identification of 5 validated MSI cases from 448 interpretable cancers (prevalence 1.1%). MMR deficiency always involved PMS2 loss, in 3 cases with additional loss or reduction of MLH1 expression. Four cancers were MSI-high and 1 was MSI-low in the PCR analysis. Parallel sequencing revealed an inactivating MLH1 mutation in 1 tumor but no further known pathogenic MMR gene mutations were found. Immunostaining of all available 72 cancer-containing tissue blocks of the 5 confirmed bladder cancer with MSI including prior and subsequent biopsies showed complete homogeneity of the MMR protein defects and the status of the 4 MMR proteins did not markedly change in sequential resections. In all 4 cases with noninvasive precursor lesions, MSI was also detectable.

CONCLUSION

These data suggest that MSI occurs early in invasive bladder cancer and immunohistochemical MMR analysis on limited biopsy material is sufficient to estimate MMR status of the entire cancer mass.

Familial/inherited cancer syndrome: a focus on the highly consanguineous Arab population

The study of hereditary cancer, which accounts for ~10% of cancer cases worldwide is an important subfield of oncology. Our understanding of hereditary cancers has greatly advanced with recent advances in sequencing technology, but as with any genetic trait, gene frequencies of cancer-associated mutations vary across populations, and most studies that have located hereditary cancer genes have been conducted on European or Asian populations. There is an urgent need to trace hereditary cancer genes across the Arab world. Hereditary disease is particularly prevalent among members of consanguineous populations, and consanguineous marriages are particularly common in the Arab world. There are also cultural and educational idiosyncrasies that differentiate Arab populations from other more thoroughly studied groups with respect to cancer awareness and treatment. Therefore, a review of the literature on hereditary cancers in this understudied population was undertaken. We report that BRCA mutations are not as prevalent among Arab breast cancer patients as they are among other ethnic groups, and therefore, other genes may play a more important role. A wide variety of germline inherited mutations that are associated with cancer are discussed, with particular attention to breast, ovarian, colorectal, prostate, and brain cancers. Finally, we describe the state of the profession of familial cancer genetic counselling in the Arab world, and the clinics and societies dedicated to its advances. We describe the complexities of genetic counselling that are specific to the Arab world. Understanding hereditary cancer is heavily dependent on understanding population-specific variations in cancer-associated gene frequencies.

Microsatellite instability: a review of what the oncologist should know

The patients with high microsatellite instability (MSI-H)/mismatch repair deficient (dMMR) tumors recently have been reported that can benefit from immunotherapy, and MSI can be used as a genetic instability of a tumor detection index. However, many studies have shown that there are many heterogeneous phenomena in patients with MSI tumors in terms of immunotherapy, prognosis and chemotherapy sensitivity. Here we mainly review the research results of MSI detection methods, the mechanisms of MSI occurrence and its relationship with related tumors, aiming to make a brief analysis of the current research status of MSI and provide comparable reference and guidance value for further research in this field.

Correlation of mismatch repair protein deficiency, PD-L1 and CD8 expression in high-grade urothelial carcinoma of the bladder

Mismatch repair-deficient (d-MMR) tumours have been reported to show susceptibility to immune checkpoint inhibitors targeting programmed death-1/PD ligand-1 (PD-1/PD-L1). In this study, we sought to correlate the association of d-MMR, PD-L1 and CD8 expression in muscle invasive, high-grade urothelial carcinoma (HGUC) of bladder. A tissue microarray (TMA) was constructed from 201 cases and sequentially stained with PD-L1, CD8, MSH2, MSH6, MLH1 and PMS2. PD-L1 was assessed in tumour and immune cells. CD8 was assessed in a hotspot fashion with results averaged across cores. Loss of nuclear MMR expression on TMA sections was further assessed using corresponding whole tissue sections. d-MMR was identified in four cases (2%). The mean CD8 count was significantly higher in d-MMR tumours (10 vs 35, p=0.007) as was the proportion of PD-L1 positivity (75% vs 20%, p=0.031). d-MMR is uncommon in HGUC of bladder but shows strong correlation with cytotoxic T lymphocyte infiltration and PD-L1 tissue expression.

Clinical significance of chromodomain helicase/ATPase DNA binding protein 1-like and human mutL homolog 1 gene expression in cholangiocarcinoma

Cholangiocarcinoma is a highly malignant form of gastrointestinal cancer with an unfavorable prognosis. The novel oncogene chromodomain helicase/ATPase DNA binding protein 1-like (CHD1L) has been confirmed to serve a vital role in numerous types of cancer, including liver cancer. Mismatch repair (MMR) is a common DNA repair process that contributes to the preservation of the integrity and stability of genetic substances. Human mutL homolog 1 gene (hMLH1) is an important MMR protein family member. The present study aimed to evaluate the pathological and clinical features of cholangiocarcinoma, and to investigate the clinical significance of CHD1L and hMLH1 expression in cholangiocarcinoma. A total of 108 samples from cholangiocarcinoma tumor tissues and 60 samples from normal bile duct tissue were obtained from patients admitted to The Second Affiliated Hospital of Nanchang University between May 2005 and May 2014. All cholangiocarcinoma cases were pathologically confirmed. The expression of CHD1L and hMLH1 was examined by immunohistochemistry analysis. The expression of CHD1L in cholangiocarcinoma (94.44%) was significantly higher than in normal bile duct tissues (40.00%). CHD1L expression was associated with gallstone history, serum carbohydrate antigen 19-9 (CA19-9) level and Tumor-Node-Metastasis (TNM) stage (P<0.05). hMLH1 expression in cholangiocarcinoma (77.78%) was significantly lower than in normal bile duct tissues (96.67%), and was associated with gender, age, serum CA19-9 level, the presence of hepatitis B virus surface antigen, TNM stage and tumor diameter (P<0.05). Kaplan-Meier survival curve analysis indicated that the 3-year accumulative survival rates for CHD1L-positive and -negative patients differed significantly (P<0.05; 17.90 and 83.33%, respectively). There was no statistically significant difference (P>0.05) between the 3-year accumulate survival rates for hMLH1-positive and -negative patients (38.90 and 33.30%, respectively). High CHD1L expression and low hMLH1 expression levels were observed in patients with cholangiocarcinoma, and their abnormal expression patterns were associated with the progression of malignancy and an unfavorable disease prognosis. Therefore, CHD1L and hMLH1 may be potential prognostic biomarkers for cholangiocarcinoma.

CD8 lymphocytes in tumors and nonsynonymous mutational load correlate with prognosis of bladder cancer patients treated with immune checkpoint inhibitors

Background

Anti–programed cell death 1 checkpoint inhibitors have recently demonstrated effectiveness against metastatic cancers including urothelial carcinoma.

Aims

To identify biomarkers/factors that correlate with the clinical response in advanced bladder cancer patients who received immune checkpoint inhibitor treatment.

Methods and results

We investigated tumors from 18 bladder cancer patients who had received anti–programed cell death 1 (pembrolizumab) or anti–programmed death‐ligand 1 therapy (atezolizumab or durvalumab) and performed exome analysis, T‐cell receptor sequencing of the tumor‐infiltrating lymphocytes (TILs), and immunohistochemical analysis of CD8 and programmed death‐ligand 1 in cancer tissues. Immunohistochemical analysis of bladder cancer tissues demonstrated that a higher number of CD8 T‐cell infiltration into cancer tissues was significantly associated with longer cancer‐specific survival of the patients (P = .0012). T‐cell receptor beta sequencing of TILs using genomic DNAs extracted from the tissues of 15 cases revealed that patients with higher clonal expansion of TILs had some tendency of longer cancer‐specific survival (P = .055), than those with lower clonal expansion. We performed whole exome sequencing of 14 cases and found that patients carrying higher numbers of somatic mutations received greater benefit from immunotherapy (P = .034) and one patient who had high microsatellite instability has survived for 1034 days.

Conclusion

CD8 infiltration in tumors and nonsynonymous mutation load might be useful predictive markers for immune checkpoint inhibitors for bladder cancer patients.

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.