Prognostic value of microsatellite instability determined by immunohistochemical staining of hMSH2 and hMSH6 in urothelial carcinoma of the bladder

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.

Prognostic influence of microsatellite alterations of muscle-invasive bladder cancer treated with radical cystectomy

OBJECTIVE

To examine the prognostic effect of microsatellite instability (MSI) and loss of heterozygosity (LOH) on cancer-specific survival (CSS) in patients with muscle-invasive bladder cancer (MIBC).

PATIENTS AND METHODS

The liquid nitrogen-preserved specimens of 220 patients between March 2009 and December 2012 were analyzed for the presence of MSI and LOH in 12 loci (ACTBP2, D16S310, D16S476, D18S51, D4S243, D9S162, D9S171, D9S747, FGA, INF-α, MBP, MJD) using polymerase chain reaction. MSI was defined as MSI-stable, MSI-Low, or MSI-High if instability was detected in 0, 1, or 2 or more of the examined markers, respectively. The association between MSI-High and LOH and CSS was analyzed using uni- and multivariate analyses and the degree of agreement between tumor and urine samples were determined.

RESULTS

MSI were found in 1030 (39%) and 1148 (43.5%) in tumor and urine specimens, respectively (Kappa = 0.77). On the other hand, LOH was found in 163 (6.2%) of tumor tissues and 44 (1.7%) in urine specimens (Kappa = 0.34). Microsatellite alterations were significantly associated with worse CSS at 1- and 5-year in tumor tissue (95% and 83.7% vs. 65.8% and 3.5%, respectively; P < 0.001) and in urine sample (90% and 64% vs. 46.5% and 9.3%, respectively; P < 0.001). MSI and/or LOH was an independent predictor of CSS (HR: 9.8; 95%CI: 5.1-18.9; P < 0.001).

CONCLUSIONS

Microsatellite alterations were potentially an independent predictor of CSS in patients with MIBC. The agreement was good between tumor and urine MSI but weak for LOH.

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.

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.

A Whole-genome CRISPR Screen Identifies a Role of MSH2 in Cisplatin-mediated Cell Death in Muscle-invasive Bladder Cancer

BACKGROUND

The response to first-line, platinum-based treatment of muscle-invasive bladder cancer has not improved in 3 decades.

OBJECTIVE

To identify genes that influence cisplatin resistance in bladder cancer.

DESIGN, SETTING, AND PARTICIPANTS

We performed a whole-genome CRISPR screen in a bladder cancer cell line to identify genes that mediate resistance to cisplatin.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Targeted validation was performed in two bladder cancer cell lines. The top gene candidate was validated in a publicly available bladder cancer dataset.

RESULTS AND LIMITATIONS

From the CRISPR screen, we identified MSH2 as the most significantly enriched gene and mismatch repair as the most significantly enriched pathway that promoted resistance to cisplatin. Bladder cancer cells with knockdown of MSH2 showed a reduction in cisplatin-mediated apoptosis. MSH2 loss did not impact the sensitivity to other chemotherapies, including the cisplatin analog oxaliplatin. Bladder tumors with low MSH2 protein levels, quantified using reverse-phase protein array, showed poorer survival when treated with cisplatin- or carboplatin-based therapy; these results require future validation using immunohistochemistry. Additionally, results are retrospective from patients with primarily high-grade tumors; thus, validation in a controlled clinical trial is needed.

CONCLUSIONS

We generated in vitro evidence that bladder cancer cell lines depleted of MSH2 are more resistant to cisplatin. We additionally found an association between low MSH2 in bladder tumors and poorer patient survival when treated with platinum-based chemotherapy. If successfully validated prospectively, MSH2 protein level could assist in the selection of patients for chemotherapy.

PATIENT SUMMARY

We report the first evidence that MSH2 protein level may contribute to chemotherapy resistance observed in muscle-invasive bladder cancer. MSH2 has potential as a biomarker predictive of response to platinum-based therapy.

[Recent advances in bladder urothelial carcinogenesis]

Bladder cancer is the sixth cause of cancer mortality in France and prognosis of muscle-invasive tumors remains poor due to lack of effective treatments. Recent advances in molecular biology applied to tumors and results of recent genome-wide studies have brought a important impact on the understanding of bladder carcinogenesis. Main molecular alterations concern FGFR3, TP53 and HER2, and it is now possible to distinguish three subgroups of tumors according to molecular profile. This paper proposes a review of different genetic and epigenetic alterations in bladder cancer, their potential role as theranostic markers in clinical oncology and new targeted therapies according to the concept of personalized medicine.

DNA repair genes and prognosis in sporadic forms of urothelial carcinoma of the upper urinary tract

INTRODUCTION

Lynch syndrome or hereditary nonpolyposis colorectal cancer is caused by mutations in DNA repair genes, known as mismatch repair (MMR) genes, and is associated with microsatellite instability. Urothelial carcinoma of the renal pelvis is also associated with this syndrome. These genetic abnormalities have been described in sporadic forms of upper tract urothelial carcinoma (UTUC).

MATERIAL AND METHOD

This was a descriptive study and survival analysis of a series of 80 patients with sporadic UTUC with no metastases at diagnosis (N0/Nx M0) treated exclusively with nephroureterectomy. We evaluated the expression of MMR genes (hMLH1, hPMS2, hMSH2 and hMSH6) in sections performed with tissue microarray (TMA) and their association with clinical-pathological parameters. We analyzed the prognostic value of the loss of expression of these genes in UTUC.

RESULTS

We detected no loss of MSH2 or of MSH6, but there was a loss of MLH1 in 11 cases (13.8%) and of PMS2 in 21 cases (26.3%). The expression of hMLH1 and hPMS2 were strongly associated (P<.0001), and this phenotype expression entails significant clinical implications. The loss of MLH1 was associated with a low grade (P=.02). Loss of PMS2 was associated with a lower stage (P=.05), a pushing pattern with no invasive edges (P=.008) and less angiogenesis (P=.008). The inactivation of hPMS2 or hMLH1 is an independent protective factor (HR, 0.309) and, along with the histologic grade (HR, 5.561), defines the patients' prognosis.

CONCLUSION

In our experience, the inactivation of hPMS2 or hMLH1 is an independent marker of good prognosis and occurs in a quarter of sporadic UTUC cases. The immunohistochemical study of these patients can be used to assess the screening of hidden forms of Lynch syndrome.

Low expression of MSH2 DNA repair protein is associated with poor prognosis in head and neck squamous cell carcinoma

Objective

This study aimed to investigate the expression of the MSH2 DNA repair protein in head and neck squamous cell carcinoma (HNSCC) in order to analyze its association with clinicopathologic factors and overall survival of patients.

Material and Methods

Clinical data and primary lesions of HNSSC were collected from 55 patients who underwent surgical resection with postoperative radiotherapy in Montes Claros, state of Minas Gerais, Brazil, between 2000 and 2008. Immunohistochemical reactions were performed to analyze MSH2 protein expression.

Results

Bivariate analysis showed no significant correlation or association between MSH2 expression and clinicopathologic parameters by Mann-Whitney and Kruskal-Wallis tests. Patients with locoregional metastatic disease (OR=4.949, p<0.001) and lower MSH2 immunohistochemical expressions (OR=2.943, p=0.032) presented poorer survival for HNSCC by Cox regression models.

Conclusions

Our data demonstrated that lower MSH2 expression might contribute to a higher clinic aggressiveness of HNSCC by promoting an unfavorable outcome.

[Muscle invasive bladder cancer after radical cystectomy. Prognostic factors of adjuvant chemotherapy]

BACKGROUND

The indications to administer adjuvant systemic chemotherapy to patients with urothelial carcinoma of the bladder who underwent radical cystectomy is discussed controversially and all international guidelines are very restrictive with regard to its recommendation for routine daily practice due to the low scientific evidence concerning its therapeutic benefit. Currently, adjuvant systemic chemotherapy should be preferably administered within clinical trials. In the daily routine adjuvant treatment might be given in patients with lymph node positive disease. Clinical, pathohistological and molecular biomarkers which might be associated with a positive or negative treatment response have been evaluated sparsely in the past.

RESULTS

The presence of hemangiosis/lymphangiosis carcinomatosa and/or extranodal expansion in patients with lymph node metastases appears to be associated with a poor outcome. The markers ERCC-1, XAF and anti-apoptotic proteins of the Bcl-2 family seem to represent the most promising biomarkers associated with response to adjuvant cisplatin-based chemotherapy.

Immunohistochemical analysis of mismatch proteins in carcinogenesis of the lower lip

AIM

This study investigated the immunohistochemical expression of hMLH1 and hMSH2 proteins in lower lip squamous cell carcinoma (SCC) and actinic cheilitis (AC), to contribute to the understanding of the development of lower lip cancer.

METHODS AND RESULTS

Forty cases of lower lip AC and SCC were studied. Quantitative immunohistochemical analysis was undertaken by counting 1000 cells (positive and negative) in each lesion. Statistical evaluation included Student's t-test and one-way ANOVA. For SCC and AC, the mean number of hMLH1- and hMSH2-positive cells decreased with advanced stage of the lesion. The largest mean number of immunostained cells was observed in AC cases without dysplasia or with mild dysplasia (hMLH1: 721.23 ± 88.116; hMHS2: 781.50 ± 156.93). Intermediate values were obtained for AC with moderate or severe dysplasia (hMLH1: 532.86 ± 197.72; hMHS2: 611.14 ± 172.48). Lower lip SSCs presented the smallest number of positive cells (hMLH1: 255.03 ± 199.47; hMHS2: 518.38 ± 265.68). A statistically significant difference was observed between groups (P < 0.001).

CONCLUSIONS

The results support the hypothesis that changes in the immunoexpression of these mismatch proteins are related to the process of carcinogenesis of the lower lip.

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.