Dataset Information

Comparison of Methods for Testing Mismatch Repair Status in Endometrial Cancer.

ABSTRACT: Approximately 20-30% of endometrial carcinomas (EC) are characterized by mismatch repair (MMR) deficiency (dMMR) or microsatellite instability (MSI), and their testing has become part of the routine diagnosis. The aim of this study was to establish and compare the MMR status using various approaches. Immunohistochemistry (IHC), PCR-based MSI, and the detection of defects in the four key MMR genes (MLH1, PMS2, MSH2, and MSH6) via methylation-specific multiplex ligation-dependent probe amplification (MLPA) and targeted next-generation sequencing (NGS) were performed. MSH3 expression was also evaluated. A set of 126 early-stage EC samples were analyzed, 53.2% of which were dMMR and 46.8% of which were proficient MMR (pMMR) as determined using IHC, whereas 69.3% were classified as microsatellite stable, while 8.8% and 21.9% were classified MSI-low (MSI-L) and MSI-high (MSI-H), respectively. In total, 44.3% of the samples showed genetic or epigenetic alterations in one or more genes; MLH1 promoter methylation was the most common event. Although acceptable concordance was observed, there were overall discrepancies between the three testing approaches, mainly associated with the dMMR group. IHC had a better correlation with MMR genomic status than the MSI status determined using PCR. Further studies are needed to establish solid conclusions regarding the best MMR assessment technique for EC.

SUBMITTER: Mendiola M

PROVIDER: S-EPMC10572657 | biostudies-literature | 2023 Sep

REPOSITORIES: biostudies-literature

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Comparison of Methods for Testing Mismatch Repair Status in Endometrial Cancer.

Mendiola Marta M Heredia-Soto Victoria V Ruz-Caracuel Ignacio I Baillo Amparo A Ramon-Patino Jorge Luis JL Escudero Francisco Javier FJ Miguel Maria M Pelaez-Garcia Alberto A Hernandez Alicia A Feliu Jaime J Hardisson David D Redondo Andres A

International journal of molecular sciences 20230923 19

Approximately 20-30% of endometrial carcinomas (EC) are characterized by mismatch repair (MMR) deficiency (dMMR) or microsatellite instability (MSI), and their testing has become part of the routine diagnosis. The aim of this study was to establish and compare the MMR status using various approaches. Immunohistochemistry (IHC), PCR-based MSI, and the detection of defects in the four key MMR genes (MLH1, PMS2, MSH2, and MSH6) via methylation-specific multiplex ligation-dependent probe amplificati ...[more]

PMID: 37833916

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Project description:The inclusion of DNA mismatch repair (MMR) evaluation as a standard of care for endometrial cancer management will result in a growing population of patients with MMR deficiency and negative germline Lynch syndrome testing (MMR-deficient). In this systematic review and study, the clinicopathologic features of endometrial cancer in patients with MMR-intact, MLH1 methylation positive, MMR-deficient or Lynch syndrome are evaluated. A systematic search of online databases between 1990 and 2018 identified studies of endometrial cancer patients with tumour testing (MMR protein immunohistochemistry or microsatellite instability) and germline assessment for Lynch syndrome. Extracted data included tumour testing, germline genetic testing, age, body mass index (BMI), family history, tumour stage, grade and histologic type. Associations between MMR-intact, MLH1 methylation positive, MMR-deficient and Lynch syndrome groups were analysed using descriptive statistics. The comprehensive search produced 4,400 publications, 29 met inclusion criteria. A total of 7,057 endometrial cancer cases were identified, 1,612 with abnormal immunohistochemistry, 977 with microsatellite instability. Nine-hundred patients underwent germline genetic testing, identifying 212 patients with Lynch syndrome. Patients in the Lynch syndrome and MMR-deficient groups were significantly younger than patients in the MMR-intact and MLH1 methylation positive groups. Patients with MMR-intact tumours had the highest BMI, followed by MMR-deficient, then Lynch syndrome. MMR-intact tumours were more likely to be grade I at diagnosis than other groups. Patients with Lynch syndrome and MMR-deficient tumours were less likely to have stage I disease as compared to patients with MMR-intact tumours. Endometrial cancer patients with MMR-deficient tumours have similar features to those with germline Lynch syndrome mutations, including age, grade, histology and stage. Even in the absence of a germline mutation, tumour evaluation for MMR status may have important clinical implications.

Project description:Background/Objectives: Mismatch repair (MMR) deficiency can be indicative of Lynch syndrome (LS) and guide treatment with immune checkpoint inhibitors. Colorectal cancers (CRCs) and endometrial cancers (ECs) are routinely screened to identify LS, primarily using immunohistochemistry (IHC) or microsatellite instability (MSI) testing, but concordance between these methods is variable in ECs. Here, we investigate this variability in 361 ECs from the Ohio OCCPI/OPTEC (n = 196) and Manchester PETALS (n = 165) trials, where concordance between assays differed significantly. Methods: Samples were re-tested using the amplicon-sequencing-based Newcastle MSI assay (NCL_MSI), and analysed with respect to existing IHC, MSI and MLH1 promoter hypermethylation data. Results: NCL_MSI showed consistency with the Ohio results (94% and 97% concordance with IHC and original MSI assays, respectively) and increased concordance within the Manchester cohort from 78% to 86% (MSI) and 84% (IHC). Among discordant Manchester samples, NCL_MSI was significantly associated with MLH1 promoter methylation status (p = 0.0028) and had the highest concordance with methylation, (62/69 samples, 90%), indicating utility as a screening tool in this tumour type. However, tumours with germline MSH6 defects were only detected efficiently with IHC; seven out of eight LS tumours classified as MSS by either MSI assay had isolated MSH6 loss, compared to four out of twelve classified as MSI-H by both (p = 0.028). Furthermore, reduced MSI signal was observed in tumours with isolated MSH6 loss (p = 0.009 Ohio, p = 6.2 × 10-5 Manchester) and in both ECs and CRCs with germline defects, although this only reached significance in CRCs (p = 0.002). Conclusions: These results provide further evidence that ECs with MSH6 loss in particular and LS tumours in general have an attenuated MSI signal, providing support for current guidelines specifically recommending IHC for LS detection and immune checkpoint therapy assessment in EC.

Project description:ObjectiveMany patients treated with immune checkpoint inhibitors (ICIs) developed primary or secondary drug resistance for unknown reasons. This study investigates whether mismatch repair (MMR) genes are responsible for this therapeutic restriction.MethodsWe obtained the transcriptional, clinical and single nucleotide polymorphism data for endometrial cancer (EC) from The Cancer Genome Atlas and the immunophenoscore data of EC from The Cancer Immunome Atlas, then analyzed in R to evaluate the relationship between MMR genes and clinicopathological features, prognosis, immune infiltration, immune checkpoint expression and responsiveness to ICIs in EC. We used differentially expressed genes in the MSH6 high and low expression groups to conduct GO and KEGG analyses to explore the impact of MSH6 on the biological functions of EC. Finally, we verified the bioinformatics results with in vitro experiments.ResultsOur analyses showed that compared with the high MSH6 expression group, the low MSH6 expression group had better survival outcomes and less aggressive clinicopathological features. In the multivariate Cox analysis, MSH6 was the only independent risk factor that could predict the prognosis of EC. Besides, the low MSH6 expression group also had a higher immune score, more active immune infiltration and higher immune checkpoint expression, resulting in better responsiveness to ICIs treatment, consistent with the enrichment of GO terms and KEGG pathways related to immune response in this group. Meanwhile, the GO and KEGG enrichment results of the MSH6 high expression group were associated with cell cycle, DNA damage repair and tumorigenesis. To exclude the influence of MSH6 mutations, we performed the previous analyses on the MSH6 wild-type tumor samples and obtained consistent results. In vitro experiments also confirmed that after knocking down MSH6 in endometrial cancer cells, their proliferation, migration and invasion abilities were weakened, while the expression levels of PD-L1 and PD-L2 were elevated. In comparison, overexpression of MSH6 showed an opposite trend.ConclusionReduced MSH6 expression could serve as a potential biomarker for predicting better prognosis, active immune status, higher immune checkpoint expression level and better responsiveness to ICIs treatment in EC. MSH6 may become a potential target for treating solid tumors.

Project description:Around 30% of endometrial cancers (EC) are mismatch repair (MMR) deficient, mostly as a consequence of mutations acquired during tumorigenesis, but a significant minority is caused by Lynch syndrome (LS). This inherited cancer predisposition syndrome primes an anti-cancer immune response, even in healthy carriers. We sought to explore the intra-tumoral immunological differences between genetically confirmed LS-associated MMR-deficient (MMRd), sporadic MMR-deficient, and MMR-proficient (MMRp) EC. Endometrial tumors from women with known LS were identified (n = 25). Comparator tumors were recruited prospectively and underwent microsatellite instability (MSI) testing, immunohistochemistry (IHC) for MMR expression and MLH1 methylation testing. Those found to have MLH1 hypermethylation formed the sporadic MMR-deficient group (n = 33). Those found to be mismatch repair proficient and microsatellite stable formed the MMR-proficient group (n = 35). A fully automated monoplex IHC panel was performed on sequential formalin-fixed paraffin-embedded tumor sections to identify CD3+, CD8+, CD45RO+, FoxP3+, and PD-1+ immune cells, and PD-L1 expression by tumor/immune cells. Two independent observers quantified immune marker expression at the tumor center and invasive margin. Mean and overall compartmental T-cell counts generated standard (binary: Low/High) and higher resolution (quaternary: 0-25, 25-50, 50-75, 75-100%) immune scores, which were used as explanatory features in neural network, support vector machine, and discriminant predictive modeling. Overall T-cell counts were significantly different between the three cohorts: CD3+ (p = <0.0001), CD8+ (p = <0.0001), CD45RO+ (<0.0001), FoxP3+ (p = <0.0001), and PD1+ (p = <0.0001), with LS-associated MMR-deficient tumors having highest infiltrations. There were significant differences in CD8+ (p = 0.02), CD45RO+ (p = 0.007), and PD-1+ (p = 0.005) T-cell counts at the invasive margin between LS-associated and sporadic MMR-deficient tumors, but not between sporadic MMR-deficient and MMR-proficient tumors. Predictive modeling could accurately determine MMR status based on CD8+ T-cell counts within the tumor center alone. This study shows that LS-associated and sporadic MMR-deficient EC are distinct immunological entities, which has important implications for treatment and prognosis.

Dataset Information

Comparison of Methods for Testing Mismatch Repair Status in Endometrial Cancer.

Publications

Comparison of Methods for Testing Mismatch Repair Status in Endometrial Cancer.

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