Mismatch repair deficiency and clinicopathological characteristics in endometrial carcinoma: a systematic review and meta-analysis

Deficient Mismatch Repair and Microsatellite Instability in Solid Tumors

The integrity of the genome is maintained by mismatch repair (MMR) proteins that recognize and repair base mismatches and insertion/deletion errors generated during DNA replication and recombination. A defective MMR system results in genome-wide instability and the progressive accumulation of mutations. Tumors exhibiting deficient MMR (dMMR) and/or high levels of microsatellite instability (termed "microsatellite instability high", or MSI-H) have been shown to possess fundamental differences in clinical, pathological, and molecular characteristics, distinguishing them from their "microsatellite stable" (MSS) counterparts. Molecularly, they are defined by a high mutational burden, genetic instability, and a distinctive immune profile. Their distinct genetic and immunological profiles have made dMMR/MSI-H tumors particularly amenable to treatment with immune checkpoint inhibitors (ICIs). The ongoing development of biomarker-driven therapies and the evaluation of novel combinations of immune-based therapies, with or without the use of conventional cytotoxic treatment regimens, continue to refine treatment strategies with the goals of maximizing therapeutic efficacy and survival outcomes in this distinct patient population. Moreover, the resultant knowledge of the mechanisms by which these features are suspected to render these tumors more responsive, overall, to immunotherapy may provide information regarding the potential optimization of this therapeutic approach in tumors with proficient MMR (pMMR)/MSS tumors.

Refining of cancer-specific genes in microsatellite-unstable colon and endometrial cancers using modified partial least square discriminant analysis

Despite similarities in microsatellite instability (MSI) between colon and endometrial cancer, there are many clinically important organ-specific features. The molecular differences between these 2 MSI cancers are underexplored because the usual differentially expressed gene analysis yields too many noncancer-specific normally expressed genes. We aimed to identify cancer-specific genes in MSI colorectal adenocarcinoma (CRC) and MSI endometrial carcinoma (ECs) using a modified partial least squares discriminant analysis. We obtained a list of cancer-specific genes in MSI CRC and EC by taking the intersection of the genes obtained from tumor samples and normal samples. Specifically, we obtained publically available 1319 RNA sequencing data consisting of MSI CRCs, MSI ECs, normal colon including the rectum, and normal endometrium from The Cancer Genome Atlas and genome-tissue expression sites. To reduce gene-centric dimensions, we retained only 3924 genes from the original data by performing the usual differentially expressed gene screening for tumor samples using DESeq2. The usual partial least squares discriminant analysis was performed for tumor samples, producing 625 genes, whereas for normal samples, projection vectors with zero covariance were sampled, their weights were square-summed, and genes with sufficiently high values were selected. Gene ontology (GO) term enrichment, protein-protein interaction, and survival analyses were performed for functional and clinical validation. We identified 30 cancer-specific normal-invariant genes, including Zic family members (ZIC1, ZIC4, and ZIC5), DPPA2, PRSS56, ELF5, and FGF18, most of which were cancer-associated genes. Although no statistically significant GO terms were identified in the GO term enrichment analysis, cell differentiation was observed as potentially significant. In the protein-protein interaction analysis, 17 of the 30 genes had at least one connection, and when first-degree neighbors were added to the network, many cancer-related pathways, including MAPK, Ras, and PI3K-Akt, were enriched. In the survival analysis, 16 genes showed statistically significant differences between the lower and higher expression groups (3 in CRCs and 15 ECs). We developed a novel approach for selecting cancer-specific normal-invariant genes from relevant gene expression data. Although we believe that tissue-specific reactivation of embryonic genes might explain the cancer-specific differences of MSI CRC and EC, further studies are needed for validation.

Guidelines of the Brazilian Society of Surgical Oncology for anatomopathological, immunohistochemical, and molecular testing in female tumors

INTRODUCTION

Precision medicine has revolutionized oncology, providing more personalized diagnosis, treatment, and monitoring for patients with cancer. In the context of female-specific tumors, such as breast, ovarian, endometrial, and cervical cancer, proper tissue collection and handling are essential for obtaining tissue, immunohistochemical (IHC), and molecular data to guide therapeutic decisions.

OBJECTIVES

To establish guidelines for the collection and handling of tumor tissue, to enhance the quality of samples for histopathological, IHC, genomic, and molecular analyses. These guidelines are fundamental in informing therapeutic decisions in cancer treatment.

METHOD

The guidelines were developed by a multidisciplinary panel of renowned specialists between June 12, 2013 and February 12, 2024. Initially, the panel deliberated on critical and controversial topics related to conducting precision medicine studies focusing on female tumors. Subsequently, 22 pivotal topics were identified within the framework and assigned to groups. These groups reviewed relevant literature and drafted preliminary recommendations. Following this, the recommendations were reviewed by the coordinators and received unanimous approval. Finally, the groups made the final adjustments, classified the level of evidence, and ranked the recommendations.

CONCLUSION

The collection of surgical samples requires minimum quality standards to enable histopathological, IHC, genomic, and molecular analyses. These analyses provide crucial data for informing therapeutic decisions, significantly impacting potential survival gains for patients with female tumors.

Mismatch Repair Protein Deficiency Does Not Affect Disease Free Survival in Type I Endometrial Carcinoma

BACKGROUND

This study aimed to analyze the correlation between the 3-year disease-free survival (DFS) and mismatch repair (MMR) protein levels in patients with type 1 endometrial carcinoma. Many studies have reported different results regarding the role of MMR in the prognosis of endometrial carcinoma; therefore, we aimed to identify this association in our hospital.

METHODS

This observational study employed a historical cohort design and included patients with type 1 endometrial carcinoma who underwent surgery at Dr. Soetomo Hospital between January 2017 and December 2019. Medical records and paraffin blocks meeting these criteria were obtained. MMR proteins (MLH1 and MSH2) were assessed using immunohistochemistry.

RESULTS

A total of 46 patients with type 1 endometrial carcinoma were analyzed. We observed MMR deficiency (dMMR) in 12 patients (26.1%) and MMR proficiency (pMMR) in 34 patients (73.9%). Of the 12 patients with dMMR, nine cases (75%) were diagnosed as stage I and 7 (58.33%) as low grade. The 3-year DFS in patients with dMMR and pMMR was 83.3% and 67.6%, respectively (Hazard Ratio 2.31, 95% CI 0.5135-10.475, p=0.27). Higher stages had a 5.42 times increased risk of recurrence (95% CI 1.3378-21.9358, p=0.018). Higher histopathological grades were also associated with 8.65 times increased risk of recurrence (95% CI 2.5020-29.8738, p=0.001).

CONCLUSION

Patients with dMMR had a better DFS compared to those with pMMR; however, the difference was not statistically significant. The tumor stage and histopathological grade were independent risk factors for recurrence.

Mesonephric-like Adenocarcinoma of the Uterine Corpus: Genomic and Immunohistochemical Profiling with Comprehensive Clinicopathological Analysis of 17 Consecutive Cases from a Single Institution

Data on genetic and immunophenotypical characteristics of uterine mesonephric-like adenocarcinoma (MLA) remain limited. Therefore, we aimed to investigate the clinicopathological, immunohistochemical, and molecular features of uterine MLA. We performed targeted sequencing, array comparative genomic hybridization, and immunostaining in 17, 13, and 17 uterine MLA cases, respectively. Nine patients developed lung metastases. Eleven patients experienced disease recurrences. The most frequently mutated gene was Kirsten rat sarcoma viral oncogene homolog (KRAS; 13/17). Both the primary and matched metastatic tumors harbored identical KRAS (3/4) and phosphatase and tensin homolog deleted on chromosome 10 (1/4) mutations, and did not harbor any additional mutations. A total of 2 of the 17 cases harbored tumor protein 53 (TP53) frameshift insertion and deletion, respectively. Chromosomal gains were detected in 1q (13/13), 10 (13/13), 20 (10/13), 2 (9/13), and 12 (6/13). Programmed cell death-ligand 1 overexpression or mismatch repair deficiency was not observed in any of the cases. Initial serosal extension and lung metastasis independently predicted recurrence-free survival with hazard ratios of 6.30 and 7.31, respectively. Our observations consolidated the clinicopathological and molecular characteristics of uterine MLA. Both clinicians and pathologists should consider these features to make an accurate diagnosis of uterine MLA and to ensure appropriate therapeutic management of this rare entity.

Clinicopathological characteristics of endometrial carcinomas according to DNA mismatch repair protein status

DNA mismatch repair protein deficiency (MMRd) in endometrial carcinoma is associated with the risk of Lynch syndrome and response to immune checkpoint inhibitors. It is also related to microsatellite instability and corresponds to a molecular subtype of endometrial tumor with an unclear prognosis. Here, we evaluated the clinicopathological characteristics and prognosis of 312 consecutive endometrial carcinoma cases submitted to complete surgical staging at a single institution. We compared MMRd and mismatch repair protein-proficient (MMRp) tumors and examined the effects of the MMR protein loss type (MLH1/PMS2 vs. MSH2/MSH6) and influence of L1CAM and p53 expression. The median follow-up period was 54.5 (range, 0-120.5) months. No difference was observed between MMRd [n = 166 (37.2%)] and MMRp [n = 196 (62.8%)] cases in terms of age, body mass index, FIGO stage, tumor grade, tumor size, depth of myometrial infiltration, or lymph node metastasis. More MMRd than MMRp tumors had endometrioid histology (87.9% vs. 75.5%) and despite MMRd had more lymphovascular space invasion (LVSI; 27.2% vs. 16.9%), they presented fewer recurrences and no difference in lymph node metastasis and disease-related death. Relative to those with MLH1/MSH6 loss, tumors with MSH2/MSH6 loss were diagnosed at earlier FIGO stages, were smaller, and had less ≥50% myometrial invasion, LVSI and lymph node metastasis. Outcomes, however, did not differ between these groups. L1CAM positivity and mutation-type p53 expression were more common in MMRp than in MMRd tumors and did not differ between the MLH1/PMS2 and MSH2/MSH6 loss groups. In the entire cohort, L1CAM and mutation p53 expression were associated with worse prognosis, but only non-endometrioid histology, FIGO stage III/IV, and deep myometrial infiltration were significant predictors. In the subgroup of endometrioid carcinomas, only FIGO stage III/IV was associated with poor outcomes. The risk of lymph node metastasis was associated with tumor size, non-endometrioid histology, and multifocal LVSI. For MMRd tumors, only tumor size and myometrial invasion depth were predictive of lymph node involvement. In our cohort, MMRd tumors were associated with greater recurrence-free, but not overall, survival. The precise identification of MMRd status, present in a substantial proportion of endometrial cancer cases, is a challenge to be overcome for proper patient management. MMRd status serves as a marker for Lynch syndrome, and a significant number of these tumors are high risk and candidate to immunotherapy.

Cancer-specific functional profiling in microsatellite-unstable (MSI) colon and endometrial cancers using combined differentially expressed genes and biclustering analysis

Microsatellite-unstable (MSI) cancers have distinct genetic and clinical features from microsatellite-stable cancers, but the molecular functional differences between MSI cancers originating from different tissues or organs have not been well studied because the application of usual differentially expressed gene (DEG) analysis is error-prone, producing too many noncancer-specific normally functioning genes. To maximize therapeutic efficacy, biomarkers reflecting cancer-specific differences between MSI cancers of different tissue origins should be identified. To identify functional differences between MSI colon and endometrial cancers, we combined DEG analysis and biclustering instead of DEG analysis alone and refined functionally relevant biclusters reflecting genuine functional differences between the 2 tumors. Specifically, using The Cancer Genome Atlas and genome-tissue expression as data sources, gene ontology (GO) enrichment tests were performed after routinely identifying DEGs between the 2 tumors with the exclusion of DEGs identified in their normal counterparts. Cancer-specific biclusters and associated enriched GO terms were obtained by biclustering with enrichment tests for the preferences for cancer type (either colon or endometrium) and GO enrichment tests for each cancer-specific bicluster, respectively. A novel childness score was developed to select functionally relevant biclusters among cancer-specific biclusters based on the extent to which the enriched GO terms of the biclusters tended to be child terms of the enriched GO terms in DEGs. The selected biclusters were tested using survival analysis to validate their clinical significance. We performed multiple sequential analyses to produce functionally relevant biclusters from the RNA sequencing data of MSI colon and endometrial cancer samples and their normal counterparts. We identified 3066 cancer-specific DEGs. Biclustering analysis revealed 153 biclusters and 41 cancer-specific biclusters were selected using Fisher exact test. A mean childness score over 0.6 was applied as the threshold and yielded 8 functionally relevant biclusters from cancer-specific biclusters. Functional differences appear to include gland cavitation and the TGF-β receptor, G protein, and cytokine pathways. In the survival analysis, 6 of the 8 functionally relevant biclusters were statistically significant. By attenuating noise and applying a synergistic contribution of DEG results, we refined candidate biomarkers to complement tissue-specific features of MSI tumors.

The Role of Immunohistochemistry Markers in Endometrial Cancer with Mismatch Repair Deficiency: A Systematic Review

The objective of this systematic review was to summarize our current knowledge of the role of immunohistochemistry (IHC) markers for identifying mismatch repair-deficient (MMRd) tumors in endometrial cancer (EC). Identification of MMRd tumors, which occur in 13% to 30% of all ECs, has become critical for patients with colorectal and endometrial cancer for therapeutic management, clinical decision making, and prognosis. This review was conducted by two authors applying the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using the following terms: “immunohistochemistry and microsatellite instability endometrial cancer” or “immunohistochemistry and mismatch repair endometrial cancer” or “immunohistochemistry and mismatch repair deficient endometrial cancer”. Among 596 retrieved studies, 161 fulfilled the inclusion criteria. Articles were classified and presented according to their interest for the diagnosis, prognosis, and theragnostics for patients with MMRd EC. We identified 10, 18, and 96 articles using IHC expression of two, three, or four proteins of the MMR system (MLH1, MSH2, MHS6, and PMS2), respectively. MLH1 promoter methylation was analyzed in 57 articles. Thirty-four articles classified MMRd tumors with IHC markers according to their prognosis in terms of recurrence-free survival (RFS), overall survival (OS), stage, grade, and lymph node invasion. Theragnostics were studied in eight articles underlying the important concentration of PD-L1 in MMRd EC. Even though the role of IHC has been challenged, it represents the most common, robust, and cheapest method for diagnosing MMRd tumors in EC and is a valuable tool for exploring novel biotherapies and treatment modalities.

miR-486-3p Controls the Apoptosis of Endometrial Carcinoma Cells

Our study aimed to discuss the mechanism of miR-486-3p in controlling the apoptosis of endometrial carcinoma (EC) cells. EC cells were divided into NC group, miR-486-3p mimic and miR-486-3p inhibitor group followed by analysis of miR-486-3p level by Real-time PCR, cell proliferation by spectrophotometric method, apoptosis by FCM, cell migration and invasion by Transwell analysis. EC cells showed reduced miR-486-3p level. The EC malignant biological behaviors could be prompted through retraining miR-486-3p level with increased EC cell invasive capacity. DDR1 was a target of miR-486-3p. The variation of tumor activity could be regulated through controlling DDR1 expression. In conclusion, the apoptotic and invasive characteristic of EC cells are restrained after overexpression of miR-486-3p in EC cells through targeting DDR1, indicating that miR-486-3p could be considered to be one kind of brand-new target for the treatment of EC.