Search Results (48)

Background: Mismatch repair deficiency (MMRd) is a central molecular determinant of colorectal cancer (CRC) biology, prognosis, and treatment response, and Universal Tumour Screening (UTS) is advocated for Lynch syndrome (LS) detection; yet real-world performance across clinical subgroups remains limited. We evaluated MMRd distribution and UTS-based LS detection in a large consecutive surgical cohort. Methods: We retrospectively analyzed 1022 consecutive CRC patients undergoing surgical resection at the University Hospital of Padua (2015–2023). MMR status was assessed by immunohistochemistry; MMRd cases underwent reflex BRAF mutation testing and, when available, MLH1 promoter methylation analysis, followed by germline multigene panel testing for suspected LS. Clinicopathological features were compared by MMR status, age at onset, and tumour location. Results: MMR testing was performed in 875 patients (85.6%), rising from 67.0% (2015–2017) to 97.4% (2021–2023). MMRd was identified in 139 tumors (15.9%) and was independently associated with age ≥ 70 years, colonic location, and stage 0–II. Of 22 patients with confirmed LS, 13 (59.1%) were newly identified through UTS; family history showed no significant univariate association with LS status and was not independently associated with MMRd after multivariable adjustment. MMRd prevalence was numerically higher in early- than late-onset CRC (20.0% vs. 15.4%), approaching significance after multivariable adjustment (OR 1.90, 95% CI 0.99–3.64; p = 0.054); hereditary syndromes were also more frequent in early-onset disease. MMRd was markedly rarer in rectal than colonic cancer (4.1% vs. 22.5%; p < 0.0001), though MMRd rectal cancers arose in younger patients. Conclusions: UTS identified a substantial proportion of LS carriers missed by age- or family-history criteria. The relationship between age and MMRd prevalence proved more nuanced than a simple comparison would suggest, reinforcing the value of universal over selective testing across the age spectrum, while MMRd rectal cancer shows a distinct younger profile relevant to immunotherapy-based organ preservation. Full article

Endometrial cancer (EC) is increasingly recognized as a heterogeneous disease, yet current treatment strategies often fail to explain why tumors with similar molecular profiles respond differently or develop resistance. This gap points to regulatory mechanisms beyond static genomic alterations. Epigenetic dysregulation through DNA methylation, histone modification, and non-coding RNA (ncRNAs) networks acts as a dynamic and reversible system that governs how tumors adapt under therapeutic pressure. In EC, alterations affecting key regulators such as MLH1, PTEN, and hormone receptors directly influence sensitivity to immunotherapy, targeted therapy, and endocrine treatment, defining treatment-responsive and treatment-resistant states. These observations shift the role of epigenetics from a descriptive feature of tumor biology to a determinant of therapeutic behaviour. Epigenetic states influence immune recognition, pathway activation, and cell cycle control, thereby shaping response to chemotherapy and immune checkpoint blockade. Biomarkers derived from these alterations, including methylation signatures and circulating RNAs, offer opportunities for patient stratification and longitudinal monitoring of treatment response. Therapeutically, targeting epigenetic regulators provides a strategy to reverse resistance and restore treatment sensitivity. DNA methyltransferase and histone deacetylase inhibitors, particularly in combination with established therapies, have shown potential to enhance treatment efficacy. Emerging approaches, including locus-specific epigenetic editing and liquid biopsy–guided monitoring, further support adaptive treatment strategies. Integrating epigenetic reprogramming into clinical decision-making offers a practical path toward improving treatment response and overcoming resistance in EC. Here, we propose an Epigenetic State–Response Framework (ESRF) in which dynamic epigenetic states define treatment-sensitive and resistant phenotypes, map to specific therapeutic vulnerabilities, and can be actively reprogrammed to restore treatment response. Full article

The escalating incidence of colorectal cancer (CRC), particularly the alarming rise in early-onset cases, necessitates a paradigm shift from a purely genetic perspective to a broader investigation of promising pathways. This review explores the “nutri-epigenetic” interface, positioning liquid biopsy as a critical technology for translating dietary impacts into actionable clinical biomarkers. We contrast the molecular consequences of the Western dietary pattern, characterized by methyl-donor deficiency and pro-inflammatory metabolites, with the protective mechanisms of the Mediterranean diet. Mechanistically, we detail how Western-style diets drive a specific “epigenetic double-hit”: promoting global DNA hypomethylation (destabilizing LINE-1) while paradoxically inducing promoter hypermethylation of critical tumour suppressors (MLH1, APC, MGMT) and silencing tumour-suppressive microRNAs (miR-34b/c, miR-137) via methylation of their encoding genes. Conversely, we highlight the capacity of Mediterranean bioactive compounds (e.g., resveratrol, curcumin, butyrate) to inhibit DNA methyltransferases and restore epigenetic homeostasis. Bridging molecular biology and clinical utility, we demonstrate how these diet-sensitive signatures, specifically circulating methylated DNA and dysregulated microRNAs, can be captured via liquid biopsy. We propose that these circulating analytes serve as dynamic, accessible biomarkers for monitoring the molecular progression toward a carcinogenic state, thereby establishing a novel framework for personalized risk stratification and validating the efficacy of preventive nutritional strategies. Full article

Background: Endometrial hyperplasia (EH) represents a precursor lesion in the development of endometrial carcinoma, particularly the endometrioid subtype. Among the molecular pathways involved, microsatellite instability (MSI) resulting from DNA mismatch repair (MMR) deficiency has gained increasing attention as an early event in endometrial carcinogenesis. Objective: This study aimed to evaluate the expression of key MMR proteins (MLH1, PMS2, MSH2, and MSH6) in endometrial hyperplasia without atypia and endometrial atypical hyperplasia/endometrioid intraepithelial neoplasia (EAH/EIN) to determine the prevalence and potential implications of MMR deficiency at the precancerous stage. Methods: Fifty-six cases of EH were analyzed, including 28 endometrial hyperplasia without atypia and 28 EAH/EIN. Immunohistochemical (IHC) analysis was performed to assess the nuclear expression of MMR proteins. Loss of expression was defined as complete absence of epithelial nuclear staining with retained stromal positivity. Results: MMR protein expression was retained in all cases of endometrial hyperplasia without atypia, while total loss of one or more MMR proteins was observed in 3 of 28 (10.7%) EAH/EIN. The most frequent pattern involved concurrent MLH1/PMS2 loss, consistent with sporadic MLH1 promoter hypermethylation. One case exhibited isolated MSH6 loss, suggesting a potential Lynch syndrome, and another showed combined MSH6/PMS2 loss. Conclusions: MMR deficiency appears confined to atypical EH, supporting its role as an early molecular alteration in the neoplastic sequence leading to endometrioid carcinoma. Identification of abnormal MMR expression in EH may facilitate risk stratification, guide reflex testing for MLH1 methylation, and prompt genetic counseling for hereditary cancer predisposition. Full article

Endometrial cancer (EC) is the most common gynecological malignancy in developed countries. Risk factors for EC include metabolic alterations (obesity, metabolic syndrome, insulin resistance), hormonal imbalance, age at menopause, reproductive factors, and inherited conditions, such as Lynch syndrome. For the inherited forms, several genes had been implicated in EC occurrence and development, such as POLE, MLH1, TP53, PTEN, PIK3CA, PIK3R1, CTNNB1, ARID1A, PPP2R1A, and FBXW7, all mutated at high frequency in EC patients. However, gene function impairment is not necessarily caused by mutations in the coding sequence of these and other genes. Gene function alteration may also occur through post-transcriptional control of messenger RNA translation, frequently caused by microRNA action, but transcriptional impairment also has a profound impact. Here, we review how chromatin modifications change the expression of genes whose impaired function is directly related to EC etiopathogenesis. Chromatin modification plays a central role in EC. The modification of chromatin structure alters the accessibility of genes to transcription factors and other regulatory proteins, thus altering the intracellular protein amount. Thus, DNA structural alterations may impair gene function as profoundly as mutations in the coding sequences. Hence, its central importance is in the diagnostic and prognostic evaluation of EC patients, with the caveat that chromatin alteration is often difficult to identify and needs investigations that are specific and not broadly used in common clinical practice. The different phases of the healthy endometrium menstrual cycle are characterized by differential gene expression, which, in turn, is also regulated through epigenetic mechanisms involving DNA methylation, histone post-translational modifications, and non-coding RNA action. From a medicolegal and policy-making perspective, the implications of using epigenetics in cancer care are briefly explored as well. Epigenetics in endometrial cancer is not only a topic of biomedical interest but also a crossroads between science, ethics, law, and public health, requiring integrated approaches and careful regulation. Full article

DNA methylation of tumor suppressor genes in cancer is known to be a mechanism for silencing gene expression, but much remains unknown about its extent and relationship to somatic variants at the DNA sequence level. In this study, we comprehensively analyzed DNA methylation and somatic variants of all gene regions across the genome of the major tumor suppressor genes, APC, TP53, SMAD4, and mismatch repair genes in colorectal cancer using a novel next-generation sequencing-based analysis method. The Targeted Methyl Landscape (TML) shows that DNA hypermethylation patterns of these tumor suppressor genes in colorectal cancer are more complex and widespread than previously thought. Extremely high levels of DNA methylation were observed in relatively long regions around exon 1A of APC and exon 1 and surrounding region of MLH1. DNA hypermethylation occurred whether or not somatic DNA variants were present in the tumor. Even in tumors where the loss of heterozygosity has been demonstrated by somatic variants alone, additional methylation of the same gene can occur. Our data demonstrate that somatic variants and hypermethylation of these tumor suppressor genes were considered independent, parallel events, not exclusive of each other or having one event affecting the other. Full article

Background/Objectives: The purpose of the current study was to compare the methylation of five regions of the CpG island of MLH1 with the presence of microsatellite instability (MSI) in colorectal cancer (CRC) patients. Methods: The study analyzed 138 CRC tumor samples. DNA extraction was performed, followed by bisulfite conversion. MLH1 gene methylation was assessed by methylation-specific PCR (MS-PCR), and the resulting fragments were analyzed using polyacrylamide gels. MSI was evaluated using multiplex PCR, and the fragments were run through capillary electrophoresis. R studio (v4.4.1) and SPSS (v29.0) software were used for the statistical analysis, and values of p < 0.05 were considered statistically significant. Results: The study showed 75.4% unmethylated, 21% partially methylated, and 3.6% fully methylated samples, with region A frequently methylated. MSI was observed in 7.2% of cases (MSI-H: 5.8%, MSI-L: 1.4%). BAT-26 was the most unstable marker. A significant difference between MLH1 methylation and MSI-H (p < 0.01) was identified, but there was no relationship with specific MLH1 regions. Conclusions: No differences were identified when analyzing specific methylation regions in relation to MSI. This study is the first to describe MSI frequency in Mexican patients regardless of age. Full article

Enzymes capable of processing a variety of compounds enable plants to adapt to diverse environmental conditions. PRISEs (progesterone-5β-reductase/iridoid synthase-like enzymes), examples of such substrate-promiscuous enzymes, are involved in iridoid and cardenolide pathways and demonstrate notable substrate promiscuity by reducing the activated C=C double bonds of plant-borne and exogenous 1,4-enones. In this study, we identified PRISE genes in Plantago media (PmdP5βR1) and Plantago lanceolata (PlP5βR1), and the corresponding enzymes were determined to share a sequence identity of 95%. Despite the high sequence identity, recombinant expressed PmdP5βR1 was 70 times more efficient than PlP5βR1 for converting progesterone. In order to investigate the underlying reasons for this significant discrepancy, we focused on specific residues located near the substrate-binding pocket and adjacent to the conserved phenylalanine “clamp”. This clamp describes two phenylalanines influencing substrate preferences by facilitating the binding of smaller substrates, such as 2-cyclohexen-1-one, while hindering larger ones, such as progesterone. Using structural analysis based on templates PDB ID: 5MLH and 6GSD from PRISE of Plantago major, along with in silico docking, we identified positions 156 and 346 as hot spots. In PlP5βR1 amino acid residues, A156 and F346 seem to be responsible for the diminished ability to reduce progesterone. Moreover, the double mutant PlP5βR_F156L_A346L, which contains the corresponding amino acids from PmdP5βR1, showed a 15-fold increase in progesterone 5β-reduction. Notably, this modification did not significantly alter the enzyme’s ability to convert other substrates, such as 8-oxogeranial, 2-cyclohexen-1-one, and methyl vinyl ketone. Hence, a rational enzyme design by reducing the number of hotspots selectively, specifically improved the substrate preference of PlP5βR1 for progesterone. Full article

Introduction. The treatment for patients with high-grade gliomas includes surgical resection of tumor, radiotherapy, and temozolomide chemotherapy. However, some patients do not respond to temozolomide due to a methylation reversal mechanism by the enzyme O⁶-methylguanine-DNA-methyltransferase (MGMT). In patients receiving treatment with temozolomide, this biomarker has been used as a prognostic factor. However, not all patients respond in the same way, which suggests the existence of other proteins involved in resistance to temozolomide chemotherapy. Methods. A group of thirty-one patients was recruited who were clinically and pathologically diagnosed with high-grade gliomas. The sequencing of 324 genes related to different types of cancer was performed to detect mutations. Subsequently, a statistical analysis was conducted to determine the mutated genes that were most related to resistance to treatment. Results. According to the Stupp protocol and metronomic dose of the temozolomide treatment, the mutated genes related to the second relapse of patients with high-grade glioma were PIK3C2B, KIT, ERBB3, and MLH1. Conclusions. Considering the results obtained, we suggest that mutations in the four genes and methylation of the gene promoter that codes for the MGMT protein could be related to response to treatment with temozolomide. Full article

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. Full article

Methyl gallate (MG) and gallic acid (GA) are natural compounds with potent activity against methicillin-resistant Staphylococcus aureus (MRSA), a significant global health concern. In this study, MG and GA were incorporated into cellulose acetate (CA) blended with poly(vinyl alcohol) (PVA) to create electrospun nanofibers aimed at combating both methicillin-susceptible S. aureus (MSSA) and MRSA. Key electrospinning parameters—DC voltage, injection flow rate, and syringe tip–collector distance—were optimized, with the best conditions being a 1.5 mL/h flow rate, 30 cm distance, and 20 kV voltage. The resulting nanofiber mats were characterized by SEM, FTIR, DSC, tensile strength testing, contact angle measurement, swelling behavior, and release profiling. Antibacterial properties were assessed using the agar diffusion test. The obtained nanofibers had diameters ranging from 879.33 to 906.13 nm. Among the samples, MG-GA-CA/PVA exhibited the highest tensile strength, good flexibility, and improved stiffness, which was related to enhanced thermal stability and chemical interactions as shown by DSC and FTIR analyses. This formulation also displayed excellent hydrophilicity, swelling properties, and a consistent release profile over 8 to 24 h. Furthermore, MG-GA-CA/PVA showed superior antibacterial activity against both MSSA and MRSA, suggesting its potential as a strong, flexible, and effective anti-S. aureus material. Full article

Background: In cancer care, the MLH1 gene is crucial for DNA mismatch repair (MMR), serving as a vital tumor suppressor. Evaluating MLH1 protein expression status, followed by analysis of MLH1 promoter methylation, has become a key diagnostic and prognostic approach. Our study investigates the complex link between MLH1 methylation and prognosis in endometrial adenocarcinoma (EA) patients. Methodology: MLH1 methylation status was accessed by a Pyrosequencing (PSQ) assay. Qualitative positivity for methylation was established if it exceeded the 11% cut-off; as well, a quantitative methylation analysis was conducted to establish correlations with clinicopathological data, relapse-free survival, and disease-free survival. Results: Our study revealed that 33.3% of patients without MLH1 methylation experienced relapses, surpassing the 23.3% in patients with methylation. Furthermore, 16.7% of patients without methylation succumbed to death, with a slightly higher rate of 17.6% in methylated patients. Qualitative comparisons highlighted that the mean methylation rate in patients experiencing relapse was 35.8%, whereas in those without relapse, it was 42.2%. This pattern persisted in disease-specific survival (DSS), where deceased patients exhibited a higher mean methylation level of 49.1% compared to living patients with 38.8%. Conclusions: Our findings emphasize the efficacy of PSQ for evaluating MLH1 methylation. While unmethylation appears to be associated with a higher relapse rate, the survival rate does not seem to be influenced by methylation. Quantitative percentages suggest that elevated MLH1 methylation is linked to relapse and mortality, though a study with a larger sample size would be essential for statistically significant results. Full article

Uterine corpus endometrial carcinoma (UCEC) poses significant clinical challenges due to its high incidence and poor prognosis, exacerbated by the lack of effective screening methods. The standard treatment for UCEC typically involves surgical intervention, with radiation and chemotherapy as potential adjuvant therapies. In recent years, immunotherapy has emerged as a promising avenue for the advanced treatment of UCEC. This study employs a multi-omics approach, analyzing RNA-sequencing data and clinical information from The Cancer Genome Atlas (TCGA), Gene Expression Profiling Interactive Analysis (GEPIA), and GeneMANIA databases to investigate the prognostic value of MutL Homolog 1 (MLH1) gene expression in UCEC. The dysregulation of MLH1 in UCEC is linked to adverse prognostic outcomes and suppressed immune cell infiltration. Gene Set Enrichment Analysis (GSEA) data reveal MLH1’s involvement in immune-related processes, while its expression correlates with tumor mutational burden (TMB) and microsatellite instability (MSI). Lower MLH1 expression is associated with poorer prognosis, reduced responsiveness to Programmed cell death protein 1 (PD-1)/Programmed death-ligand 1 (PD-L1) inhibitors, and heightened sensitivity to anti-cancer agents. This comprehensive analysis establishes MLH1 as a potential biomarker for predicting prognosis, immunotherapy response, and drug sensitivity in UCEC, offering crucial insights for the clinical management of patients. Full article

(1) Background: MLH1 hypermethylation is an epigenetic alteration in the tumorigenesis of colorectal cancer (CRC) and endometrial cancer (EC), causing gene silencing, and, as a consequence, microsatellite instability. Commonly, MLH1 hypermethylation is considered a somatic and sporadic event in cancer, and its detection is recognized as a useful tool to distinguish sporadic from inherited conditions (such as, Lynch syndrome (LS)). However, MLH1 hypermethylation has been described in rare cases of CRC and EC in LS patients. (2) Methods: A total of 61 cancers (31 CRCs, 27 ECs, 2 ovarian cancers, and 1 stomach cancer) from 56 patients referred to cancer genetic counselling were selected for loss of MLH1 protein expression and microsatellite instability. All cases were investigated for MLH1 promoter methylation and MLH1/PMS2 germline variants. (3) Results: Somatic MLH1 promoter hypermethylation was identified in 16.7% of CRC and in 40% of EC carriers of MLH1 germline pathogenic variants. In two families, primary and secondary MLH1 epimutations were demonstrated. (4) Conclusions: MLH1 hypermethylation should not be exclusively considered as a sporadic cancer mechanism, as a non-negligible number of LS-related cancers are MLH1 hypermethylated. Current flow charts for universal LS screening, which include MLH1 methylation, should be applied, paying attention to a patient’s family and personal history. Full article

MLH1/PMS2 loss due to MLH1 promoter hypermethylation (MLH1-PHM) is the most common cause of mismatch repair (MMR) deficiency in endometrial cancer (EC). This study aimed to determine the proportion of MLH1-deficient EC with PHM, assess the impact of the reflex MLH1-PHM testing strategy, and evaluate the associated costs within the publicly funded Canadian healthcare system. In a cohort of 2504 EC samples, 534 (21.4%) exhibited dual MLH1/PMS2 loss, prompting MLH1-PHM testing. Among 418 cases with available testing results, 404 (96.7%) were MLH1-hypermethylated, while 14 (3.3%) were non-methylated. The incidence of MLH1 non-methylated cases in our cohort was 14/2504 (0.56%) of all ECs, underscoring the prevalence of hypermethylation-driven MLH1/PMS2 loss in ECs universally screened for MMR deficiency. Reflex MLH1-PHM testing incurs substantial costs and resource utilization. Assay cost is CAD 231.90 per case, amounting to CAD 123,834.60 for 534 cases, with 30 tests needed per additional candidate for MLH1 germline analysis (CAD 6957.00 per candidate). This raises a provocative question: can we assume that the majority of the MLH1-deficient ECs are due to PHM and forgo further testing in healthcare systems with finite resources? It is imperative to assess resource utilization efficiency and explore optimized approaches that encompass clinical correlation, family history and judicious utilization of methylation testing to ensure it is provided only to those who stand to benefit from it. Full article