Search results for "MLH1"
showing 10 items of 23 documents
Small Bowel Carcinomas in Coeliac or Crohn’s Disease: Clinico-pathological, Molecular, and Prognostic Features. A Study From the Small Bowel Cancer I…
2017
Background and aims An increased risk of small bowel carcinoma [SBC] has been reported in coeliac disease [CD] and Crohn's disease [CrD]. We explored clinico-pathological, molecular, and prognostic features of CD-associated SBC [CD-SBC] and CrD-associated SBC [CrD-SBC] in comparison with sporadic SBC [spo-SBC]. Methods A total of 76 patients undergoing surgical resection for non-familial SBC [26 CD-SBC, 25 CrD-SBC, 25 spo-SBC] were retrospectively enrolled to investigate patients' survival and histological and molecular features including microsatellite instability [MSI] and KRAS/NRAS, BRAF, PIK3CA, TP53, HER2 gene alterations. Results CD-SBC showed a significantly better sex-, age-, and st…
Somatic mutation profiles as molecular classifiers of ulcerative colitis-associated colorectal cancer.
2021
Ulcerative colitis increases colorectal cancer risk by mechanisms that remain incompletely understood. We approached this question by determining the genetic and epigenetic profiles of colitis-associated colorectal carcinomas (CA-CRC). The findings were compared to Lynch syndrome (LS), a different form of cancer predisposition that shares the importance of immunological factors in tumorigenesis. CA-CRCs (n=27) were investigated for microsatellite instability, CpG island methylator phenotype, and somatic mutations of 999 cancer-relevant genes ("Pan-cancer" panel). A subpanel of "Pan-cancer" design (578 genes) was used for LS colorectal tumors (n=28). Mutational loads and signatures stratifie…
Contribution of Large Genomic Rearrangements in Italian Lynch Syndrome Patients: Characterization of a Novel Alu-Mediated Deletion
2012
Lynch syndrome is associated with germ-line mutations in the DNA mismatch repair (MMR) genes, mainlyMLH1andMSH2. Most of the mutations reported in these genes to date are point mutations, small deletions, and insertions. Large genomic rearrangements in the MMR genes predisposing to Lynch syndrome also occur, but the frequency varies depending on the population studied on average from 5 to 20%. The aim of this study was to examine the contribution of large rearrangements in theMLH1andMSH2genes in a well-characterised series of 63 unrelated Southern Italian Lynch syndrome patients who were negative for pathogenic point mutations in theMLH1,MSH2, andMSH6genes. We identified a large novel delet…
Expression of selected molecular factors in two types of endometrial cancer
2021
BACKGROUND Endometrial cancers (EC) are a heterogeneous group of malignant neoplasms differing in etiology, clinical-pathological features and prognosis. OBJECTIVES To determine the differences between the expression of selected molecular factors and find connections between them in order to isolate possible biomarkers influencing treatment options. MATERIAL AND METHODS The investigated data involved archival histological preparations obtained from uterine EC samples taken from 137 patients, treated surgically between 2007 and 2014. The immunohistochemical Dako EnVisionTM Flex+ method was applied. RESULTS The expression of ERβ, MLH1 and BRCA1 was lower in ECI than in ECII patients. The ERα …
In the literature: October 2018
2018
Several trials with the check-point inhibitors pembrolizumab or nivolumab demonstrated some antitumour efficacy in chemorefractory advanced gastric cancer with a response rate ranging from 10% to 26%. However, no clear predictive biomarkers were found to facilitate a proper selection of patients. A series of 61 patients with advanced gastric cancer received second-line or third-line treatment with pembrolizumab in a prospective phase 2 trial.1 In a cooperative effort carried out by Korean and American investigators, a molecular characterisation of all tumours was performed including whole-exome sequencing and RNA sequencing of tissue biopsies, as well as circulating tumour DNA (ctDNA) from …
Correction:Cancer risks by gene, age, and gender in 6350 carriers of pathogenic mismatch repair variants: findings from the Prospective Lynch Syndrom…
2020
Lynch syndrome (LS) results from pathogenic variants in the mismatch repair (MMR) genes and is the most common hereditary cancer syndrome, affecting an estimated 1 in 300 individuals. Pathogenic variants in each of the MMR genes path_MLH1, path_MSH2, path_MSH6, and path_PMS2 result in different risks for cancers in organs including the colorectum, endometrium, ovaries, stomach, small bowel, bile duct, pancreas, and upper urinary tract. Accurate estimates of these risks are essential for planning appropriate approaches to the prevention or early diagnosis of cancers but the robustness of previous studies has been limited by factors including retrospective design,1,2 lack of validation in ind…
Hereditary ovarian cancer.
2008
Apoptosis is a form of cell death that permits the removal of damaged, senescent or unwanted cells in multicellular organisms, without damage to the cellular microenvironment. Defective apoptosis represents a major causative factor in the development and progression of cancer. The majority of chemotherapeutic agents, as well as radiation, utilize the apoptotic pathway to induce cancer cell death. Resistance to standard chemotherapeutic strategies also seems to be due to alterations in the apoptotic pathway of cancer cells. Recent knowledge on apoptosis has provided the basis for novel targeted therapies that exploit apoptosis to treat cancer. These new target include those acting in the ext…
No Difference in Penetrance between Truncating and Missense/Aberrant Splicing Pathogenic Variants in MLH1 and MSH2: A Prospective Lynch Syndrome Data…
2021
Background. Lynch syndrome is the most common genetic predisposition for hereditary cancer. Carriers of pathogenic changes in mismatch repair (MMR) genes have an increased risk of developing colorectal (CRC), endometrial, ovarian, urinary tract, prostate, and other cancers, depending on which gene is malfunctioning. In Lynch syndrome, differences in cancer incidence (penetrance) according to the gene involved have led to the stratification of cancer surveillance. By contrast, any differences in penetrance determined by the type of pathogenic variant remain unknown. Objective. To determine cumulative incidences of cancer in carriers of truncating and missense or aberrant splicing pathogenic …
In the literature: April 2020
2020
Deficient DNA mismatch repair (dMMR) may be caused by germline or somatic mutations in mismatch repair genes ( MLH1 , MSH2 , MSH3 , MSH6 and PMS2 ) or through epigenetic silencing of MLH1 .1 dMMR induces a hypermutator phenotype, also known as microsatellite instability (MSI). Next-generation sequencing identifies MSI in 12 cancer types. The highest prevalence is seen in endometrial cancer (31.4%), followed by colorectal cancer (19.7%) and gastric cancer (GC, 19.1%). MSI was related to better prognosis for colorectal cancer and GC . Moreover, the dMMR/MSI hypermutator phenotype is thought to produce large numbers of immunogenic neoantigens that can be recognised by immune cells, leading to …
Expression of hMLH1 and hMSH2 proteins in ameloblastomas and tooth germs
2017
Background Mismatch repair proteins (MMRPs) are a group of nuclear enzymes that participate in the repair of base mismatches that occur during DNA replication in all proliferating cells. The most studied MMRPs are hMSH2 and hMLH1, which are known to be highly expressed in normal tissues. A loss of MMRPs leads to the accumulation of DNA replication errors in proliferating cells. Ki-67 is a biomarker regarded to be the gold-standard tool for determining cell proliferation by immunohistochemical methods. The aim of this study was to investigate the immunohistochemical expression of hMLH1, hMSH2 and Ki-67 proteins in ameloblastomas and tooth germs, to contribute to the understanding of the deve…