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MLH1 hypermethylation

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https://www.readbyqxmd.com/read/28344746/cpg-island-methylator-phenotype-in-adenocarcinomas-from-the-digestive-tract-methods-conclusions-and-controversies
#1
EDITORIAL
Francisco Sánchez-Vega, Valer Gotea, Yun-Ching Chen, Laura Elnitski
Over the last two decades, cancer-related alterations in DNA methylation that regulate transcription have been reported for a variety of tumors of the gastrointestinal tract. Due to its relevance for translational research, great emphasis has been placed on the analysis and molecular characterization of the CpG island methylator phenotype (CIMP), defined as widespread hypermethylation of CpG islands in clinically distinct subsets of cancer patients. Here, we present an overview of previous work in this field and also explore some open questions using cross-platform data for esophageal, gastric, and colorectal adenocarcinomas from The Cancer Genome Atlas...
March 15, 2017: World Journal of Gastrointestinal Oncology
https://www.readbyqxmd.com/read/28304185/modulation-of-transcription-factor-binding-and-epigenetic-regulation-of-the-mlh1-cpg-island-and-shore-by-polymorphism-rs1800734-in-colorectal-cancer
#2
Andrea J Savio, Bharati Bapat
The MLH1 promoter polymorphism rs1800734 is associated with MLH1 CpG island hypermethylation and expression loss in colorectal cancer (CRC). Conversely, variant rs1800734 is associated with MLH1 shore, but not island, hypomethylation in peripheral blood mononuclear cell DNA. To explore these distinct patterns, MLH1 CpG island and shore methylation was assessed in CRC cell lines stratified by rs1800734 genotype. Cell lines containing the variant A allele demonstrated MLH1 shore hypomethylation compared to wild type (GG)...
March 17, 2017: Epigenetics: Official Journal of the DNA Methylation Society
https://www.readbyqxmd.com/read/28293327/the-dynamic-dna-methylation-landscape-of-the-mutl-homolog-1-shore-is-altered-by-mlh1-93g-a-polymorphism-in-normal-tissues-and-colorectal-cancer
#3
Andrea J Savio, Miralem Mrkonjic, Mathieu Lemire, Steven Gallinger, Julia A Knight, Bharat Bapat
BACKGROUND: Colorectal cancers (CRCs) undergo distinct genetic and epigenetic alterations. Expression of mutL homolog 1 (MLH1), a mismatch repair gene that corrects DNA replication errors, is lost in up to 15% of sporadic tumours due to mutation or, more commonly, due to DNA methylation of its promoter CpG island. A single nucleotide polymorphism (SNP) in the CpG island of MLH1 (MLH1-93G>A or rs1800734) is associated with CpG island hypermethylation and decreased MLH1 expression in CRC tumours...
2017: Clinical Epigenetics
https://www.readbyqxmd.com/read/28258479/prevalence-and-clinicopathologic-molecular-characteristics-of-mismatch-repair-deficient-colorectal-cancer-in-the-under-50-year-old-japanese-population
#4
Okihide Suzuki, Hidetaka Eguchi, Noriyasu Chika, Takehiko Sakimoto, Keiichiro Ishibashi, Kensuke Kumamoto, Jun-Ichi Tamaru, Tetsuhiko Tachikawa, Kiwamu Akagi, Tomio Arai, Yasushi Okazaki, Hideyuki Ishida
PURPOSE: To clarify the prevalence and clinicopathologic/molecular characteristics of mismatch repair (MMR)-deficient colorectal cancer in the young Japanese population. METHODS: Immunohistochemical analyses for MMR proteins (MLH1, MSH2, MSH6, and PMS2) were performed in formalin-fixed paraffin-embedded sections prepared from the resected CRC specimens of 119 consecutive patients aged <50 years old, who underwent resection of the primary tumor at our institution between 1996 and 2015...
March 3, 2017: Surgery Today
https://www.readbyqxmd.com/read/28224663/loss-of-mlh1-sensitizes-colon-cancer-cells-to-dna-pkcs-inhibitor-ku60648
#5
Inga Hinrichsen, Anne Ackermann, Tonja Düding, Annika Graband, Natalie Filmann, Guido Plotz, Stefan Zeuzem, Angela Brieger
Germline mutations of MLH1 are responsible for tumor generation in nearly 50% of patients with Lynch Syndrome, and around 15% of sporadic colorectal cancers show MLH1-deficiency due to promotor hypermethylation. Although these tumors are of lower aggressiveness the benefit for these patients from standard chemotherapy is still under discussion. Recently, it was shown that the sensitivity to the DNA-PKcs inhibitor KU60648 is linked to loss of the MMR protein MSH3. However, loss of MSH3 is rather secondary, as a consequence of MMR-deficiency, and frequently detectable in MLH1-deficient tumors...
February 22, 2017: Molecular Carcinogenesis
https://www.readbyqxmd.com/read/27984238/pd-l1-expression-in-mismatch-repair-deficient-endometrial-carcinomas-including-lynch-syndrome-associated-and-mlh1-promoter-hypermethylated-tumors
#6
Emily A Sloan, Kari L Ring, Brian C Willis, Susan C Modesitt, Anne M Mills
Mismatch repair (MMR)-deficient endometrial carcinomas (ECs) bearing Lynch syndrome (LS)-associated germline mutations or sporadic MLH1 promoter hypermethylation (MLH1hm) are highly immunogenic and may represent excellent candidates for therapies targeting the programmed cell death (PD)/programmed cell death ligand-1 (PD-L1) immune checkpoint pathway. This study evaluates PD-L1 expression in MMR-deficient ECs including LS-associated and MLH1hm cases, in comparison with MMR-intact tumors. Immunohistochemistry for PD-L1/CD274 was performed on 38 MMR-deficient and 29 MMR-intact ECs...
March 2017: American Journal of Surgical Pathology
https://www.readbyqxmd.com/read/27920101/prevalence-of-lynch-syndrome-and-lynch-like-syndrome-among-patients-with-colorectal-cancer-in-a-japanese-hospital-based-population
#7
Noriyasu Chika, Hidetaka Eguchi, Kensuke Kumamoto, Okihide Suzuki, Keiichiro Ishibashi, Tetsuhiko Tachikawa, Kiwamu Akagi, Jun-Ichi Tamaru, Yasushi Okazaki, Hideyuki Ishida
Objective: We investigated the prevalence of Lynch syndrome and Lynch-like syndrome among Japanese colorectal cancer patients, as there have been no credible data from Japan. Methods: Immunohistochemical analyses for mismatch repair proteins (MLH1, MSH2, MSH6 and PMS2) were carried out in surgically resected, formalin-fixed paraffin-embedded specimens obtained from 1,234 newly diagnosed colorectal cancer patients between March 2005 and April 2014. The presence/absence of the BRAF V600E mutation and hypermethylation of the MLH1 promoter was analyzed where necessary...
February 9, 2017: Japanese Journal of Clinical Oncology
https://www.readbyqxmd.com/read/27896617/comprehensive-dna-methylation-and-mutation-analyses-reveal-a-methylation-signature-in-colorectal-sessile-serrated-adenomas
#8
Árpád V Patai, Barbara Kinga Barták, Bálint Péterfia, Tamás Micsik, Réka Horváth, Csaba Sumánszki, Zoltán Péter, Árpád Patai, Gábor Valcz, Alexandra Kalmár, Kinga Tóth, Tibor Krenács, Zsolt Tulassay, Béla Molnár
Colorectal sessile serrated adenomas (SSA) are hypothesized to be precursor lesions of an alternative, serrated pathway of colorectal cancer, abundant in genes with aberrant promoter DNA hypermethylation. In our present pilot study, we explored DNA methylation profiles and examined selected gene mutations in SSA. Biopsy samples from patients undergoing screening colonoscopy were obtained during endoscopic examination. After DNA isolation and quality analysis, SSAs (n = 4) and healthy controls (n = 5) were chosen for further analysis...
November 29, 2016: Pathology Oncology Research: POR
https://www.readbyqxmd.com/read/27789085/cost-effectiveness-of-routine-screening-for-lynch-syndrome-in-endometrial-cancer-patients-up-to-70years-of-age
#9
Anne Goverde, Manon Cw Spaander, Helena C van Doorn, Hendrikus J Dubbink, Ans Mw van den Ouweland, Carli M Tops, Sjarlot G Kooi, Judith de Waard, Robert F Hoedemaeker, Marco J Bruno, Robert Mw Hofstra, Esther W de Bekker-Grob, Winand Nm Dinjens, Ewout W Steyerberg, Anja Wagner
PURPOSE: To assess cost-effectiveness of routine screening for Lynch Syndrome (LS) in endometrial cancer (EC) patients ≤70years of age. METHODS: Consecutive EC patients ≤70years of age were screened for LS by analysis of microsatellite instability, immunohistochemistry and MLH1 hypermethylation. Costs and health benefit in life years gained (LYG) included surveillance for LS carriers among EC patients and relatives. We calculated incremental cost-effectiveness ratios (ICERs) comparing LS screening among EC patients ≤70years with ≤50years and the revised Bethesda guidelines...
December 2016: Gynecologic Oncology
https://www.readbyqxmd.com/read/27742654/practical-guidance-for-mismatch-repair-deficiency-testing-in-endometrial-cancer
#10
E Stelloo, A M L Jansen, E M Osse, R A Nout, C L Creutzberg, D Ruano, D N Church, H Morreau, V T H B M Smit, T van Wezel, T Bosse
Background: Mismatch repair (MMR)-deficiency analysis is increasingly recommended for all endometrial cancers, as it identifies Lynch syndrome patients, and is emerging as a prognostic classifier to guide adjuvant treatment. The aim of this study was to define the optimal approach for MMR-deficiency testing and to clarify discrepancies between microsatellite instability (MSI) analysis and immunohistochemical (IHC) analysis of MMR protein expression. Patients and methods: Six hundred ninety- six endometrial cancers were analyzed for MSI (pentaplex panel) and MMR protein expression (IHC)...
January 1, 2017: Annals of Oncology: Official Journal of the European Society for Medical Oncology
https://www.readbyqxmd.com/read/27638535/-pathogenetic-aspects-in-precursor-lesions-of-gastrointestinal-tumors
#11
T Rau
The pathogenesis of precursor lesions of gastrointestinal tumors is manifested in many ways. In the esophagus an aberrant genetic expression of intestinal transcription factors, such as CDX2 is initiated by local environment factors. During the subsequent dysplasia to carcinoma sequence, chromosomal gain and loss of genes occurs. A 4-color fluorescence in situ hybridization (FISH) assay can be applied in dysplasia as well as in Barrett's adenocarcinoma to define prognostic marker combinations. In the gastric carcinogenesis sequence the gene expression of CDX1 is regulatively dependent on an interplay between inflammation and promotor methylation...
November 2016: Der Pathologe
https://www.readbyqxmd.com/read/27544395/evaluation-of-a-subset-of-tumor-suppressor-gene-for-copy-number-and-epigenitic-changes-in-pleomorphic-adenoma-and-carcinoma-ex-pleomorphic-adenoma-carcinogenesis
#12
Fernanda Viviane Mariano, Erika Said Egal, Dimitrius Pramio, Felipe Fidalgo, Érica Sara, Ana Flávia Costa, Rogério de Oliveira Gondak, Ricardo Della Coletta, Oslei Paes de Almeida, Luiz Paulo Kowalski, Ana Cristina Victorino Krepischi, Albina Altemani
OBJECTIVE: The progression of pleomorphic adenoma (PA) to carcinoma ex-pleomorphic adenoma (CXPA) encompasses several genomic alterations involving complex pathways. Tumor suppressor genes seem to play important roles in the tumorigenesis of both tumors. The aim of this study was to evaluate copy number and methylation of tumor suppressor genes' status in PA and CXPA samples. STUDY DESIGN: Eight cases of PA, 2 cases of residual PA in CXPA, and 5 cases of CXPA were studied; the latter were classified according to invasiveness and histopathological subtype...
September 2016: Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
https://www.readbyqxmd.com/read/27513077/mucinous-differentiation-with-tumor-infiltrating-lymphocytes-is-a-feature-of-sporadically-methylated-endometrial-carcinomas
#13
Emily A Sloan, Christopher A Moskaluk, Anne M Mills
Defects in the DNA mismatch-repair system are identified in ∼25%-30% of endometrial carcinomas (ECs). Whereas some ECs are due to germline Lynch syndrome (LS)-associated mutations, the majority demonstrate sporadic MLH1 promoter hypermethylation (MLH1hm). MLH1hm characterizes a unique subset of colorectal cancers with a relatively poor prognosis; however, the morphology and behavior of sporadically methylated ECs (SMECs) are less well understood. We herein review the clinicopathologic features of 34 SMECs diagnosed at The University of Virginia and compare them with LS-associated and Lynch-like endometrial cancers...
August 10, 2016: International Journal of Gynecological Pathology
https://www.readbyqxmd.com/read/27438990/mlh1-deficient-colorectal-carcinoma-with-wild-type-braf-and-mlh1-promoter-hypermethylation-harbor-kras-mutations-and-arise-from-conventional-adenomas
#14
Lama Farchoukh, Shih-Fan Kuan, Beth Dudley, Randall Brand, Marina Nikiforova, Reetesh K Pai
Between 10% and 15% of colorectal carcinomas demonstrate sporadic DNA mismatch-repair protein deficiency as a result of MLH1 promoter methylation and are thought to arise from sessile serrated adenomas, termed the serrated neoplasia pathway. Although the presence of the BRAF V600E mutation is indicative of a sporadic cancer, up to 30% to 50% of colorectal carcinomas with MLH1 promoter hypermethylation will lack a BRAF mutation. We report the clinicopathologic and molecular features of MLH1-deficient colorectal carcinoma with wild-type BRAF and MLH1 promoter hypermethylation (referred to as MLH1-hypermethylated BRAF wild-type colorectal carcinoma, n=36) in comparison with MLH1-deficient BRAF-mutated colorectal carcinoma (n=113) and Lynch syndrome-associated colorectal carcinoma (n=36)...
October 2016: American Journal of Surgical Pathology
https://www.readbyqxmd.com/read/27422471/primary-colon-adenosquamous-carcinoma-in-a-patient-with-lynch-syndrome-a-new-histologic-subtype-associated-with-microsatellite-instability
#15
Virginia E Duncan, Shuko Harada, Todd M Stevens
We report a case of a 53-year-old woman who presented with rectal bleeding and a 9.5 cm hemicircumferential ascending colon mass. Histology revealed adenosquamous carcinoma (ASC), a rare subtype comprised of malignant squamous and glandular elements. Immunohistochemistry revealed loss of MLH1/PMS2 expression and retained MSH2/MSH6 expression in squamous and glandular components, indicative of microsatellite instability (MSI). MSI is caused by loss-of-function defects in DNA mismatch repair genes, leading to increased susceptibility to a variety of neoplasms; the role of MSI in colorectal ASC is unknown...
October 2016: International Journal of Surgical Pathology
https://www.readbyqxmd.com/read/27404452/characterisation-of-pd-l1-positive-subsets-of-microsatellite-unstable-colorectal-cancers
#16
Jung Ho Kim, Hye Eun Park, Nam-Yun Cho, Hye Seung Lee, Gyeong Hoon Kang
BACKGROUND: The aim of this study was to reveal the clinicopathological and molecular characteristics of microsatellite instability-high (MSI-H) colorectal cancers (CRCs) showing programmed death ligand-1 (PD-L1) positivity, which are good candidates for anti-PD-1/PD-L1 immunotherapy. METHODS: The PD-L1 expression status of 208 MSI-H CRCs was retrospectively analysed using immunohistochemistry. PD-L1 positivity in tumour cells (PD-L1+(T)) and PD-L1 positivity in immune cells (PD-L1+(I)) were separately evaluated...
August 9, 2016: British Journal of Cancer
https://www.readbyqxmd.com/read/27377375/cd80-down-regulation-is-associated-to-aberrant-dna-methylation-in-non-inflammatory-colon-carcinogenesis
#17
Marco Scarpa, Melania Scarpa, Ignazio Castagliuolo, Francesca Erroi, Silvia Basato, Paola Brun, Imerio Angriman, Carlo Castoro
BACKGROUND: The lack of positive costimulatory molecules represents one of the mechanisms by which tumor cells evade immune surveillance. Promoter hypermethylation plays a major role in cancer development through transcriptional silencing of critical genes. The aim of this study was to examine the expression of the costimulatory molecule CD80 in relationship with genomic methylation in non-inflammatory colon carcinogenesis. METHODS: Colonic mucosal samples were collected from healthy subjects (n = 30) and from dysplastic adenoma (n = 14), and colon adenocarcinoma (n = 10)...
2016: BMC Cancer
https://www.readbyqxmd.com/read/27302833/frequent-pik3ca-mutations-in-colorectal-and-endometrial-tumors-with-2-or-more-somatic-mutations-in-mismatch-repair-genes
#18
Stacey A Cohen, Emily H Turner, Mallory B Beightol, Angela Jacobson, Ted A Gooley, Stephen J Salipante, Sigurdis Haraldsdottir, Christina Smith, Sheena Scroggins, Jonathan F Tait, William M Grady, Edward H Lin, David E Cohn, Paul J Goodfellow, Mark W Arnold, Albert de la Chapelle, Rachel Pearlman, Heather Hampel, Colin C Pritchard
BACKGROUND & AIMS: Some colorectal and endometrial tumors with microsatellite instability not attributable to MLH1 hypermethylation or germline mutations contain 2 or more somatic mutations in genes encoding mismatch repair (MMR) proteins. We sought to define the molecular phenotype of this newly recognized tumor subtype. METHODS: From 2 prospective studies of the efficacy of screening for Lynch syndrome, we identified patients with colorectal and endometrial tumors who had 2 or more somatic (but not germline) mutations in genes encoding MMR proteins (double somatic)...
September 2016: Gastroenterology
https://www.readbyqxmd.com/read/27300758/whole-gene-capture-analysis-of-15-crc-susceptibility-genes-in-suspected-lynch-syndrome-patients
#19
Anne M L Jansen, Marije A Geilenkirchen, Tom van Wezel, Shantie C Jagmohan-Changur, Dina Ruano, Heleen M van der Klift, Brendy E W M van den Akker, Jeroen F J Laros, Michiel van Galen, Anja Wagner, Tom G W Letteboer, Encarna B Gómez-García, Carli M J Tops, Hans F Vasen, Peter Devilee, Frederik J Hes, Hans Morreau, Juul T Wijnen
BACKGROUND AND AIMS: Lynch Syndrome (LS) is caused by pathogenic germline variants in one of the mismatch repair (MMR) genes. However, up to 60% of MMR-deficient colorectal cancer cases are categorized as suspected Lynch Syndrome (sLS) because no pathogenic MMR germline variant can be identified, which leads to difficulties in clinical management. We therefore analyzed the genomic regions of 15 CRC susceptibility genes in leukocyte DNA of 34 unrelated sLS patients and 11 patients with MLH1 hypermethylated tumors with a clear family history...
2016: PloS One
https://www.readbyqxmd.com/read/27080585/methylation-analysis-of-dna-repair-genes-in-alzheimer-s-disease
#20
Fabio Coppedè, Pierpaola Tannorella, Andrea Stoccoro, Lucia Chico, Gabriele Siciliano, Ubaldo Bonuccelli, Lucia Migliore
There is substantial evidence of impaired DNA repair activities in Alzheimer's disease (AD) neurons and peripheral tissues, inducing some investigators to speculate that this could partially result from promoter hypermethylation of DNA repair genes, resulting in gene silencing in those tissues. In the present study a screening cohort composed by late-onset AD (LOAD) patients and healthy matched controls was evaluated with a commercially available DNA methylation array for the assessment of the methylation levels of a panel of 22 genes involved in major DNA repair pathways in blood DNA...
April 11, 2016: Mechanisms of Ageing and Development
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