scholarly journals Inactivation of DNA Mismatch Repair by Variants of Uncertain Significance in the PMS2 Gene

2013 ◽  
Vol 34 (11) ◽  
pp. 1477-1480 ◽  
Author(s):  
Mark Drost ◽  
Hester Koppejan ◽  
Niels de Wind
Keyword(s):  
Mismatch Repair ◽  
Dna Mismatch Repair ◽  
Variants Of Uncertain Significance ◽  
Dna Mismatch ◽  
Uncertain Significance ◽  
Pms2 Gene

Prevalence and molecular characteristics of DNA mismatch repair deficient endometrial cancer in a Japanese hospital-based population

2020 ◽  
Vol 51 (1) ◽  
pp. 60-69 ◽  
Author(s):  
Azusa Yamamoto ◽  
Tatsuro Yamaguchi ◽  
Okihide Suzuki ◽  
Tetsuya Ito ◽  
Noriyasu Chika ◽  
...  
Keyword(s):  
Endometrial Cancer ◽  
Lynch Syndrome ◽  
Mismatch Repair ◽  
Dna Mismatch Repair ◽  
Molecular Characteristics ◽  
Variant Of Uncertain Significance ◽  
Dna Mismatch ◽  
Germline Variant ◽  
Uncertain Significance ◽  
Repair Genes

Abstract Background The prevalence and molecular characteristics of defective DNA mismatch repair endometrial cancers in the Japanese population have been underexplored. Data supporting clinical management of patients with Lynch-like syndrome and germline variant of uncertain significance of mismatch repair genes are still lacking. Methods Immunohistochemistry of mismatch repair proteins (MLH1, MSH2, MSH6 and PMS2) was performed on formalin-fixed paraffin-embedded sections prepared from resected primary endometrial cancers in 395 women with a median age of 59 years. Genetic and/or epigenetic alterations of the mismatch repair genes were also investigated. Results Loss of expression of one or more mismatch repair proteins was observed in 68 patients (17.2%). A total of 17 out of 68 patients (25%, 4.3% of all cases) were identified as candidates for genetic testing for Lynch syndrome after excluding 51 patients with MLH1 hypermethylated cancer. Fourteen of these 17 patients subjected to genetic testing were found to have Lynch syndrome (n = 5), germline variant of uncertain significance (n = 2) or Lynch-like syndrome (n = 7). Compared with patients with Lynch syndrome, those with germline variant of uncertain significance and Lynch-like syndrome tended to demonstrate an older age at the time of endometrial cancer diagnosis (P = 0.07), less fulfillment of the revised Bethesda guidelines (P = 0.09) and lower prevalence of Lynch syndrome-associated tumors in their first-degree relatives (P = 0.01). Conclusions This study provides useful information for management in patients with DNA mismatch repair endometrial cancer. Specifically, cancer surveillance as recommended in patients with Lynch syndrome might not be necessary in patients with germline variant of uncertain significance and Lynch-like syndrome and their relatives.

scholarly journals A calibrated cell-based functional assay to aide classification of MLH1 DNA mismatch repair gene variants

2021 ◽  
Author(s):  
Abhijit Rath ◽  
Alexander A Radecki ◽  
Kaussar Rahman ◽  
Rachel B Gilmore ◽  
Jonathan R Hudson ◽  
...  
Keyword(s):  
Mismatch Repair ◽  
Dna Mismatch Repair ◽  
Embryonic Stem ◽  
Mismatch Repair Gene ◽  
Functional Assay ◽  
Repair Gene ◽  
Dna Mismatch ◽  
Uncertain Significance ◽  
Cellular Context ◽  
A Cell

PURPOSE: Functional assays provide important evidence for classifying the disease significance of germline variants in the DNA mismatch repair genes. We sought to develop a cell-based approach for testing the function of variants of uncertain significance (VUS) in the MLH1 gene. METHODS: Using CRISPR gene editing, we knocked-in MLH1 VUS into the endogenous MLH1 loci in human embryonic stem cells. We examined their impact at the RNA and protein level, including their ability to maintain stability of microsatellite sequences and instigate a DNA damage response. We calibrated these assays by testing well-established pathogenic and benign control variants. RESULTS: Five VUS resulted in functionally abnormal protein, 15 VUS resulted in functionally normal protein, and one VUS showed mixed results. Furthermore, we converted the functional outputs into a single odds in favor of pathogenicity score for each VUS. CONCLUSION: Our CRISPR-based functional assay successfully models phenotypes observed in patients in a cellular context. Using this approach, we generated evidence for or against pathogenicity for utilization by variant classification expert panels. Ultimately, this information will assist in proper diagnosis and disease management for suspected Lynch syndrome patients.

Sign in / Sign up

Export Citation Format

Share Document