Project description:We performed a massively parallel screen in human HAP1 cells to identify loss-of-function missense variants in the key DNA mismatch repair factor MSH2. Resulting variant loss-of-function (LOF) scores are strongly concordant with previous functional evidence and available variant classification.
Project description:Heredity is a major cause of ovarian cancer. Lynch syndrome is associated with 10-12% risk of ovarian cancer, diagnosis at young age and a predilection for endometrioid and clear cell tumors. Global gene expression profiling applied to 25 Lynch syndrome-associated and 42 sporadic ovarian cancers revealed 335 differentially expressed genes and involvement of the mTOR and the MAPK/ERK pathways. The clear cell tumors had distinct expression profiles with upregulation of HER2 and apoptosis signaling pathways. The distinct expression profiles provide clues relevant for hereditary tumorigenesis and may be relevant for therapeutic strategies and refined diagnostics in ovarian cancer linked to Lynch syndrome. Ovarian cancers linked to Lynch syndrome (n=25) were compared to a matched series of sporadic ovarian cancers (n=42), selected from a population-based consecutive series in which hereditary was excluded based on family history, normal MMR protein staining and lack of mutations in BRCA1 and BRCA2.
Project description:Background: Mismatch repair (MMR)-deficiency increases the risk of colorectal tumorigenesis. To determine whether the tumors develop on a normal or disturbed epigenetic background and how radiation affects this, we determined genome-wide histone H3 methylation profiles in macroscopic normal intestinal tissue of young radiated and untreated MMR-deficient VCMsh2LoxP/LoxP (Msh2−/−) mice months before tumor onset. Results: Histone H3 methylation increases in Msh2−/− compared to control Msh2+/+ mice. Activating H3K4me3 and H3K36me3 histone marks frequently accumulate at genes that are H3K27me3 or H3K4me3 modified in Msh2+/+ mice, respectively. The genes recruiting H3K36me3 enrich in gene sets associated with DNA repair, RNA processing, and ribosome biogenesis that become transcriptionally upregulated in the developing tumors. A similar epigenetic effect is present in Msh2+/+ mice 4 weeks after a single-radiation hit, whereas radiation of Msh2−/− mice left their histone methylation profiles almost unchanged. Conclusions: MMR deficiency results in genome-wide changes in histone H3 methylation profiles preceding tumor development. Similar changes constitute a persistent epigenetic signature of radiation-induced DNA damage.
Project description:In patients diagnosed as endometrial cancer by thorough pathologic examinations, Lynch syndromes are screened by (1)immunohistochemical staining (for MLH1, MSH2, MSH6 and PMS2), (2) tests of microsatellite instability and (3) clinical criteria (Amsterdam I or II criteria and Bethesda criteria). For patients with any suspicious discoveries of Lynch syndromes from aforementioned screening methods, a molecular diagnosis with next-generation sequencing for mismatch repair genes (MLH1, MSH2, MSH6, PMS2, and EPCAM) is given to confirm Lynch syndromes. For patients of Lynch syndromes and endometrial cancer, relatives of blood lineage are tested by Sanger method or qPCR to find out carriers of mutation genes of Lynch syndromes.
Project description:Expression profiling of FACS purified Lin-cKit+ cells from compound URE-/+::Msh2-/- mice with AML and control animals Analysis of gene expression in Lin-cKit+ cells from three URE-/+::Msh2-/- mice and four wild type controls
Project description:Genomic DNA from 189 wild type Col x CLC, 191 msh2 Col x CLC or 187 msh2 Col x Ler F2 individuals was extracted using CTAB and used to generate sequencing libraries as described (Serra et al 2018 PNAS). Sequencing data was analysed to identify crossovers as previously reported, using the TIGER pipeline (Rowan et al., 2015 G3).
Project description:Lynch syndrome, caused by germline heterozygous mutations of the DNA mismatch repair genes MLH1, MSH2, MSH6 and PMS2, or deletions affecting the EPCAM gene upstream of MSH2, is characterized by a predisposition to early-onset colorectal and additional extracolonic cancers. An alternative but rare cause of Lynch syndrome is a constitutional epimutation of MLH1, which is characterized by promoter methylation and transcriptional silencing of a single allele in normal tissues. Worldwide, five families with autosomal dominant transmission of a constitutional MLH1 epimutation linked to an MLH1 haplotype with two single nucleotide variants (c.-27C>A and c.85G>T) have been identified. Array-based genotyping using Affymetrix SNP 6.0 data in four of these families revealed a shared haplotype extending across a ≤2.6 Mb region of chromosome 3p22 encompassing MLH1 and additional flanking genes, indicating common ancestry.
Project description:Lynch syndrome, caused by germline heterozygous mutations of the DNA mismatch repair genes MLH1, MSH2, MSH6 and PMS2, or deletions affecting the EPCAM gene upstream of MSH2, is characterized by a predisposition to early-onset colorectal and additional extracolonic cancers. An alternative but rare cause of Lynch syndrome is a constitutional epimutation of MLH1, which is characterized by promoter methylation and transcriptional silencing of a single allele in normal tissues. Worldwide, five families with autosomal dominant transmission of a constitutional MLH1 epimutation linked to an MLH1 haplotype with two single nucleotide variants (c.-27C>A and c.85G>T) have been identified. Array-based genotyping using Affymetrix SNP 6.0 data in four of these families revealed a shared haplotype extending across a ≤2.6 Mb region of chromosome 3p22 encompassing MLH1 and additional flanking genes, indicating common ancestry. Genomic DNA from 5 carriers of the c.-27C>A and c.85G>T variants was hybridized on Affymetrix SNP6.0 array according to manufacturer's procedures
