Project description:Background & Aims: In gastrointestinal stromal tumors (GIST) KIT exon 11 deletions are associated with poor prognosis. The aim of this study was to determine the gene expression profile of GIST carrying KIT exon 11 deletions and to identify genes associated with poor prognosis. Methods: Expression profiling was performed on 9 tumors with KIT exon 11 deletions and 7 without KIT exon 11 mutations using oligonucleotide microarrays. In addition, gene expression profiles for 35 GISTs were analysed by meta-analysis. Differentially expressed genes were identified and confirmed by qPCR. Expression of CD133 (prominin-1) protein (AC133) was also examined by tissue microarray (TMA) analysis of 204 GISTs from a population-based study in Western Sweden. Survival analysis was performed using Cox regression model. Results: Gene expression profiling, meta-analysis and qPCR demonstrated up-regulation of the stem cell marker CD133 in GIST carrying KIT exon 11 deletions. Immunohistochemical analysis on TMA confirmed CD133 expression in 28% of all tumors. CD133 positivity was frequent in gastric GIST (48%) versus small intestinal GIST (4%). CD133 positivity was also frequent in GIST with KIT exon 11 mutations (41%) compared to tumors with mutations in KIT exon 9, PDGFRA, or wild-type tumors (0-17%). There was no significant correlation between CD133 staining and NIH risk score. Survival analysis demonstrated significant correlation between presence of CD133 and shorter overall survival. Conclusions: The stem cell marker CD133 is expressed in a subset of predominantly gastric GIST with KIT exon 11 mutations and associated with poor prognosis.
Project description:Background & Aims: In gastrointestinal stromal tumors (GIST) KIT exon 11 deletions are associated with poor prognosis. The aim of this study was to determine the gene expression profile of GIST carrying KIT exon 11 deletions and to identify genes associated with poor prognosis. Methods: Expression profiling was performed on 9 tumors with KIT exon 11 deletions and 7 without KIT exon 11 mutations using oligonucleotide microarrays. In addition, gene expression profiles for 35 GISTs were analysed by meta-analysis. Differentially expressed genes were identified and confirmed by qPCR. Expression of CD133 (prominin-1) protein (AC133) was also examined by tissue microarray (TMA) analysis of 204 GISTs from a population-based study in Western Sweden. Survival analysis was performed using Cox regression model. Results: Gene expression profiling, meta-analysis and qPCR demonstrated up-regulation of the stem cell marker CD133 in GIST carrying KIT exon 11 deletions. Immunohistochemical analysis on TMA confirmed CD133 expression in 28% of all tumors. CD133 positivity was frequent in gastric GIST (48%) versus small intestinal GIST (4%). CD133 positivity was also frequent in GIST with KIT exon 11 mutations (41%) compared to tumors with mutations in KIT exon 9, PDGFRA, or wild-type tumors (0-17%). There was no significant correlation between CD133 staining and NIH risk score. Survival analysis demonstrated significant correlation between presence of CD133 and shorter overall survival. Conclusions: The stem cell marker CD133 is expressed in a subset of predominantly gastric GIST with KIT exon 11 mutations and associated with poor prognosis. Tumors with and without KIT exon 11 deletion were compared using a common reference design.
Project description:Imatinib is the current standard treatment for advanced GIST. Previous studies have shown that GIST genotype was associated with treatment outcomes with exon 11 having superior outcome compared with exon 9 or WT.10, 11 In patients with exon 9 kit mutation, the response rate was higher at when imatinib was given at 800mg daily compared with the standard dose of 400mg daily. Although the data linking tyrosine kinase mutation status and imatinib response in metastatic GISTs is intriguing, more information is needed before mutation testing is adopted as part of the routine analysis of high-risk or overtly malignant KIT-expressing GISTs.25 Despite the fact that exon 9 mutations are associated with a lower response rate, overall survival does not appear to be better with high-dose therapy. The investigators propose to conduct a retrospective analysis of mutational analysis on patients with GIST and determine the relationship between patient response and imatinib dose.
Project description:Previous studies of congenic lines of C57BL/6J-DBA/2J mice compared to C57BL/6 mice revealed a 0.23 QTL for sensitivity to methamphetamine on chromosome 11, which contains two protein coding genes, Rufy1 and Hnrnph1. Subsequent transcription activator-like effector nucleases (TALENs)-mediated introduction of frameshift deletions in the first coding exon of one copy of Hnrnph1 of C57BL/6J mice, revealed comparable association to phenotype. Analysis of the transcriptome and splicesome between these Hnrnph1 heterozygous knockouts and C57BL/6J mice revealed genome-wide differentially expression and exon usage of more than 1000 genes in either.
Project description:We report on the analyses of four unrelated patients with de novo, overlapping, hemizygous deletions of the long arm of chromosome 10. These include two small terminal deletions (10q26.2 to 10qter), a larger terminal deletion (10q26.12 to 10qter), and an interstitial deletion (10q25.3q26.13). Single nucleotide polymorphism (SNP) studies (Illumina 550 K) established that these deletions resulted in the hemizygous loss of approximately 6.1, approximately 6.1, approximately 12.5, and approximately 7.0 Mb respectively. Additionally, these data establish that Patients 1, 2, and 3 share common, distal, hemizygous deleted regions of 6.09 Mb containing 37 RefSeq genes. Patients 3 and 4 share a 2.52 Mb deleted region corresponding to the proximal deleted region of Patient 3 and the distal deleted region of Patient 4. This common, hemizygous region contains 20 RefSeq genes including two H6 family homeobox genes (HMX2 and HMX3). Based on previous reports that Hmx2/Hmx3 knockout mice have vestibular anomalies, we propose that hemizygous deletions of HMX2 and HMX3 are responsible for the inner ear malformations observed from CT images, vestibular dysfunction, and congenital sensorineural hearing loss found in Patients 3 and 4. Four cases were identified as having hemizygous 10q deletions through g-banding. These were analyzed with SNP microarrays as well as parents (controls) for cases 1 and 4.
Project description:We report on the analyses of four unrelated patients with de novo, overlapping, hemizygous deletions of the long arm of chromosome 10. These include two small terminal deletions (10q26.2 to 10qter), a larger terminal deletion (10q26.12 to 10qter), and an interstitial deletion (10q25.3q26.13). Single nucleotide polymorphism (SNP) studies (Illumina 550 K) established that these deletions resulted in the hemizygous loss of approximately 6.1, approximately 6.1, approximately 12.5, and approximately 7.0 Mb respectively. Additionally, these data establish that Patients 1, 2, and 3 share common, distal, hemizygous deleted regions of 6.09 Mb containing 37 RefSeq genes. Patients 3 and 4 share a 2.52 Mb deleted region corresponding to the proximal deleted region of Patient 3 and the distal deleted region of Patient 4. This common, hemizygous region contains 20 RefSeq genes including two H6 family homeobox genes (HMX2 and HMX3). Based on previous reports that Hmx2/Hmx3 knockout mice have vestibular anomalies, we propose that hemizygous deletions of HMX2 and HMX3 are responsible for the inner ear malformations observed from CT images, vestibular dysfunction, and congenital sensorineural hearing loss found in Patients 3 and 4.
Project description:Loss of human leukocyte antigen (HLA) expression on tumor cells is frequent in diffuse large B cell lymphoma (DLBCL) arising in immune-privileged sites such as the testis and central nervous system and is associated with small homozygous deletions of HLA-DQ/DR and larger hemizygous deletions of the major histocompatibility complex (MHC) region. To better understand the significance of downregulation of HLA class II expression in relation to the homozygous and hemizygous deletions, we analyzed global gene expression patterns in a series of 26 testicular diffuse large B-cell lymphomas (DLBCL) after characterization of these deletions. Low levels of HLA-DR mRNA in whole testicular DLBCL samples were associated with a strong downregulation of numerous immune-related genes specific for T-cells, macrophages, antigen presentation and processing, lymphocyte activation, chemokines and chemokine receptors and the complement system. Interestingly, hemizygous and homozygous deletions in the MHC region did not have any additional impact on global gene expression. Keywords: Gene expression