scholarly journals Possible Phenotypic Consequences of Structural Differences in Idic(15) in a Small Cohort of Patients

2019 ◽  
Vol 20 (19) ◽  
pp. 4935
Author(s):  
Márta Czakó ◽  
Ágnes Till ◽  
András Szabó ◽  
Réka Ripszám ◽  
Béla Melegh ◽  
...  
Keyword(s):  
Copy Number ◽  
Clinical Symptoms ◽  
Copy Number Gain ◽  
Genomic Region ◽  
Comparative Genomic ◽  
Chromosome 15 ◽  
Factors Influencing ◽  
15Q Duplication ◽  
Segmental Aneuploidy ◽  
Structural Differences

Among human supernumerary marker chromosomes, the occurrence of isodicentric form of 15 origin is relatively well known due to its high frequency, both in terms of gene content and associated clinical symptoms. The associated epilepsy and autism are typically more severe than in cases with interstitial 15q duplication, despite copy number gain of approximately the same genomic region. Other mechanisms besides segmental aneuploidy and epigenetic changes may also cause this difference. Among the factors influencing the expression of members of the GABAA gene cluster, the imprinting effect and copy number differences has been debated. Limited numbers of studies investigate factors influencing the interaction of GABAA cluster homologues. Five isodicentric (15) patients are reported with heterogeneous symptoms, and structural differences of their isodicentric chromosomes based on array comparative genomic hybridization results. Relations between the structure and the heterogeneous clinical picture are discussed, raising the possibility that the structure of the isodicentric (15), which has an asymmetric breakpoint and consequently a lower copy number segment, would be the basis of the imbalance of the GABAA homologues. Studies of trans interaction and regulation of GABAA cluster homologues are needed to resolve this issue, considering copy number differences within the isodicentric chromosome 15.

scholarly journals Genomic amplification of chromosome 20q13.33 is the early biomarker for the development of sporadic colorectal carcinoma

2020 ◽  
Vol 13 (S10) ◽  
Author(s):  
Vo-Minh-Hoang Bui ◽  
Clément Mettling ◽  
Jonathan Jou ◽  
H. Sunny Sun
Keyword(s):  
Colorectal Carcinoma ◽  
Microsatellite Instability ◽  
Copy Number ◽  
Chromosomal Abnormalities ◽  
Quantitative Polymerase Chain Reaction ◽  
Copy Number Gain ◽  
Comparative Genomic ◽  
Colon Polyps ◽  
Genomic Amplification ◽  
The Third

Abstract Background Colorectal carcinoma (CRC) is the third most common cancer in the world and also the third leading cause of cancer-related mortality in Taiwan. CRC tumorigenesis is a multistep process, starting from mutations causing loss of function of tumor suppressor genes, canonically demonstrated in adenomatous polyposis coli pathogenesis. Although many genes or chromosomal alterations have been shown to be involved in this process, there are still unrecognized molecular events within CRC tumorigenesis. Elucidating these mechanisms may help improve the management and treatment. Methods In this study, we aimed to identify copy number alteration of the smallest chromosomal regions that is significantly associated with sporadic CRC tumorigenesis using high-resolution array-based Comparative Genomic Hybridization (aCGH) and quantitative Polymerase chain reaction (qPCR). In addition, microsatellite instability assay and sequencing-based mutation assay were performed to illustrate the initiation event of CRC tumorigenesis. Results A total of 571 CRC patients were recruited and 377 paired CRC tissues from sporadic CRC cases were used to define the smallest regions with chromosome copy number changes. In addition, 198 colorectal polyps from 160 patients were also used to study the role of 20q13.33 gain in CRC tumorigenesis. We found that gain in 20q13.33 is the main chromosomal abnormalities in this patient population and counts 50.9 and 62.8% in CRC and colon polyps, respectively. Furthermore, APC and KRAS gene mutations were profiled simultaneously and co-analyzed with microsatellite instability and 20q13.33 gain in CRC patients. Our study showed that the frequency of 20q13.33 copy number gain was highest among all reported CRC mutations. Conclusion As APC or KRAS mutations are currently identified as the most important targets for CRC therapy, this study proposes that 20q13.33 copy number gain and the associated chromosomal genes function as promising biomarkers for both early stage detection and targeted therapy of sporadic CRCs in the future.

scholarly journals Improved Statistical Analysis for Array CGH-Based DNA Copy Number Aberrations

2011 ◽  
Vol 10 ◽  
pp. CIN.S8019
Author(s):  
Hongmei Jiang ◽  
Zhong-Zheng Zhu ◽  
Yue Yu ◽  
Simon Lin ◽  
Lifang Hou
Keyword(s):  
Copy Number ◽  
Cancer Metastasis ◽  
Copy Number Gain ◽  
Statistical Hypothesis ◽  
Comparative Genomic ◽  
Statistical Hypothesis Testing ◽  
Dna Copy Number ◽  
Copy Number Aberrations ◽  
Number Pattern ◽  
Dna Copy Number Aberrations

Array-based comparative genomic hybridization (aCGH) allows measuring DNA copy number at the whole genome scale. In cancer studies, one may be interested in identifying DNA copy number aberrations (CNAs) associated with certain clinicopathological characteristics such as cancer metastasis. We proposed to define test regions based on copy number pattern profiles across multiple samples, using either smoothed log2-ratio or discrete data of copy number gain/loss calls. Association test performed on the refined test regions instead of the probes has improved power due to reduced number of tests. We also compared three types of measurement of copy number levels, normalized log2-ratio, smoothed log2-ratio, and copy number gain or loss calls in statistical hypothesis testing. The relative strengths and weaknesses of the proposed method were demonstrated using both simulation studies and real data analysis of a liver cancer study.

scholarly journals Combination of Genome-Wide Polymorphisms and Copy Number Variations of Pharmacogenes in Koreans

2021 ◽  
Vol 11 (1) ◽  
pp. 33
Author(s):  
Nayoung Han ◽  
Jung Mi Oh ◽  
In-Wha Kim
Keyword(s):  
Copy Number ◽  
Genome Wide Association Study ◽  
Copy Number Gain ◽  
Copy Number Variations ◽  
Gene Gain ◽  
Single Nucleotide Variants ◽  
Single Nucleotide ◽  
Haplotype Blocks ◽  
Genome Wide ◽  
Control And Prevention

For predicting phenotypes and executing precision medicine, combination analysis of single nucleotide variants (SNVs) genotyping with copy number variations (CNVs) is required. The aim of this study was to discover SNVs or common copy CNVs and examine the combined frequencies of SNVs and CNVs in pharmacogenes using the Korean genome and epidemiology study (KoGES), a consortium project. The genotypes (N = 72,299) and CNV data (N = 1000) were provided by the Korean National Institute of Health, Korea Centers for Disease Control and Prevention. The allele frequencies of SNVs, CNVs, and combined SNVs with CNVs were calculated and haplotype analysis was performed. CYP2D6 rs1065852 (c.100C>T, p.P34S) was the most common variant allele (48.23%). A total of 8454 haplotype blocks in 18 pharmacogenes were estimated. DMD ranked the highest in frequency for gene gain (64.52%), while TPMT ranked the highest in frequency for gene loss (51.80%). Copy number gain of CYP4F2 was observed in 22 subjects; 13 of those subjects were carriers with CYP4F2*3 gain. In the case of TPMT, approximately one-half of the participants (N = 308) had loss of the TPMT*1*1 diplotype. The frequencies of SNVs and CNVs in pharmacogenes were determined using the Korean cohort-based genome-wide association study.

scholarly journals Genomic Analysis of Response to Neoadjuvant Chemotherapy in Esophageal Adenocarcinoma

Cancers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 3394
Author(s):  
Fereshteh Izadi ◽  
Benjamin Sharpe ◽  
Stella Breininger ◽  
Maria Secrier ◽  
Jane Gibson ◽  
...  
Keyword(s):  
Neoadjuvant Chemotherapy ◽  
Esophageal Adenocarcinoma ◽  
Copy Number ◽  
Tumor Regression ◽  
Locally Advanced ◽  
Genomic Analysis ◽  
Tumor Regression Grade ◽  
Comparative Genomic ◽  
Mutation Burden ◽  
Response To Neoadjuvant Chemotherapy

Neoadjuvant therapy followed by surgery is the standard of care for locally advanced esophageal adenocarcinoma (EAC). Unfortunately, response to neoadjuvant chemotherapy (NAC) is poor (20–37%), as is the overall survival benefit at five years (9%). The EAC genome is complex and heterogeneous between patients, and it is not yet understood whether specific mutational patterns may result in chemotherapy sensitivity or resistance. To identify associations between genomic events and response to NAC in EAC, a comparative genomic analysis was performed in 65 patients with extensive clinical and pathological annotation using whole-genome sequencing (WGS). We defined response using Mandard Tumor Regression Grade (TRG), with responders classified as TRG1–2 (n = 27) and non-responders classified as TRG4–5 (n =38). We report a higher non-synonymous mutation burden in responders (median 2.08/Mb vs. 1.70/Mb, p = 0.036) and elevated copy number variation in non-responders (282 vs. 136/patient, p < 0.001). We identified copy number variants unique to each group in our cohort, with cell cycle (CDKN2A, CCND1), c-Myc (MYC), RTK/PIK3 (KRAS, EGFR) and gastrointestinal differentiation (GATA6) pathway genes being specifically altered in non-responders. Of note, NAV3 mutations were exclusively present in the non-responder group with a frequency of 22%. Thus, lower mutation burden, higher chromosomal instability and specific copy number alterations are associated with resistance to NAC.

scholarly journals Recurring DNA copy number gain at chromosome 9p13 plays a role in the activation of multiple candidate oncogenes in progressing oral premalignant lesions

2014 ◽  
Vol 3 (5) ◽  
pp. 1170-1184 ◽  
Author(s):  
Rebecca Towle ◽  
Ivy F. L. Tsui ◽  
Yuqi Zhu ◽  
Sara MacLellan ◽  
Catherine F. Poh ◽  
...  
Keyword(s):  
Copy Number ◽  
Copy Number Gain ◽  
Premalignant Lesions ◽  
Dna Copy Number
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