Dataset Information

NRAS germline variant G138R and multiple rare somatic mutations on APC in colorectal cancer patients in Taiwan by next generation sequencing.

ABSTRACT: Colorectal cancer (CRC) arises from mutations in a subset of genes. We investigated the germline and somatic mutation spectrum of patients with CRC in Taiwan by using the AmpliSeq Cancer Hotspot Panel V2. Fifty paired freshly frozen stage 0-IV CRC tumors and adjacent normal tissue were collected. Blood DNA from 20 healthy donors were used for comparison of germline mutations. Variants were identified using an ion-torrent personal genomic machine and subsequently confirmed by Sanger sequencing or pyrosequencing. Five nonsynonymous germline variants on 4 cancer susceptible genes, CDH1, APC, MLH1, and NRAS, were observed in 6 patients with CRC (12%). Among them, oncogene NRAS G138R variant was identified as having a predicted damaging effect on protein function, which has never been reported by other laboratories. CDH1 T340A variants were presented in 3 patients. The germline variants in the cancer patients differed completely from those found in asymptomatic controls. Furthermore, a total of 56 COSMIC and 21 novel somatic variants distributed in 20 genes were detected in 44 (88%) of the CRC samples. High inter- and intra-tumor heterogeneity levels were observed. Nine rare variants located in the ?-catenin binding region of the APC gene were discovered, 7 of which could cause amino acid frameshift and might have a pathogenic effect. In conclusion, panel-based mutation detection by using a high-throughput sequencing platform can elucidate race-dependent cancer genomes. This approach facilitates identifying individuals at high risk and aiding the recognition of novel mutations as targets for drug development.

SUBMITTER: Chang PY

PROVIDER: S-EPMC5122332 | biostudies-literature | 2016 Jun

REPOSITORIES: biostudies-literature

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NRAS germline variant G138R and multiple rare somatic mutations on APC in colorectal cancer patients in Taiwan by next generation sequencing.

Chang Pi-Yueh PY Chen Jinn-Shiun JS Chang Nai-Chung NC Chang Shih-Cheng SC Wang Mei-Chia MC Tsai Shu-Hui SH Wen Ying-Hao YH Tsai Wen-Sy WS Chan Err-Cheng EC Lu Jang-Jih JJ

Oncotarget 20160601 25

Colorectal cancer (CRC) arises from mutations in a subset of genes. We investigated the germline and somatic mutation spectrum of patients with CRC in Taiwan by using the AmpliSeq Cancer Hotspot Panel V2. Fifty paired freshly frozen stage 0-IV CRC tumors and adjacent normal tissue were collected. Blood DNA from 20 healthy donors were used for comparison of germline mutations. Variants were identified using an ion-torrent personal genomic machine and subsequently confirmed by Sanger sequencing or ...[more]

PMID: 27121310

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Project description:The development and innovation of next generation sequencing (NGS) and the subsequent analysis tools have gain popularity in scientific researches and clinical diagnostic applications. Hence, a systematic comparison of the sequencing platforms and variant calling pipelines could provide significant guidance to NGS-based scientific and clinical genomics. In this study, we compared the performance, concordance and operating efficiency of 27 combinations of sequencing platforms and variant calling pipelines, testing three variant calling pipelines-Genome Analysis Tool Kit HaplotypeCaller, Strelka2 and Samtools-Varscan2 for nine data sets for the NA12878 genome sequenced by different platforms including BGISEQ500, MGISEQ2000, HiSeq4000, NovaSeq and HiSeq Xten. For the variants calling performance of 12 combinations in WES datasets, all combinations displayed good performance in calling SNPs, with their F-scores entirely higher than 0.96, and their performance in calling INDELs varies from 0.75 to 0.91. And all 15 combinations in WGS datasets also manifested good performance, with F-scores in calling SNPs were entirely higher than 0.975 and their performance in calling INDELs varies from 0.71 to 0.93. All of these combinations manifested high concordance in variant identification, while the divergence of variants identification in WGS datasets were larger than that in WES datasets. We also down-sampled the original WES and WGS datasets at a series of gradient coverage across multiple platforms, then the variants calling period consumed by the three pipelines at each coverage were counted, respectively. For the GIAB datasets on both BGI and Illumina platforms, Strelka2 manifested its ultra-performance in detecting accuracy and processing efficiency compared with other two pipelines on each sequencing platform, which was recommended in the further promotion and application of next generation sequencing technology. The results of our researches will provide useful and comprehensive guidelines for personal or organizational researchers in reliable and consistent variants identification.

Project description:IntroductionMultiple primary melanomas (MPM) occur up to 8% of patients with cutaneous malignant melanoma (CMM). They are often sporadic harbouring several somatic mutations, but also familial cases harbouring a CDKN2A germline mutation have been describe in Caucasian populations. The aim of this study was to investigate the incidence, the distribution patterns and the impact of known and unknown germline and somatic mutations in patients with MPM from Italy.Materials and methodsOne-hundred and two MPM patients were enrolled for germline mutation analysis, and five patients with at least four MPMs were identified for somatic mutation analysis. The demographic, pathologic and clinical features were retrieved from medical records. Molecular analysis for both germline and somatic mutations was performed in genomic DNA from peripheral blood and tissue samples, respectively, through a next generation sequencing approach, using a specific multiple-gene panel constructed by the Italian Melanoma Intergroup for somatic analysis and a commercial cancer hotspot panel for somatic analysis.ResultsCDKN2A mutations were detected in 6/16 (37.5%) and 3/86 (3.5%) MPM cases with and without family history for melanoma, respectively. Furthermore, multiple MC1R and, to a lesser extent, ATM variants have been identified. BAP1 variants were found only in MPM patients from southern Italy. The most frequent somatic variants were the pathogenic BRAFV600E and TP53, followed by KIT, PIK3CA, KDR, and NRAS. Single APC, ERBB4, MET, JAK3 and other variants with unknown function were also detected.ConclusionsCDNK2A mutation is the most relevant susceptibility mutation in Italian patients with MPM, especially those with a family history for CMM. The prevalence of this mutation and other sequence variants identified in this study varies among specific sub-populations. Furthermore, some heterogeneity in driver somatic mutations between sporadic MPMs has been observed, as well as in a number of associated sequence variants the clinical impact of which needs to be further elucidated.

Dataset Information

NRAS germline variant G138R and multiple rare somatic mutations on APC in colorectal cancer patients in Taiwan by next generation sequencing.

Publications

NRAS germline variant G138R and multiple rare somatic mutations on APC in colorectal cancer patients in Taiwan by next generation sequencing.

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