Targeted Exome Sequencing Outcome Variations of Colorectal Tumors within and across Two Sequencing PlatformsHassan Ashktorab1*, Hamed Azimi1, Mike Nickerson4*, Sara Bass4, Sudhir Varma3 and Hassan Brim2
- *Corresponding Author:
- Hassan Ashktorab
Howard University College of Medicine
2041 Georgia Avenue, Washington DC
E-mail: [email protected]
Michael L. Nickerson
Center for Cancer Research
National Cancer Institute, Frederick, USA
E-mail: [email protected]
Received date: December 09, 2015; Accepted date: March 09, 2016; Published date: March 14, 2016
Citation: Ashktorab H, Azimi H, Nickerson M, Bass S, Varma S, et al. (2016) Targeted Exome Sequencing Outcome Variations of Colorectal Tumors within and across Two Sequencing Platforms. Next Generat Sequenc & Applic 3:123. doi:10.4172/2469-9853.1000123
Copyright: © 2016 Ashktorab H, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Background and Aim: Next generation sequencing (NGS) has quickly the tool of choice for genome and exome data generation. The multitude of sequencing platforms as well as the variabilities within each platform need to be assessed. In this paper we used two platforms (Ion Torrent and Illumina) to assess single nucleotides variants in colorectal cancer (CRC) specimens.
Methods: CRC specimens (n = 13) collected from 6 CRC (cancer and matched normal) patients were used to establish the mutational profile using Ion Torrent and Illumina sequencing platforms. We analyzed a set of samples from Formalin Fixed Paraffin Embedded and Fresh Frozen (FF) samples on both platforms to assess the effect of sample nature (FFPE vs. FF) on sequencing outcome and to evaluate the similarity/differences of SNVs across the two platforms. In addition, duplicates of fresh frozen samples were sequenced on each platform to assess variability within platform.
Results: The comparison of fresh frozen replicates to each other gave a concordance of 77% (± 15.3%) in Ion Torrent and 70% (± 3.7%) in Illumina. FFPE vs. Fresh Frozen replicates gave a concordance of 40% (± 32%) in Ion Torrent and 49% (± 19%) in Illumina. For the cross platform concordance were FFPE compared to fresh frozen (Average of 75% (± 9.8%) for FFPE samples and 67% (± 32%) for fresh frozen and 70% (± 26.8%) overall average).
Conclusion: Our data show a significant variability within and across platforms. Also the number of detected variants depend on the nature of the specimen; fresh frozen vs. FFPE. Validation of NGS discovered mutations is a must to rule-out false positive mutants. This validation might either be performed through a second NGS platform or through Sanger sequencing.