Abstract 4933: Sanger sequencing of low amount of genomic DNA and FFPE DNA with PCR primers derived from the Ion AmpliSeq cancer hotspot panel

The introduction of defined Ion AmpliSeq™ panels for detection and characterization of actionable mutations occurring in tumor tissue has the potential to revolutionize translational oncology research. The Ion Ampliseq™ cancer hotspot panel version 2 (CHP v2) by Ion Torrent includes 207 actionable mutation targets present in 50 genes and the more comprehensive Ion Oncomine™ cancer panel (OCP) contains over 2000 mutations. A hallmark of these Ion Torrent Ampliseq cancer panels is the low amount of input DNA needed which is critical when the clinical specimen material is limited such as with fine needle biopsy or FFPE samples. Typically, 10 ng of DNA obtained from these sources is sufficient to produce informative sequencing data. Often, cancer-causing or promoting mutations are detected at relatively low allele frequencies like 10-20% compared to the major normal allele. Many researchers wish to verify these findings of low frequency mutations by an orthologous method such as traditional dye-fluorescent Sanger sequencing on a capillary electrophoresis (CE) instrument such as the Applied Biosystems 3500 genetic analyzer. To that end, we have developed a workflow that enables the amplification and traditional Sanger sequencing of individual Ion AmpliSeq targets directly from the AmpliSeq library starting material. The method requires a retainer of 1 μl (∼ 5%) of the original AmpliSeq preamplification material. A dilution of this aliquot is used as template source for individualized PCR/sequencing reactions. We show that a random selection of 48 targets from the CHPv2 panel could be successfully amplified and Sanger-sequenced from an Ion Torrent Ampliseq library originally prepared from 10 ng of FFPE DNA. Furthermore, we show the successful Sanger-re-sequencing of all individual 24 targets covering the TP53 exons from the same sample processed and pre-amplified with the OncoMine AmpliSeq panel. Taken together, this method will enable researchers to reflex-test potential mutations of interest from very material-limited specimen using Sanger CE sequencing. Citation Format: Edgar H. Schreiber, Adam Broomer, Mark Andersen, Kamini Varma. Sanger sequencing of low amount of genomic DNA and FFPE DNA with PCR primers derived from the Ion AmpliSeq cancer hotspot panel. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4933. doi:10.1158/1538-7445.AM2015-4933