Graced by beautiful spring weather in Washington, D.C., the AACR Annual Meeting 2017 brought together scientists from around the globe to share insights into the latest and most exciting cancer research. At the QIAGEN booth, our colleagues shared the latest in QIAGEN innovations, including the revolutionary QIAscout single-cell isolation system, and spoke to customers about NGS, liquid biopsy, bioinformatics solutions and more. They also presented, for the first time, the application note, “QIAscout CTC single cell isolation after AdnaTest CancerSelect pre-enrichment,” which demonstrated a new method for high-quality single cell transcriptomics. Download your copy here!
The Spotlight Presentation on 4/4 featured guest speaker Monika Mehta, Ph.D, a Research Scientist from the Frederick National Laboratory for Cancer Research (FNLCR), and QIAGEN’s own Strategic Marketing Manager Brian Dugan, M.S., MBA. More than 50 people attended to hear Dr. Mehta share her experiences with microRNA sequencing. In her role performing sequencing for the Center for Cancer Research, Dr. Mehta emphasized, data quality is paramount. While she and her team were happy with the kits they were already using for miRNA library construction, she noted that two aspects were limiting; the high sample input requirement of these kits, which could be up to 1 microgram, and the high RNA quality requirement of greater than a RIN value of 7.
To see if they could overcome these issues, her team performed a comparison between the kits they currently used for miRNA library construction and the pre-release and released versions of the QIAseq miRNA Library Kit. Using 4 normal and tumor samples of cellular miRNA, they found that QIAseq yielded increases in the number of miRNA mapped reads for all preps, and increases in the number of novel miRNAs. She also noted that RIN value didn’t appear to affect the results, stating it’s “not a good indicator of quality for miRNA.” Her team also used the QIAseq miRNA Library Kit with exosome-derived miRNA, successfully preparing libraries and sequencing. She pointed out, “These are samples we couldn’t have prepared using any other kit available to us right now.”
Her research was followed by Brian’s in-depth discussion of the QIAseq miRNA Library Kit, including the principle underlying the Unique Molecular Indices, molecular tags that enable quantification of mature miRNAs, and the unique chemistry that the kit uses to drive the reaction toward the miRNA size. He also noted that “The sample is important because it determines the amount of mapped reads you find,” pointing out that mapping rates with the QIAseq kit tend to be 50-60% with cell lines, >75% from tissues, and 15–30% from serum/plasma. Another important note from his portion of the presentation focused around blocking hY4 Y RNA, a major contaminating RNA species in serum/plasma samples that accounts for a large quantity of the off-target reads found in this sample type. He showed data demonstrating that using no hY4 Y RNA blocker takes the percentage of “other RNA reads” collected from 2.5% up to a whopping 40%, and drops miRNA mapped reads from about 40% to about 25%, emphasizing the importance of blocking these contaminating RNA if your primary interest is miRNA sequencing.
QIAGEN’s poster presentations covered a range of topics including circulating tumor DNA, RNA profiles of circulating tumor cells (CTCs) and extracellular vesicles (EVs), and RNA fusion detection in thyroid nodules. I listened to Corinna Keup, M.Sc. of the Department of Gynecology and Obstetrics, University Hospital of Essen, and Siegfried Hauch, PhD, Director of Liquid Biopsy and Site Management for CTC product development at QIAGEN, discuss the poster “RNA profiles of circulating tumor cells and extracellular vesicles for therapy stratification of metastatic breast cancer patients” with many interested visitors. The research presented demonstrated that even though CTCs and EVs are both types of liquid biopsy, they provide very different information. Dr. Hauch explained, “EVs give us an idea about the tissue; they are released from the tissue. But the CTCs cannot represent the tissue – they need to transform to escape the tissue.” Indeed, their data from metastatic breast cancer samples showed markedly distinct gene expression profiles; only a few of the overexpression signals overlapped between CTCs and EVs. HER2 or HER3 related to therapy non-responders, but intriguingly, whereas mTOR in CTCs correlated to therapy responders, mTOR in EVs correlated to non-responders instead. The results highlight not only the utility of RNA profiling in liquid biopsy, but also the importance of recognizing the distinction between liquid biopsy sample types when analyzing these results.
It was exciting to see the advances being made in cancer research, and the promise of more success yet to come. Thank you to all the scientists and industry colleagues who came out to present at the AACR Annual Meeting 2017 this year for making the conference such a rich and interesting event! We will all continue watching with interest to see where today’s research will lead.
Want to know more about the technologies presented at AACR? Check out our upcoming webinars! Browse the calendar