1. Reliable gene expression measurements from fine needle aspirates of pancreatic tumors: effect of amplicon length and quality assessment.
- Author
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Anderson MA, Brenner DE, Scheiman JM, Simeone DM, Singh N, Sikora MJ, Zhao L, Mertens AN, and Rae JM
- Subjects
- Animals, Base Sequence, Biopsy, Needle, DNA Primers, Glyceraldehyde-3-Phosphate Dehydrogenases genetics, Humans, Mice, Mice, Inbred BALB C, Mice, Nude, Pancreatic Neoplasms enzymology, Pancreatic Neoplasms pathology, Reproducibility of Results, Reverse Transcriptase Polymerase Chain Reaction, Gene Expression, Pancreatic Neoplasms genetics
- Abstract
Background and Aims: Biomarker use for pancreatic cancer diagnosis has been impaired by a lack of samples suitable for reliable quantitative RT-PCR (qRT-PCR). Fine needle aspirates (FNAs) from pancreatic masses were studied to define potential causes of RNA degradation and develop methods for accurately measuring gene expression., Methods: Samples from 32 patients were studied. RNA degradation was assessed by using a multiplex PCR assay for varying lengths of glyceraldehyde-3-phosphate dehydrogenase, and effects on qRT-PCR were determined by using a 150-bp and a 80-bp amplicon for RPS6. Potential causes of and methods to circumvent RNA degradation were studied by using FNAs from a pancreatic cancer xenograft., Results: RNA extracted from pancreatic mass FNAs was extensively degraded. Fragmentation was related to needle bore diameter and could not be overcome by alterations in aspiration technique. Multiplex PCR for glyceraldehyde-3-phosphate dehydrogenase could distinguish samples that were suitable for qRT-PCR. The use of short PCR amplicons (<100 bp) provided reliable gene expression analysis from FNAs. When appropriate samples were used, the assay was highly reproducible for gene copy number with minimal (0.0003 or about 0.7% of total) variance., Conclusions: The degraded properties of endoscopic FNAs markedly affect the accuracy of gene expression measurements. Our novel approach to designate specimens "informative" for qRT-PCR allowed accurate molecular assessment for the diagnosis of pancreatic diseases.
- Published
- 2010
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