FNA Smears of Pancreatic Ductal Adenocarcinoma Are Superior to Formalin-Fixed Paraffin-Embedded Tissue as a Source of DNA: Comparison of Targeted KRAS Amplification and Genotyping in Matched Preresection and Postresection Samples

摘要

BACKGROUND: The current study was conducted to compare DNA yield, including normalization to nuclear area, DNA amplification functionality, and detection of KRAS mutations between matched fine-needle aspiration (FNA) specimens and pancreatic resections diagnostic of pancreatic ductal adenocarcinoma. METHODS: A retrospective sample of 30 matched single FNA smears and macrodissected formalin-fixed, paraffin-embedded (FFPE) curls (2 5-mu m curls) were compared by measuring the following: nuclear area (via digital image analysis), DNA yield (via NanoDrop spectrophotometry and Quantus fluorometry), and polymerase chain reaction threshold cycles for KRAS amplifications. Variants in KRAS codons 12/13 and 61 were detected by fluorescent melt curve analyses, followed by Sanger DNA sequencing. RESULTS: Despite a similar nuclear area, FNA smears yielded greater DNA per nuclear area via 2 DNA quantification methods. KRAS codon 12 mutations were detected in 23 of 30 FNA specimens (77%) compared with 17 of 30 matched FFPE specimens (57%), for a concordance rate of 74%. No KRAS codon 13 or 61 mutations were detected. CONCLUSIONS: FNA specimens are a more optimal source of DNA, and represent an important resource in the preresection and postresection molecular analysis of pancreatic ductal adenocarcinoma. (c) 2017 American Cancer Society.