Published online Sep 28, 2019. doi: 10.3748/wjg.v25.i36.5530
Peer-review started: April 30, 2019
First decision: May 30, 2019
Revised: July 16, 2019
Accepted: August 19, 2019
Article in press: Auguet 19, 2019
Published online: September 28, 2019
Processing time: 151 Days and 18.1 Hours
DNA mutational analysis of pancreatic cystic fluid (CF) is a useful adjunct to the evaluation of pancreatic cysts. KRAS/GNAS or RAF/PTPRD/CTNNB1/RNF43 mutations are highly specific to precancerous or advanced neoplasia. Several studies recently demonstrated the ability of next-generation sequencing (NGS) analysis to detect DNA mutations in pancreatic CF, but few studies have yet to perform a systematic comparative analysis between pancreatic CF and neoplastic surgical tissue (NT). The value of CF-NGS analysis indicators for determining surgical resection requires evaluation.
The main subject of this study is to evaluate the diagnostic performance of some specific mutations in CF, and to establish a concordance of detected mutations in CF and NT. The key problem to be solved was to appropriately select patients for preventive pancreatic surgery. It is very important to solve this problem in the future to avoid unnecessary procedures. Future research will be targeted to assess and validate this new technique of non-cancerous cyst prognosis.
The primary objective of this pilot prospective study was to determine the mutational concordance in the molecular biology analysis of paired DNA samples from CF and pancreatic tumor NT. The secondary objective was to analyze specific mutations (KRAS, GNAS, RAF, PTPRD, CTNNB1, RNF43, POLD1, and TP53) to correlate their presence with a final cancer diagnosis. The sensitivity and specificity of the DNA mutational analysis in CF was also evaluated for pancreatic cysts requiring surgery.
Patients requiring surgery for high-risk pancreatic cysts were included in a multicenter prospective pilot study. DNA from CF (collected by Endoscopic Ultrasound-Guided Fine Needle Aspiration Biopsy (EUS-FNA)) and NT (collected by surgery) were analyzed by NGS. The primary objective was to compare the mutation profiles of paired DNA samples. The secondary objective was to correlate the presence of specific mutations (KRAS/GNAS, RAF/PTPRD/CTNNB1/RNF43/POLD1/TP53) with a final cancer diagnosis. Sensitivity and specificity were also evaluated.
Between December 2016 and October 2017, 20 patients were included in this pilot study. Surgery was delayed for three patients. Concordant CF-NT genotypes were found in 15/17 paired DNA, with a higher proportion of mutated alleles in CF than in NT. NGS was possible for all pancreatic CF collected by EUS-FNA. In two cases, the presence of a KRAS/GNAS mutation was discordant between CF and NT. In three patients with NT or pancreatic cysts with high-grade dysplasia, no mutations were found. The sensitivity and specificity of KRAS/GNAS mutations in CF to predict an appropriate indication for surgical resection were 0.78 and 0.62, respectively. The sensitivity and specificity of RAF/PTPRD/CTNNB1/RNF43/POLD1/TP53 mutations in CF were 0.55 and 1.0, respectively.
The main goal of this study was to confirm the concordance between CF and NT mutations. The prognosis of pancreatic cysts can be evaluated by analyzing CF mutations. KRAS, GNAS, RAF, PTPRD, CTNNB1, RNF43, POLD1, and TP53 mutations are good indicators of cyst malignant degeneration risks. This study offers the opportunity to accurately assess pancreatic cyst prognosis using a minimally invasive technique. The new hypothesis assessed in this study is that CF mutations are good indicators of malignant degeneration risks. The new methods proposed in this study involve DNA extraction from a body fluid other than blood. The POLD1 gene might be of interest in the evaluation of the malignant degeneration risks of pancreatic cysts. We confirmed that CF mutations are good indicators of malignant risk. In the future, all patients with pancreatic cysts could benefit from CF analysis collected by EUS-FNA.
All of the collected CF samples were able to be genetically analyzed. The mutations selected for evaluation (KRAS, GNAS, RAF, PTPRD, CTNNB1, RNF43, POLD1, and TP53) were not sufficient and did not provide excellent diagnostic performance. Additional mutations should be identified in the future to improve this diagnostic performance. Future national multicentric research is being implemented, with the collection of all pancreatic cysts of 12 mm-diameter and over. Future research should use the same methodology with comparative CF and NT analyses, but conducted on a larger scale and including the analysis of a higher number of mutations.