TY - JOUR
T1 - KRAS mutation testing on all non-malignant diagnosis of pancreatic endoscopic ultrasound-guided fine-needle aspiration biopsies improves diagnostic accuracy
AU - Trisolini, Elena
AU - Armellini, Elia
AU - Paganotti, Alessia
AU - Veggiani, Claudia
AU - Bozzola, Cristina
AU - Frattini, Milo
AU - Pizio, Corinna
AU - Mancuso, Giuseppe
AU - Andorno, Silvano
AU - Boldorini, Renzo
N1 - Publisher Copyright:
© 2017 Royal College of Pathologists of Australasia
PY - 2017/6
Y1 - 2017/6
N2 - Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is the procedure of choice for the cytologic diagnosis of pancreatic masses. The specificity of EUS-FNA approaches 100%, but the sensitivity is still low, and the high rate of indeterminate (atypical and suspicious) and false-negative results needs improvement. KRAS gene is frequently mutated in pancreatic ductal adenocarcinoma (PDAC) (up to 90%), and mutation analysis of KRAS has been proposed as diagnostic biomarker of PDAC. In most laboratories, KRAS mutation testing is performed by Sanger sequencing or real time-quantitative polymerase chain reaction (RT-qPCR), but these methods may give false-negative results in routine samples, mainly due to low cellularity. In order to increase the sensitivity of EUS-FNA, we propose a sequential approach for detecting KRAS mutations using mutant enriched-PCR (ME-PCR, sensitivity up to 0.1%) in cytologically indeterminate and negative samples tested wild-type by RT-qPCR. EUS-FNA specimens from 107 patients with pancreatic masses (51 males, 56 females, mean age 67 years) were cytologically examined. According to the Papanicolaou Society of Cytopathology guidelines, 50 cases (47%) were classified malignant, 15 (14%) suspicious, 13 (12%) atypical and 10 (9%) negative for malignancy; 18 cases (17%) were non-diagnostic. The overall specificity and sensitivity of cytological examination were 100% and 61%, respectively, when only negative and positive cases were considered; when atypical and suspicious were added to positive cases, the sensitivity increased to 95.1% and the specificity decreased to 85.7%. In all the cases, DNA was extracted from the cell-block and KRAS mutations were investigated by RT-qPCR, followed by ME-PCR in non-amplifiable and negative cases. The overall sensitivity and specificity of KRAS mutation testing alone were 79.3% and 100%; when KRAS mutation testing was performed in indeterminate and negative cytology, the sensitivity increased to 90% with specificity to 100%. Our data indicate that conventional cytology from EUS-FNA samples is highly specific for the diagnosis of pancreatic cancer. Indeterminate and negative cases need to be screened for KRAS mutations; this two-step approach may greatly improve the diagnostic accuracy of this method.
AB - Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is the procedure of choice for the cytologic diagnosis of pancreatic masses. The specificity of EUS-FNA approaches 100%, but the sensitivity is still low, and the high rate of indeterminate (atypical and suspicious) and false-negative results needs improvement. KRAS gene is frequently mutated in pancreatic ductal adenocarcinoma (PDAC) (up to 90%), and mutation analysis of KRAS has been proposed as diagnostic biomarker of PDAC. In most laboratories, KRAS mutation testing is performed by Sanger sequencing or real time-quantitative polymerase chain reaction (RT-qPCR), but these methods may give false-negative results in routine samples, mainly due to low cellularity. In order to increase the sensitivity of EUS-FNA, we propose a sequential approach for detecting KRAS mutations using mutant enriched-PCR (ME-PCR, sensitivity up to 0.1%) in cytologically indeterminate and negative samples tested wild-type by RT-qPCR. EUS-FNA specimens from 107 patients with pancreatic masses (51 males, 56 females, mean age 67 years) were cytologically examined. According to the Papanicolaou Society of Cytopathology guidelines, 50 cases (47%) were classified malignant, 15 (14%) suspicious, 13 (12%) atypical and 10 (9%) negative for malignancy; 18 cases (17%) were non-diagnostic. The overall specificity and sensitivity of cytological examination were 100% and 61%, respectively, when only negative and positive cases were considered; when atypical and suspicious were added to positive cases, the sensitivity increased to 95.1% and the specificity decreased to 85.7%. In all the cases, DNA was extracted from the cell-block and KRAS mutations were investigated by RT-qPCR, followed by ME-PCR in non-amplifiable and negative cases. The overall sensitivity and specificity of KRAS mutation testing alone were 79.3% and 100%; when KRAS mutation testing was performed in indeterminate and negative cytology, the sensitivity increased to 90% with specificity to 100%. Our data indicate that conventional cytology from EUS-FNA samples is highly specific for the diagnosis of pancreatic cancer. Indeterminate and negative cases need to be screened for KRAS mutations; this two-step approach may greatly improve the diagnostic accuracy of this method.
KW - KRAS
KW - Pancreatic ductal adenocarcinoma
KW - cytology
KW - endoscopic ultrasound-guided fine-needle aspiration
KW - mutant enriched-PCR
KW - real time-qPCR
UR - http://www.scopus.com/inward/record.url?scp=85018828075&partnerID=8YFLogxK
U2 - 10.1016/j.pathol.2016.12.348
DO - 10.1016/j.pathol.2016.12.348
M3 - Article
SN - 0031-3025
VL - 49
SP - 379
EP - 386
JO - Pathology
JF - Pathology
IS - 4
ER -