Genetic and Epigenetic Markers in Pancreatic Masses
Genetic and Epigenetic Markers in Pancreatic Masses
Background Methylation markers have shown promise in the early diagnosis of pancreatic carcinoma. The aim of this study was to assess the diagnostic utility of hypermethylation status of candidate genes in combination with KRAS mutation detection in the evaluation of pancreatic masses.
Experimental design Sixty-one fine needle aspirates of pancreatic masses (43 pancreatic adenocarcinomas and 18 chronic pancreatitis) were studied. Methylation status of HRH2, EN1, SPARC, CDH13 and APC were analysed using melting curve analysis after DNA bisulfite treatment. KRAS mutations were also analysed.
Results The methylation panel had a sensitivity of 73% (27 of 37, CI 95% 56 to 86%) and a specificity of 100% whenever two or more promoters were found hypermethylated. KRAS mutations showed a sensitivity of 77% (33 of 43, CI 95% 62 to 88%) and a specificity of 100%. Both molecular analyses added useful information to cytology by increasing the number of informative cases. When genetic and epigenetic analyses were combined sensitivity was 84% (36 of 43 CI 95% 69 to 93%) maintaining a 100% specificity.
Conclusions Analysis of hypermethylation status of a panel of genes and KRAS mutation detection offer a similar diagnostic yield in the evaluation of pancreatic masses. The combined molecular analysis increases the number of informative cases without diminishing specificity.
Pancreatic cancer is one of the most aggressive cancers; in Europe the survival at 5 years is less than 5%. Pancreatic mass is a common manifestation of the disease and its accurate evaluation is critical in the management of these patients. Obtaining cellular material by fine-needle aspiration (FNAs), either percutaneously or endoscopically, is the first and often the only sample amenable for pathological examination. Pathological analysis, while sensitive, is hampered by a significant proportion of inconclusive results.
KRAS mutations have been extensively studied as a potential tumour marker for pancreatic cancer. They are detected at high frequency (75–100%), concentrate at codon 12 and are present in pancreatic intraductal neoplasia (PanIN), the earliest neoplastic lesion identified. In previous studies we showed that the KRAS mutations detection in FNA of pancreatic masses enhanced the diagnostic sensitivity of cytological evaluation maintaining a 100% specificity. When analysed in pancreatic juice, duodenal fluid or pancreatic duct brush KRAS mutations offer an improved sensitivity complementing conventional cytology but with diminished specificity.KRAS mutations can be detected in the pancreatic juice of a significant proportion of patients with chronic pancreatitis that will not develop pancreatic carcinomas.
Methylation of the CpG islands in promoters is usually associated with gene silencing. Hypermethylation promoter of many genes is a common and early event in pancreatic tumourigenesis. The diagnostic utility of some methylated markers have been preliminarily evaluated in pancreatic juice with promising results.
The aim of this study was to evaluate the relative contribution of a novel panel of hypermethylated markers to the diagnostic evaluation of FNA of pancreatic masses alone or in combination with KRAS mutations.
Abstract and Introduction
Background Methylation markers have shown promise in the early diagnosis of pancreatic carcinoma. The aim of this study was to assess the diagnostic utility of hypermethylation status of candidate genes in combination with KRAS mutation detection in the evaluation of pancreatic masses.
Experimental design Sixty-one fine needle aspirates of pancreatic masses (43 pancreatic adenocarcinomas and 18 chronic pancreatitis) were studied. Methylation status of HRH2, EN1, SPARC, CDH13 and APC were analysed using melting curve analysis after DNA bisulfite treatment. KRAS mutations were also analysed.
Results The methylation panel had a sensitivity of 73% (27 of 37, CI 95% 56 to 86%) and a specificity of 100% whenever two or more promoters were found hypermethylated. KRAS mutations showed a sensitivity of 77% (33 of 43, CI 95% 62 to 88%) and a specificity of 100%. Both molecular analyses added useful information to cytology by increasing the number of informative cases. When genetic and epigenetic analyses were combined sensitivity was 84% (36 of 43 CI 95% 69 to 93%) maintaining a 100% specificity.
Conclusions Analysis of hypermethylation status of a panel of genes and KRAS mutation detection offer a similar diagnostic yield in the evaluation of pancreatic masses. The combined molecular analysis increases the number of informative cases without diminishing specificity.
Introduction
Pancreatic cancer is one of the most aggressive cancers; in Europe the survival at 5 years is less than 5%. Pancreatic mass is a common manifestation of the disease and its accurate evaluation is critical in the management of these patients. Obtaining cellular material by fine-needle aspiration (FNAs), either percutaneously or endoscopically, is the first and often the only sample amenable for pathological examination. Pathological analysis, while sensitive, is hampered by a significant proportion of inconclusive results.
KRAS mutations have been extensively studied as a potential tumour marker for pancreatic cancer. They are detected at high frequency (75–100%), concentrate at codon 12 and are present in pancreatic intraductal neoplasia (PanIN), the earliest neoplastic lesion identified. In previous studies we showed that the KRAS mutations detection in FNA of pancreatic masses enhanced the diagnostic sensitivity of cytological evaluation maintaining a 100% specificity. When analysed in pancreatic juice, duodenal fluid or pancreatic duct brush KRAS mutations offer an improved sensitivity complementing conventional cytology but with diminished specificity.KRAS mutations can be detected in the pancreatic juice of a significant proportion of patients with chronic pancreatitis that will not develop pancreatic carcinomas.
Methylation of the CpG islands in promoters is usually associated with gene silencing. Hypermethylation promoter of many genes is a common and early event in pancreatic tumourigenesis. The diagnostic utility of some methylated markers have been preliminarily evaluated in pancreatic juice with promising results.
The aim of this study was to evaluate the relative contribution of a novel panel of hypermethylated markers to the diagnostic evaluation of FNA of pancreatic masses alone or in combination with KRAS mutations.