Hypermethylation-mediated reduction of WWOX expression in intraductal papillary mucinous neoplasms of the pancreas.
We have previously shown that WW domain-containing oxidoreductase (WWOX) has tumour-suppressing effects and that its expression is frequently reduced in pancreatic carcinoma. In this study, we examined WWOX expression in intraductal papillary mucinous neoplasm of the pancreas (IPMN) to assess the function of WWOX in pancreatic duct tumourigenesis using immunohistochemistry and methylation-specific polymerase chain reaction analysis. Among 41 IPMNs including intraductal papillary mucinous adenomas (IPMAs) and intraductal papillary mucinous carcinomas (IPMCs), loss or reduced WWOX immunoreactivity was detected in 3 (15%) of 20 IPMAs and 17 (81%) of 21 IPMCs. In addition, hypermethylation of the WWOX regulatory site was detected in 1 (33%) of 3 WWOX(-) IPMAs and 9 (53%) of 17 WWOX(-) IPMCs, suggesting that hypermethylation may possibly be important in the suppression of WWOX expression. Reduction of WWOX expression was significantly correlated with a higher Ki-67 labelling index but was not correlated with the ssDNA apoptotic body index. Interestingly, decreased WWOX expression was significantly correlated with loss of SMAD4 expression in these IPMNs. The results indicate that downregulation of WWOX expression by the WWOX regulatory region hypermethylation is critical for transformation of pancreatic duct.
Division of Pathology, Department of Pathology, Kobe University Graduate School of Medicine, Kobe, Japa.
S
S
Nakayama
S
S
Semba
N
N
Maeda
M
M
Matsushita
Y
Y
Kuroda
H
H
Yokozaki
D002288:Adenocarcinoma, Mucinous / Q000235:genetics* / Q000473:pathology; D000368:Aged; D002291:Carcinoma, Papillary / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D019175:DNA Methylation / Q000235:genetics*; D004273:DNA, Neoplasm / Q000235:genetics; D004277:DNA, Single-Stranded / Q000235:genetics; D015536:Down-Regulation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D010088:Oxidoreductases / Q000172:deficiency* / Q000235:genetics*; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000473:pathology; D016133:Polymerase Chain Reaction; D013489:Suppression, Genetic; D025521:Tumor Suppressor Proteins / Q000172:deficiency* / Q000235:genetics*; D000074584:WW Domain-Containing Oxidoreductase
D004273:DNA, Neoplasm; D004277:DNA, Single-Stranded; D025521:Tumor Suppressor Proteins; D010088:Oxidoreductases; D000074584:WW Domain-Containing Oxidoreductase; C486071:WWOX protein, human