Genetic and epigenetic alterations of familial pancreatic cancers.

Background: Little is known about the genetic and epigenetic changes that contribute to familial pancreatic cancers. The aim of this study was to compare the prevalence of common genetic and epigenetic alterations in sporadic and familial pancreatic ductal adenocarcinomas.

Methods: DNA was isolated from the microdissected cancers of 39 patients with familial and 36 patients with sporadic pancreatic adenocarcinoma.

Synchronous and metachronous extrapancreatic malignant neoplasms in patients with intraductal papillary-mucinous neoplasm of the pancreas.

Background/aims: Patients with intraductal papillary-mucinous neoplasm (IPMN) of the pancreas are likely to have a better prognosis than those with conventional pancreatic ductal adenocarcinoma. Recently there have been some reports on extrapancreatic malignant neoplasms (EPM) occurring in patients with IPMN. The purpose of this study was to discover the characteristic features of IPMN with EPM compared with IPMN without EPM.

Characteristic clinicopathological features of the types of intraductal papillary-mucinous neoplasms of the pancreas.

Objectives: Intraductal papillary-mucinous neoplasm (IPMN) of the pancreas encompasses a spectrum of neoplasms with both morphological and immunohistochemical variations of mucin glycoproteins. Recently, a consensus nomenclature and criteria were histologically defined for classifying these variants of IPMNs into gastric, intestinal, pancreatobiliary, and oncocytic types. The purpose of this study was to determine associations between the histological types and clinicopathological features in patients with IPMN.

Sensitive and quantitative detection of KRAS2 gene mutations in pancreatic duct juice differentiates patients with pancreatic cancer from chronic pancreatitis, potential for early detection.

KRAS2 gene mutations are found in 75-90% of infiltrating pancreatic ductal adenocarcinomas but can also be present with other nonneoplastic pancreatic diseases. We recently developed a novel sensitive assay for point mutation detection, called "LigAmp", which can detect one mutant molecule in the presence of 10,000 wild-type molecules and can quantify mutant DNA over a wide dynamic range. We analyzed KRAS2 mutations in surgically-collected pancreatic duct juice samples from patients with pancreatic adenocarcinoma (n = 27) and chronic pancreatitis(n = 9).

Genome-wide allelotypes of familial pancreatic adenocarcinomas and familial and sporadic intraductal papillary mucinous neoplasms.

Purpose: Most familial cancer susceptibility genes are tumor suppressor genes that are biallelically inactivated in familial neoplasms through somatic deletion of the wild-type allele. Identifying the genomic losses that occur in pancreatic neoplasms, particularly those that occur in familial and precursor neoplasms, may help localize the genes responsible for pancreatic cancer susceptibility.

Experimental Design: Normal and neoplastic tissue DNA was isolated from fresh-frozen surgically resected tissues from 20 patients with primary familial pancreatic adenocarcinoma (defined as having at least one first-degree relative with pancreatic cancer), 31 with sporadic intraductal papillary mucinous neoplasms (IPMN), and 7 with familial IPMNs using laser capture microdissection.

Intraductal papillary-mucinous adenocarcinoma in the remnant pancreas after pancreatoduodenectomy for cancer of Vater's papilla associated with intraductal papillary-mucinous adenoma.

A 72-year-old woman, who had undergone pylorus-preserving pancreatoduodenectomy 3 years before for cancer of Vater's papilla associated with a branch-type intraductal papillary-mucinous adenoma (IPMA), developed dilatation of the main duct and a nodular lesion in the remnant pancreas. Total pancreatectomy was performed, which revealed that the lesion was intraductal papillary-mucinous adenocarcinoma (IPMC) with minimal invasion, suggesting the metachronous multicentric occurrence of this intraductal papillary-mucinous neoplasm (IPMN). Because there were no malignant cells at the pancreaticojejunostomy, and because the histological appearance of the main-duct IPMC was different from that of the IPMA in the primary specimen, the main-duct IPMC was thought to be of different origin from the IPMA.

Detecting low-abundance p16 and p53 mutations in pancreatic juice using a novel assay: heteroduplex analysis of limiting dilution PCRs.

We have developed a simple, robust, highly-sensitive assay for identifying gene mutations in clinical samples. We applied this assay to detect p53 and p16 mutations in pancreatic juice obtained from patients undergoing evaluation and treatment of pancreatic disease. The assay strategy involves PCR amplifying DNA at limiting dilution (LD-PCR) followed by screening PCR products for mutations using temperature gradient capillary electrophoresis (TGCE).

Multifocal neoplastic precursor lesions associated with lobular atrophy of the pancreas in patients having a strong family history of pancreatic cancer.

We screened 116 patients with a strong family history of pancreatic cancer using a combination of endoscopic ultrasound and computed tomography. Ten of these patients underwent surgical resection at our institution, providing an opportunity to define the morphology of pancreatic precursor lesions in patients with a strong family history of pancreatic cancer. Eight of the 10 pancreata were available and these were entirely submitted for histologic examination.

DNA methylation alterations in the pancreatic juice of patients with suspected pancreatic disease.

Molecular markers of pancreatic neoplasia could aid in the evaluation of visible pancreatic lesions and indicate neoplasia invisible to imaging. We evaluated methylation-specific PCR (MSP) assays that detect aberrantly methylated DNA for their use as markers of pancreatic neoplasia. Methylation analysis was done on pancreatic juice collected endoscopically or surgically from 155 individuals with suspected pancreatic disease: 56 patients had pancreatic ductal adenocarcinoma, 17 had intraductal papillary mucinous neoplasms, 26 had symptomatic chronic pancreatitis, 12 controls lacked evidence of pancreatic disease, and 44 were asymptomatic individuals at increased risk of developing familial pancreatic cancer undergoing screening for pancreatic neoplasia.

Pancreaticobiliary cancers with deficient methylenetetrahydrofolate reductase genotypes.

Background & Aims: Methyl group deficiency might promote carcinogenesis by inducing DNA breaks and DNA hypomethylation. We hypothesized that deficient methylenetetrahydrofolate reductase (MTHFR) genotypes could promote pancreatic cancer development.

Methods: First, we performed a case-control study of germline MTHFR polymorphisms (C677T, A1298C) in 303 patients with pancreatic cancer and 305 matched control subjects.

Epigenetic down-regulation of CDKN1C/p57KIP2 in pancreatic ductal neoplasms identified by gene expression profiling.

Purpose: Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is an increasingly identified precursor to infiltrating ductal adenocarcinoma. Although our knowledge of the clinical and pathologic features of IPMNs is increasing, the molecular mechanisms underlying these neoplasms remain poorly understood.

Experimental Designs: To provide further insight into the molecular pathobiology of IPMNs, global expression profiling was done to determine genes that are inactivated/down-regulated in IPMNs using oligonucleotide microarrays (Affymetrix).

Distinct progression pathways involving the dysfunction of DUSP6/MKP-3 in pancreatic intraepithelial neoplasia and intraductal papillary-mucinous neoplasms of the pancreas.

DUSP6/MKP-3 is identified as a candidate tumor suppressor gene for pancreatic cancer. The aim of this study was to elucidate the roles of DUSP6 in the pancreatic carcinogenesis through the pancreatic intraepithelial neoplasia and/or intraductal papillary-mucinous neoplasms, both of which are considered to be precursor lesions of invasive carcinoma of the pancreas, by comparing with involvements of other major tumor suppressive pathways. Expressions of DUSP6, CDKN2A, TP53, and SMAD4 were investigated by immunohistochemistry in a total of 206 lesions of dysplastic ductal precursors and carcinomas retrieved from 52 pancreata with invasive ductal carcinomas and 51 of those with intraductal papillary-mucinous neoplasms.

Chromosome 12, frequently deleted in human pancreatic cancer, may encode a tumor-suppressor gene that suppresses angiogenesis.

Several lines of evidence have suggested that the long arm of chromosome 12 may carry a tumor-suppressor gene(s) that plays a role in pancreatic ductal carcinogenesis. We have previously found a significant association between loss of heterozygosity of the 12q arm and a poor prognosis in pancreatic cancer patients. In this study, we introduced a normal copy of chromosome 12 into some pancreatic ductal carcinoma cells.

Functional analysis of chromosome 18 in pancreatic cancer: strong evidence for new tumour suppressor genes.

Background: In a previous work, we demonstrated that loss of heterozygosity of 18q is a frequent event significantly associated with poor prognosis in pancreatic cancer. We hypothesized that restoration of heterozygosity of chromosome 18 in pancreatic cancer cells would reduce their tumorigenicity. This study was intended to provide functional evidence for the existence of new tumour suppressor gene(s) located on chromosome 18.

The role of chromosome 18 abnormalities in the progression of pancreatic adenocarcinoma.

To date, the events that mediate tumor progression in pancreatic cancer are still poorly understood. Cytogenetic, allelotype, and somatic cell hybrid studies in human pancreatic adenocarcinoma have suggested that chromosome 18 may carry tumor suppressor genes (TSGs), including SMAD4. We previously identified that LOH of 18q at the SMAD4 locus, along with LOHs on 17p and 12q, positively associated with poor prognoses of pancreatic cancer patients.

Restoration of SMAD4 by gene therapy reverses the invasive phenotype in pancreatic adenocarcinoma cells.

SMAD4 is a critical cofactor in signal transduction pathways activated in response to transforming growth factor-beta (TGF-beta)-related ligands, regulating cell growth and differentiation. The roles played by SMAD4 inactivation in tumours highlighted it as a tumour-suppressor gene. However, restoration of the TGF-beta antiproliferative pathway following SMAD4 gene transfer in null-tumour cell lines is controversial.

Gene therapy for pancreatic cancer based on genetic characterization of the disease.

In order to develop an effective therapeutic intervention for patients with pancreatic cancer, we analyzed the association of loss of heterozygosity (LOH) with the clinicopathological features of the disease. Based on these results, we are developing a new gene therapy that targets the genetic character of pancreatic cancer, using mutant adenoviruses that are selectively replication-competent in tumor cells. LOH of 30% or more was observed on chromosome arms 17p (47%), 9p (45%), 18q (43%), 12q (34%), and 6q (30%).