Neuroendocrine tumors including carcinoid tumors and pancreatic endocrine tumors are uncommon, and the genetic alterations in these indolent tumors are not well characterized. We studied global hypomethylation by analyzing long interspersed nucleotide elements (LINE)-1 and Alu methylation using pyrosequencing in 35 neuroendocrine tumors and corresponding normal tissue. The tumor samples were less methylated than normal tissue at LINE-1 (P ¼ 0.04) and Alu (P ¼ 0.001). The mean relative tumor hypomethylation (difference in methylation between normal tissue and in tumor) was 11.5710.0 for LINE-1 and 5.876.4 for Alu, and were correlated with each other (correlation coefficient 0.6, P ¼ 0.001). Relative tumor hypomethylation of LINE-1 was higher in ileal carcinoid tumors than in non-ileal carcinoid tumors and pancreatic endocrine tumors (P ¼ 0.047), and tumors with lymph node metastasis (P ¼ 0.02), chromosome 18 loss (P ¼ 0.001) and RAS-association domain family 1, isoform A gene methylation (P ¼ 0.02). Alu methylation in tumors was inversely correlated with methylation of O 6 -methyl-guanine methyltransferase gene (P ¼ 0.02). Our study shows that hypomethylation is more common in carcinoid tumors than in pancreatic endocrine tumors and is associated with clinicopathologic features, and genetic and epigenetic alterations in these tumors, including lymph node metastasis.

Endoscopic enucleation of gastric SETs originating in the muscularis propria layer was a safe and effective method for the histologic diagnosis and removal of small gastric SETs, especially those located in the cardia and the high body of the stomach.

Transabdominal US-guided pancreatic core biopsy may not provide enough tissue to evaluate characteristic histopathologic features of AIP that include LPSP or abundant IgG4-positive cell infiltration. The LPSP histology may be specific to AIP, but abundant IgG4-positive cells in the pancreas may not.

Well-differentiated neuroendocrine tumors (WDNT, carcinoid tumors) are uncommon indolent neoplasms. The genetic alterations of these tumors are not well characterized. We used genome-wide high-density single nucleotide polymorphism (SNP) array analysis to detect copy number alterations in 29 WDNTs, including seven lung, seven nonileal gastrointestinal, and 15 ileal tumors, and compared with allelic imbalances in 15 pancreatic endocrine tumors (PETs). Most frequent allelic imbalances in WDNTs were losses of chromosome 18 in 10 tumors (34%), chromosome 21 or 21q in six (21%), chromosome 13 or 13q in five (17%) and chromosome 16 or 16q in four (14%) tumors, and amplification of chromosome 20 or 20p in seven (24%) tumors. We also found one tumor with loss of heterozygosity of chromosomes 10 and 15 without copy number loss. These allelic imbalances were associated with primary site of tumor: loss of chromosome 18 was present exclusively in ileal WDNTs (P 5 0.001), and loss of chromosome 21 or 21q was more frequent in nonileal gastrointestinal WDNTs (P 5 0.02). The tumors with loss of chromosome 21 were larger compared to tumors without loss (P 5 0.03). Chromosomal aberrations were less common in WDNTs from lung and gastrointestinal tract compared to PETs (P 5 0.001). Our study shows that genome-wide allelotyping using SNP array is a powerful new tool for the analysis of allelic imbalances in WDNTs, and some of these alterations are tumor site-dependent and are different than in PETs. V V C 2007 Wiley-Liss, Inc.

Cisplatin is a chemotherapeutic agent that is widely used to treat cancers such as head and neck squamous cell carcinoma (HNSCC). Previously, we have reported that cisplatin induced an early caspase-dependent apoptosis (8 hr) in a HNSCC cell, HN4. In this study, we examined a late caspase-independent apoptosis as well as an early caspase-dependent apoptosis in cisplatintreated HN4 cells. While z-VAD-fmk, a pan-caspase inhibitor, blocked the caspase activities and protected cells from the early apoptosis, it did not provide protection against delayed apoptosis occurring after extended exposure (16 hr) to cisplatin, suggesting that the delayed apoptotic response in the presence of z-VAD-fmk was caspase-independent. Cisplatin treatment induced reactive oxygen species (ROS) generation, loss of the mitochondrial membrane potential (MMP) and nuclear translocation of endonuclease G (EndoG). Small interfering RNA mediated-knockdown of EndoG significantly protected cells from the delayed apoptosis induced by cisplatin in the presence of z-VAD-fmk. Overexpression of Bcl-2 in HN4 cells prevented loss of MMP, nuclear translocation of EndoG and protected cells from the delayed apoptosis induced by cisplatin in the presence of z-VAD-fmk. Pretreatment with N-acetyl-L-cysteine (NAC), a ROS scavenger, prevented both ROS generation, loss of the MMP and nuclear translocation of EndoG. Together, our data indicate that cisplatin treatment induced ROS-mediated loss of the MMP, and, then, the nuclear translocation of EndoG, which played a crucial role in caspase-independent apoptosis of HN4 cells in the presence of z-VAD-fmk. This is the first report about the involvement of EndoG in cisplatin-induced caspase-independent apoptosis of cells. ' 2007 Wiley-Liss, Inc.

Pancreatic endocrine tumors (PETs) are uncommon and the genetic alterations in these indolent tumors are not well characterized. Chromosomal imbalances are frequent in tumors but PETs have not been studied by high-density single nucleotide polymorphism (SNP) array. We used genome-wide high-density SNP array analysis to detect copy number alterations using matched tumor and non-neoplastic tissue samples from 15 patients with PETs. In our study, whole or partial loss of chromosomes 1, 3, 11, 22 was present in 40, 47, 53, 40% of tumors respectively, and gain of chromosomes 5, 7, 12, 14, 17, and 20 was present in 47, 60, 47, 53, 53, and 47% of tumors respectively. One tumor had loss of heterozygosity of chromosome 3 and another of chromosome 22 without copy number alterations, suggesting uniparental disomy due to non-disjunction and deletion or to chromosomal recombination. Chromosomal aberrations of the autosomal chromosomes were correlated with chromosomal loss or gain of other chromosomes (rO0.5, P!0.5). About 60% of PETs had high allelic imbalances (AI) defined by more than four chromosomal aberrations, and 40% of tumors had low AI. The PETs with high AI were larger: the mean tumor size with high AI was 5.4G3.1 cm compared with 2.3G1.3 cm for low AI (PZ0.03). Our study shows that genome-wide allelotyping is a powerful new tool for the analysis of AI in PETs.

Gastrointestinal stromal tumor (GIST) represents the most common kind of mesenchymal tumor that arises from the alimentary tract. GIST is currently defined as a gastrointestinal tract mesenchymal tumor showing CD117 (c-kit protein) positivity at immunohistochemistry. Throughout the whole length of the gastrointestinal tract, GIST arises most commonly from the stomach followed by the small intestine, the colorectum, and the esophagus. Only 3%-5% of GISTs occur in the duodenum, and especially, if GIST arises from the C loop of the duodenum, it can be difficult to differentiate from the pancreas head mass because of its anatomical proximity. Here, we report a case of duodenal GIST, which was assessed as a pancreatic head tumor preoperatively.

A duodenal duplication cyst is an uncommon congenital anomaly that is usually encountered during infancy or in early childhood. Duodenal duplication cysts generally appear on the first or second portion of the duodenum and may cause duodenal obstruction, hemorrhage or pancreatitis. Here, we report a case of a duodenal duplication cyst on the second and third portion of the duodenum in an old aged man with obstructive jaundice and acute pancreatitis, which was treated successfully by a surgical excision.