Takao Endo

Detection of hypermethylation of the p16 INK4A gene promoter in chronic hepatitis and cirrhosis associated with hepatitis B or C virus

BACKGROUND/AIM Inactivation of the p16 INK4A(p16) tumour suppressor gene by promoter region hypermethylation has been demonstrated not only in many types of tumours, including hepatocellular carcinoma (HCC), but also in early preneoplastic lesions in the lung, colon, oesophagus, and pancreas. The aim of this study was to examine the methylation status of thep16 promoter in pre- and/or non-neoplastic liver diseases. PATIENTS/SUBJECTS/METHODS The methylation status of p16 was evaluated in 22 HCC, 17 cirrhosis, 17 chronic hepatitis, nine primary biliary cirrhosis (PBC), eight autoimmune hepatitis, seven drug induced liver disease, six fatty liver, and three normal liver tissues using methylation specific polymerase chain reaction (MSP). p16 protein expression was also examined by immunohistochemical staining. RESULTS Methylation of the p16 promoter was detected in HCC (72.7%, 16/22) and also in cirrhosis (29.4%, 5/17) and chronic hepatitis (23.5%, 4/17), all of which were positive for hepatitis B or C virus infections. Methylation was not detected in any of the other samples. All methylation positive HCC, cirrhosis, and chronic hepatitis samples showed loss of p16 expression, and a significant correlation was found between methylation and loss of expression. Analysis of serial samples from individual patients with methylation positive HCC revealed that loss of p16 expression with promoter methylation occurred in 18 of 20 patients at the stage of chronic hepatitis without clinically detectable carcinoma. CONCLUSIONS Our results suggest that methylation of the p16promoter and the resulting loss of p16 protein expression are early events in a subset of hepatocarcinogenesis and that their detection is useful in the follow up of patients with a high risk of developing HCC, such as those with hepatitis B or C viral infections.

MEK/ERK pathway protects ionizing radiation-induced loss of mitochondrial membrane potential and cell death in lymphocytic leukemia cells

MEK/ERK-mediated signals have recently been found to inhibit Fas-mediated cell death through inhibition of caspase-8 activity. It remains unknown whether MEK/ERK-mediated signals affect ionizing radiation (IR)-induced cell death. Here we demonstrate that MEK/ERK-mediated signals selectively inhibit IR-induced loss of mitochondrial membrane potential (ΔΨm) and subsequent cell death. In Jurkat cells, TPA strongly activated ERK and inhibited the IR-induced caspase-8/Bid cleavage and the loss of ΔΨm. The inhibitory effect of TPA was mostly abrogated by pretreatment of a specific MEK inhibitor PD98059, indicating that the effect depends upon MEK/ERK-mediated signals. Moreover, BAF-B03 transfectants expressing IL-2 receptor (IL-2R) βc chain lacking the acidic region, which is responsible for MEK/ERK-mediated signals, revealed higher sensitivity to IR than the transfectants expressing wild-type IL-2R. Interestingly, the signals could neither protect the ΔΨm loss nor cell death in UV-irradiated cells. These data imply that the anti-apoptotic effect of MEK/ERK-mediated signals appears to selectively inhibit the IR-induced cell death through protection of the ΔΨm loss. Our data enlighten an anti-apoptotic function of MEK/ERK pathway against IR-induced apoptosis, thereby implying its contribution to radioresistance.

Carcinoma of duodenum arising from Brunner's gland

Primary carcinoma of the duodenum is a rare lesion. In conjunction with the widespread use of panendoscopy, reported cases of carcinoma of the duodenum have recently increased. Although benign hyperplasia of Brunners gland is well documented, duodenal carcinoma originating in Brunners gland is extremely rare, and, consequently, there is little data on the morphological or histochemical characteristics. We report here a case of early duodenal carcinoma arising from Brunners gland, whose origin was proven by mucin immunohistochemistry.

The Antisense Approach in Amyloid Light Chain Amyloidosis: Identification of Monoclonal Ig and Inhibition of Its Production by Antisense Oligonucleotides in In Vitro and In Vivo Models

Primary amyloid L chain (AL) amyloidosis is a plasma cell disorder in which depositions of AL cause progressive organ failure. The lack of effective therapies for this fatal disease prompts exploration of newer treatment avenues. We have investigated the application of antisense oligonucleotides (AS) for the inhibition of monoclonal Ig production. The monoclonal L chain was identified by using primers designed for amplifying the human λ Ig V (Vλ) region. We demonstrated that AS against L chain complementarity-determining regions inhibited the production of L chain in vitro. RPMI 8226 myeloma cells injected in SCID mice developed s.c. tumors. RT-PCR analysis showed Vλ mRNA expression in the tumors. In addition, the presence of human Ig in the sera of mice given injection of RPMI 8226 cells was confirmed by ELISA. Administration of AS inhibited the expression of Vλ mRNA in the s.c. tumors and decreased the concentration of L chain in serum. Therefore, we have shown that it is possible to determine the sequence of Vλ mRNA and design specific complementary oligonucleotides, suggesting that treatment with Vλ antisense could represent a rational novel approach to improve treatment outcome in AL amyloidosis.

Mucin phenotype and microsatellite instability in early multiple gastric cancers.

Clinicopathologically, multiple gastric cancers (MGCs) are reported to involve predominantly intestinal‐type adenocarcinoma and frequently to be associated with severe intestinal metaplasia. However, there are few reports concerning the characteristic biomarkers of early MGCs. The aim of our study was to identify the cellular lineage defined by mucin phenotypes and the relationships among mucin phenotypes, background mucosa and microsatellite instability (MSI) of early MGCs. We examined mucin phenotypes of 63 surgically resected carcinomas from 25 patients with early MGCs and 39 early solitary gastric cancers (SGCs) by immunohistochemical analysis using a panel of monoclonal antibodies. MSI and the degree of intestinal metaplasia (IM) on the background mucosa were also examined. In early MGCs, the incidence of cancer exhibiting the gastric phenotype (G‐type) was 59% (37 of 63 cancers), which was higher than that in early SGCs (23%, 9 of 39 cancers). There was a significant difference between the distributions of mucin phenotypes in early MGCs and early SGCs (p = 0.001). Whereas half of the G‐type cancers in early MGCs were related to severe IM, none of the G‐type cancers in early SGCs were related to severe IM. In the early MGCs, MSI was observed in 21 of 63 cancers (33.3%). In contrast, MSI was observed in only 3 of the 39 (7.7%) early SGCs, indicating a significant difference between these 2 groups (p < 0.01). Our results suggest that the characteristic features of early MGCs are the gastric mucin dominant phenotype and high frequency of MSI.

Jejunal carcinoid tumor mimicking leiomyosarcoma: preoperative diagnosis by endoscopic biopsy

Abstract: Primary carcinoid tumor of the jejunum is rare, and is an unusual cause of massive gastrointestinal bleeding. A case of primary jejunal carcinoid tumor in a 39-year-old woman who presented with massive hematochezia is described. Both upper and lower gastrointestinal endoscopies showed no abnormalities. An abdominal computed tomographic scan, small-bowel barium contrast studies, and small-bowel endoscopy showed a subserosal mass, of 5 × 4 cm, with a cavity suggesting central necrosis, and a deep mucosal ulceration, located in the proximal jejunum. Although these clinical presentations were strongly suggestive of a leiomyosarcoma, histologic examination of biopsy samples obtained by enteroscopy confirmed the diagnosis of jejunal carcinoid tumor. The patient underwent radical jejunal resection and recovered uneventfully. In spite of the large size of the tumor, there was one solitary lymph node metastasis, but no evidence of liver metastases. This kind of jejunal carcinoid tumor, presenting with massive gastrointestinal bleeding and a subserosal bulky growth mimicking a leiomyosarcoma, has not been reported previously. Moreover, this is a rare case of a jejunal carcinoid which was diagnosed preoperatively by small bowel-endoscopic biopsy.

Distribution of secretory component in noncancerous human gastric mucosa

SummaryImmunological detection of secretory component (SC) in non-cancerous human gastric mucosa was carried out by the peroxidase-anti-peroxidase (PAP) method using several fixatives. SC was detected in the generative zone or mucous neck of normal gastric mucosa without intestinal metaplasia (IM) and in absorptive cells of IM of the stomach. The deep part of complete type IM showed a larger amount of SC than the superficial part. These findings suggested that the appearance of SC in gastric mucosa would be relevant to the immunity of glandular epithelium. In addition, SC was also detected in pyloric gland cells in specimens fixed with cold 95% ethanol.From these results, SC was considered to be a normal constituent and one of the developmental proteins in the gastric mucosa.