Evaluation of 18F-2-deoxy-2-fluoro-glucose positron emission tomography for gastric cancer screening in asymptomatic individuals undergoing endoscopy.

(18)F-2-deoxy-2-fluoro-glucose Positron Emission Tomography (FDG-PET) has been recently proposed as a promising cancer-screening test. However, the validity of FDG-PET in cancer screening has not been evaluated. We investigated the sensitivity of FDG-PET compared with upper gastric endoscopy in gastric cancer screening for asymptomatic individuals. A total of 2861 consecutive subjects (1600 men and 1261 women) who were asymptomatic and who underwent both FDG-PET and upper gastrointestinal endoscopy between 1 February 2004 and 31 January 2005 were included in this study. Both endoscopists and a radiologist were unaware of the results of the other diagnostic tests. The FDG-PET images were examined using criteria determined by the pattern of FDG accumulation. Sensitivity and specificity of FDG-PET were calculated compared with endoscopic diagnosis as the gold standard. Among 2861 subjects enrolled in the study, there were 20 subjects with gastric cancer, of whom 18 were T1 in depth of cancer invasion. Positive FDG-PET results were obtained only in 2 of the 20 cancer subjects. The calculated sensitivity and specificity for overall gastric cancers were 10.0% (95% confidence interval (CI): 1.2-31.7%) and 99.2% (95% CI: 98.8-99.5%), respectively. (18)F-2-deoxy-2-fluoro-glucose Positron Emission Tomography was poorly sensitive for detection of gastric cancer in the early stages.

Narrow-band imaging in the diagnosis of colorectal mucosal lesions: a pilot study.

BACKGROUND AND STUDY AIMS: A newly developed narrow-band imaging (NBI) technique, in which modified optical filters were used in the light source of a video endoscope system, was applied during colonoscopy in a clinical setting. This pilot study evaluated the clinical feasibility of the NBI system for evaluating colorectal lesions. PATIENTS AND METHODS: A total of 43 colorectal lesions in 34 patients were included in the study. The quality of visualization of colorectal lesions and the accuracy of differentiation between neoplastic and non-neoplastic lesions using the NBI system were evaluated in comparison with results from conventional colonoscopy and with chromoendoscopy. RESULTS: For pit pattern delineation, NBI was superior to conventional endoscopy (P < 0.001), but inferior to chromoendoscopy (P < 0.05). NBI achieved better visualization of the mucosal vascular network and of the hue of lesions than conventional endoscopy (P < 0.05). However there was no significant difference between NBI and chromoendoscopy in differentiating neoplastic from non-neoplastic lesions (both techniques had a sensitivity of 100 % and a specificity 75 %). This was better than the results of conventional colonoscopy (sensitivity 83 %, specificity 44 %; P < 0.05 for specificity). CONCLUSIONS: These results suggest that in the examination of colonic lesions the NBI system provides imaging features additional to those of both conventional endoscopy and chromoendoscopy. For distinguishing neoplasms from non-neoplastic lesions, NBI was equivalent to chromoendoscopy.

Development of an aggressive depressed cancer in a case of familial adenomatous polyposis.

In 1977, Kariya et al. reported a case of a small depressed cancer in a patient with familial adenomatous polyposis (FAP) raising the possibility that not all cancers in FAP develop from polypoid adenomas. It is now becoming widely recognized that colonic adenomas may appear as flat or depressed lesions. However, colorectal cancers developing in patients with familial adenomatous polyposis (FAP) are still thought to evolve from adenomatous polyps following the polyp-carcinoma sequence. We report the case of a patient with FAP in whom rectal carcinoma developed 23 years after subtotal colectomy and ileorectal anastomosis. We suggest that this malignancy may have developed de novo because of the depressed shape of the lesion and the aggressive growth pattern. This case raises the possibility that carcinomas may not always evolve from polyps in FAP. Aggressive cancers with a depressed appearance should be searched for when surveying the rectal stump in patients with FAP.

MTG8 proto-oncoprotein interacts with the regulatory subunit of type II cyclic AMP-dependent protein kinase in lymphocytes.

AML1-MTG8 chimeric oncogene is generated in acute myelogenous leukemia with t(8;21), and seems to be responsible for the pathogenesis of the disease. However, the role of MTG8 is ambiguous. Here we found that MTG8 interacted with the regulatory subunit of type II cyclic AMP-dependent protein kinase (PKA RIIalpha). The binding site of MTG8 was NHR3 domain, and that of RIIalpha was the N-terminus for interacting with PKA anchoring proteins (AKAPs). NHR3 contains a putative alpha-amphipathic helix which is characteristic in binding of AKAPs with RII. Indirect immunofluorescence microscopy showed that MTG8 and RIIalpha were overlapped at the centrosome-Golgi area in lymphocytes. These findings suggest that MTG8 may function as an AKAP at the centrosome-Golgi area in lymphocytes.

Endoscopic treatment for laterally spreading tumors in the colon.

BACKGROUND AND STUDY AIMS: Laterally spreading tumors (LST) of the colon are best removed by endoscopic mucosal resection (EMR) as they extend laterally rather than vertically. Since they sometimes invade deeply into the submucosal layer, it is important to assess the depth of invasion endoscopically before treatment. In the present study, we examined the endoscopic features of a large number of LSTs in order to assess which features correlated with depth of invasion. MATERIALS AND METHODS: 257 LSTs removed at the National Cancer Center Hospital, Tokyo, between January 1988 and September 1998 were retrospectively analyzed. RESULTS: With univariate analysis, unevenness of nodules, presence of large nodules, size, histological type, and presence of depression in the tumor were significantly associated with depth of invasion. Multivariate analysis revealed that histological type and depression in the tumor were independent factors predicting massive submucosal invasion. When an LST showed: 1) even nodules without depression, or 2) uneven nodules without depression and less than 3 mm in diameter, the risk of massive submucosal invasion was 0 % (0/121) and 3.7 % (3/82), respectively. CONCLUSION: When LSTs meet the above endoscopic criteria, EMR should be the first-line treatment because of the low risk of massive submucosal invasion.

[Helicobacter pylori & gastric disease].

Since the discovery of Helicobacter pylori(H. pylori), causal linkage between H. pylori infection and some of gastric disease has been generally accepted from the results of many studies. Indeed the usefulness of H. pylori eradication therapy for acute gastritis, peptic ulcer, gastric polyp and MALT lymphoma etc. has been reported. In the low grade MALT lymphoma, the regression rate by this therapy is about 70%. On the other hand, we should pay the caution to several adverse effects, such as drug resistance and GERD, of H. pylori eradication therapy. However, based on the several results of comparative studies between antibiotic therapy and the other one, the antibiotic therapy for peptic ulcer is only covered by national health insurance at present. The reversibility of gastric precancerous conditions such as mucosal atrophy, intestinal metaplasia and dysplasia by antibiotic therapy has been studied, but its significance is not clear yet. In animal experiment, H. pylori infection induced gastric adenocarcinoma in Mongolian Gerbils. However, this phenomenon is limited to this kind of animal only. To proof the causal link between H. pylori infection and genesis of gastric cancer in human being, clinical intervention trials are ongoing in the world. If these trials can clarify it, the H. pylori eradication therapy will be established as preventive measure for gastric carcinogenesis.

A novel tetracycline-dependent transactivator with E2F4 transcriptional activation domain.

A tetracycline-controlled gene expression system provides a powerful tool to dissect the functions of gene products. However, it often appears difficult to establish cell lines or transgenic animals stably expressing tetracycline-dependent transactivators, possibly as a result of toxicity of the transactivator domains used. In order to overcome this problem, we developed a novel tetracycline-dependent transactivator that works efficiently in mammalian cells. This transactivator is a fusion of the tet reverse repressor mutant and the transcriptional activating domain of human E2F4, which is ubiquitously expressed in vivo. We demonstrate here that this tetracycline-regulated gene expression system provides a two log transcriptional activation in mammalian cells as assessed by northern blot and luciferase analyses. Combining this system with green fluorescent protein reporter systems or microarray gene expression profiling will facilitate the study of gene function.

Endoscopically demonstrable esophageal changes after Helicobacter pylori eradication in patients with gastric disease.

BACKGROUND AND AIMS: An increased prevalence of reflux esophagitis has been reported following Helicobacter pylori (H. pylori) eradication in patients with duodenal ulcers in Western countries. However, it has remained unknown whether this might also appertain to individuals with other diseases. We therefore carried out this study to determine the effect of eradicating H. pylori infection in a series of Japanese patients. METHODS: Of a total of 203 H. pylori-positive patients successfully cured of infection, 82 cases (58 males, 24 females) with gastric disease, but not duodenal ulcers, were included in the present study; median age 56 years (range 18-80) and median follow up of 24 months (range 6-65). The patients were investigated clinically and endoscopically at regular intervals. RESULTS: Mild reflux esophagitis developed after eradication in three of 55 (5.5%) patients formerly without this condition, while it improved after eradication in five of 27 (18.5%) patients, with the disease endoscopically diagnosed prior to eradication. The estimated incidence of esophagitis within 3 years was 4.8% after cure of infection. Short segment Barrett's esophagus developed after eradication in six of 58 (10.3%) patients who did not have it prior to the therapy, while the condition did not improve in 24 patients affected before eradication. CONCLUSIONS: Endoscopic esophageal changes after H. pylori eradication in the present series of Japanese patients were relatively infrequent and mild. This therapeutic approach thus appears to be safe and unproblematic.

Induction of MTG8-specific cytotoxic T-cell lines: MTG8 is probably a tumour antigen that is recognized by cytotoxic T cells in AML1-MTG8-fused gene-positive acute myelogenous leukaemia.

Several reports have demonstrated the persistent detection of AML1-MTG8 fusion products, representing minimal residual disease (MRD), in patients with t(8;21) acute myelogenous leukaemia (AML) who are in long-term remission. It is probable that immune-mediated mechanisms that are able to suppress the expansion of MRD may result in the continuance of remission. It was previously shown that some t(8;21) AML patients had high anti-MTG8 antibody titres. MTG8 expression in normal adult tissues is limited to the brain or heart in which human leucocyte antigen (HLA) class I cell-surface antigens are either not or are only faintly detectable. We hypothesized that the overexpression of the MTG8 gene in t(8;21) AML cells could act as a possible tumour antigen, which might be able to induce the immune-mediated suppression of the expansion of MRD. We were able to induce HLA-A0201-restricted cytotoxic T-lymphocyte (CTL) lines against an MTG8 peptide (MTG8b amino acids 182-191) using monocyte-derived dendritic cells from a healthy donor. T-cell receptor (TCR)Valpha17, TCRVbeta14 and 15, and TCRJbeta2.1 and 2.3 are predominantly used in these CTL lines. Our data, which suggest that the MTG8 protein could be one of the tumour antigens recognized by CTLs, may be helpful in further investigations of TCR analysis in t(8;21) AML patients with HLA-A0201 who are in long-term remission.

Ribonuclease H attack of leukaemic fused transcripts AML1-MTG8 (ETO) by DNA/RNA chimeric hammerhead ribozymes.

BACKGROUND: Catalytic anti-sense oligonucleotides might be useful tools for controlling specific gene expression. However, to obtain effective oligonucleotides of the desired function in vivo is still a difficult task. RESULTS: To evaluate the usefulness of synthesized DNA/RNA hammerhead ribozymes targeting AML1-MTG8 (ETO) leukaemic fusion transcripts in vivo, we analysed their effects on cell growth and the mechanism of action using isolated cell nuclei. These ribozymes inhibited the growth of leukaemic cell lines expressing the AML1 -MTG8 and degraded AML1-MTG8 mRNA in isolated nuclei of these cells. However, the reactions gave rise to additional cleavage products. Systematic cleavage analyses using an anti-sense oligonucleotide array revealed that the cleavage was induced by endogenous RNase H at specific sites, in accordance with their calculated melting temperature (Tm) values. With suppression of RNase H by sulfhydryl agents, the DNA/RNA ribozyme had a ribozyme catalytic activity. In addition, the ribozymes and anti-sense oligonucleotides suppressed the AML1-MTG8 protein in the leukaemic cells. CONCLUSIONS: The DNA/RNA ribozymes inhibited cell growth primarily via anti-sense effects, the main role of which was the activation of RNase H-digestion by their DNA arms. In addition, the isolated nuclei provided a useful assay system for modelling in vivo conditions for the quantitative evaluation of anti-sense/ribozyme activity.

Heterogeneous nuclear ribonucleoprotein B1 as a new marker of early detection for human lung cancers.

Heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 is an RNA binding protein that is required for maturation of mRNA precursor. Tockman et al. previously reported that hnRNP A2/B1 with a M(r) of 31,000 is overexpressed from the early clinical stage of human lung cancer (M. S. Tockman et al., J. Clin. Oncol., 6: 1685-1693, 1988). However, when hnRNP A2/B1 mRNA and hnRNP B1 mRNA were separately studied, we found unique evidence that hnRNP B1 mRNA, which is a splicing variant of hnRNP A2 mRNA, was more significantly elevated in lung cancer tissues than hnRNP A2/B1 mRNA. Our hnRNP B1-specific polyclonal antibody specifically recognized hnRNP B1 protein as a M(r) 37,000 nuclear protein by Western blotting but did not recognize hnRNP A2 protein. Immunohistochemical staining with the hnRNP B1 antibody revealed that hnRNP B1 protein was specifically stained in the nuclei of human cancer cells, and in squamous cell carcinomas in particular, but not in those of normal adjacent lung epithelial cells. We think that hnRNP B1 protein of M(r) 37,000, not hnRNP A2, is well qualified as a biomarker for the detection of human lung cancer.

Association of MTG8 (ETO/CDR), a leukemia-related protein, with serine/threonine protein kinases and heat shock protein HSP90 in human hematopoietic cell lines.

A proto-oncogene, MTG8 (ETO/CDR), is disrupted in the t(8;21) translocation associated with acute myeloid leukemia, and the gene product, MTG8, is a phosphoprotein capable of cell transformation in concert with v-H-ras. To obtain insight into functional regulation of MTG8 by phosphorylation, we studied protein kinases that interact with, and phosphorylate, MTG8 in vitro. Recombinant MTG8 protein was first found to be associated with two serine/threonine protein kinases in cell extracts from both HEL cells and a leukemic cell line carrying t(8;21). A cytoplasmic protein kinase of 61 kDa (MTG8N-kinase) phosphorylated the amino-terminal of MTG8, and another of 52 kDa (MTG8C-kinase) phosphorylated the carboxyl-terminal domain. In addition, we demonstrated that heat shock protein 90 (HSP90) specifically binds to the amino-terminal domain of MTG8 in vitro and in vivo. Thus, our results shed new light on post-translational regulation of MTG8, perturbation of which, in AML1-MTG8 protein, probably contributes to leukemogenesis.

Tumourigenicity of MTG8, a leukaemia-related gene, in concert with v-Ha-ras gene in BALB/3T3 cells.

The MTG8 (ETO) gene has been identified as the translocation partner of AML1 (PEBP2alphaB or CBFalpha2) gene in the AML1/MTG8 (ETO) fused gene caused by t(8;21) translocation in human acute myeloid leukaemia, M2 type. Although AML1/MTG8 chimaeric protein is known to inhibit the functioning of AML1 protein, the precise function of MTG8 gene itself is not known yet. We studied the significance of MTG8 gene in the oncogenicity of AML1/MTG8 fused gene, by introducing full-length MTG8 cDNA into both BALB/3T3 cells containing v-Ha-ras gene (Bhas 42 cells) and BALB/3T3 cells without v-Ha-ras gene. Irrespective of the overexpression of MTG8 gene in both groups of cells, Bhas-MTG8 clones which contained v-Ha-ras gene and expressed the MTG8 gene at a level more than twice that of parental Bhas 42 cells induced cell transformation, whereas BALB-MTG8 clones without v-Ha-ras gene did not. Furthermore, injection of the transformed Bhas-MTG8 clones into the subcutaneous tissue of nude mice induced tumours, whereas that of BALB-MTG8 clones did not. These results suggest that MTG8 gene product, in cooperation with viral Ras protein, resulted in tumour formation. We provide the first evidence that MTG8 gene by itself has a carcinogenic property within the AML1/MTG8 (ETO) fused gene.

Cancer inhibition by green tea.

Green tea is now an acknowledged cancer preventive in Japan. This paper discusses several important features of (-)-epigallocatechin gallate (EGCG), the main constituent of green tea and tea polyphenols. EGCG and other tea polyphenols inhibited growth of human lung cancer cell line, PC-9 cells with G2/M arrest. 3H-EGCG administered by p.o. intubation into mouse stomach revealed that small amounts of 3H-activity were found in various organs where EGCG and green tea extract had previously demonstrated their anticarcinogenic effects, such as skin, stomach, duodenum, colon, liver, lung and pancreas. Cancer onset of patients who had consumed over 10 cups of green tea per day was 8.7 years later among females and 3.0 years later among males, compared with patients who had consumed under three cups per day. The mechanisms of action of EGCG were briefly discussed with regard to inhibition of tumor necrosis factor-alpha (TNF-alpha) release.

Cooperative Clinical Trial of Photodynamic Therapy for Early Gastric Cancer With Photofrin Injection and YAG-OPO Laser.

BACKGROUND AND OBJECTIVE: Photodynamic therapy (PDT) treats malignant tumors using photosensitizers and light. We employed a new pulse laser as the excitation light source for PDT, i.e. an optical parametric oscillator (OPO) system pumped by a Q-switched Nd:YAG laser, because it provides extremely high peak power. STUDY DESIGN/MATERIALS AND METHODS: The effects of PDT using the photosensitizer Photofrin((R)) and the new laser were evaluated in 12 patients with early gastric cancer. RESULTS: Complete responses (CR) were obtained in 75% of 12 assessable patients, CR was observed in all cases with mucosal carcinoma (response rate 100%).Regarding toxicity, mild photosensitivity was seen in one case and it lasted several weeks. The other major side effect was decrease of total protein, which was observed in six patients (40%), lasting several months. There were no serious abnormalities in symptoms or laboratory tests. CONCLUSION: We conclude that the YAG-OPO laser is suitable as an excitation light source for PDT.

A Clinical Study of Photodynamic Therapy for Superficial Esophageal Carcinoma by YAG-OPO Laser.

A cooperative clinical study of photodynamic therapy (PDT) for superficial esophageal carcinoma was conducted at 6 medical institution. PHE (2mg/kg) with high tumor affinity was used as the oncotropic compound. The light source was a pulse wave YAG-OPO laser with high penetration into the tissue. Irradiation was performed at an energy density of 60-180 J/cm(2) 48-72 h after PHE administration. Eight lesions in 6 patients were treated. All were type 0-II superficial carcinomas. The depth of invasion was EP-MM for 6 lesions and SM for 2 lesions. A complete response (CR) was achieved in all patients after one session of PDT. Five adverse events, including anemia and fever, were reported by 4 patients, but all were WHO grade 2 or lower and transient. PDT using PHE and YAG-OPO laser was therefore considered effective as a curative therapy for superficial esophageal carcinoma.

Embryological fusion between the ducts of the ventral and dorsal primordia of the pancreas occurs in two manners.

The junction between the main pancreatic duct and the accessory duct has been thought to be the site of fusion between the ducts of the ventral and the dorsal primordia of the pancreas. The aim of this study was to investigate the fusion point between the ventral and the dorsal pancreatic ducts and to determine whether there is any relationship between the configuration of the pancreatic ducts and the manner of embryological fusion. Pancreatography was performed at 22 consecutive autopsies. Immunohistochemical staining of pancreatic polypeptide (PP) was performed because PP cells were rich in the ventral pancreas but poor in the dorsal pancreas. We identified two types of fusion. In one type, the ventral and the dorsal pancreatic ducts fuse at their junction (one-point fusion). In the other type, the two ducts fuse not only at the proximal site but at a second, more distal site (two-point fusion). Analysis of the pancreatograms showed that the distance between the junction and the major papilla in two-point fusion is significantly shorter than in one-point fusion (p < 0.01). These results indicate a close correlation between the pattern seen on pancreatograms and the manner of embryological fusion.

Significance of MTG8 in leukemogenesis.

MTG8 is a counterpart gene of AML1 in acute myeloid leukemia with t(8:21) translocation. Most of the coding region of the MTG8 is fused with AML1 runt domain. In normal tissues, the MTG8 is highly expressed in brain, but not in hematopoietic tissues. MTG8 may be important in leukemogenesis as well as in AML1 truncation. The function of MTG8 is assumed to be as a transcription factor, because it possesses several features common to transcription factors; putative zinc finger motifs, serine/threonine/proline-rich sequences and a region similar to TAF110. In this paper, we report on the protein properties of the MTG8.