Mesothelial cells with mesenchymal features enhance peritoneal dissemination by forming a protumorigenic microenvironment

Malignant ascites accompanied by peritoneal dissemination contain various factors and cell populations as well as cancer cells; however, how the tumor microenvironment is shaped in ascites remains unclear. Single-cell proteomic profiling and a comprehensive proteomic analysis are conducted to comprehensively characterize malignant ascites. Here, we find defects in immune effectors along with immunosuppressive cell accumulation in ascites of patients with gastric cancer (GC) and identify five distinct subpopulations of CD45(-)/EpCAM(-) cells. Mesothelial cells with mesenchymal features in CD45(-)/EpCAM(-) cells are the predominant source of chemokines involved in immunosuppressive myeloid cell (IMC) recruitment. Moreover, mesothelial-mesenchymal transition (MMT)-induced mesothelial cells strongly express extracellular matrix (ECM)-related genes, including tenascin-C (TNC), enhancing metastatic colonization. These findings highlight the definite roles of the mesenchymal cell population in the development of a protumorigenic microenvironment to promote peritoneal dissemination.

Hemodynamic Variability During Drainage of Large Volumes of Malignant Ascites in Patients With Cancer

This study compared the variability in mean arterial pressure (MAP) during drainage of ascites in patients with cancer who underwent drainage of a large (5-10 L) or small (<5 L) volume of ascites. We prospectively enrolled 50 patients scheduled for cell-free and concentrated ascites reinfusion therapy. Equivalence was considered to be established if the 95% confidence interval (95% CI) for the highest variability rate of MAP was within ±20%. The median volume of ascites removed was 3.30 L (95% CI [2.84, 4.40]) in the small-drainage-volume group (n = 15) and 6.75 L (95% CI [6.40, 7.30]) in the large-drainage-volume group (n = 34). The 95% CIs for the highest variability rates in MAP ranged from -19.60 to -6.23 and from -19.16 to -12.95 (p = .594), respectively, indicating equivalence. These findings indicate that variability in MAP during drainage of ascites is not dependent on drainage volume.

Proteomic Analysis of Malignant Ascites From Patients With Pancreatic Ductal Adenocarcinoma

BACKGROUND/AIM

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignant tumor. Research using an innovative research approach is needed to identify effective biomarkers or therapeutic targets for PDAC. We aimed to identify proteins related to the peritoneal dissemination of PDAC.

MATERIALS AND METHODS

We performed proteomic analysis using ascites samples from patients with advanced PDAC and peritoneal dissemination and patients with liver cirrhosis (LC). Proteins specific to PDAC were identified in comparison to the findings for ascites from patients with LC as a control group.

RESULTS

In total, 336 proteins were identified in ascites from patients with PDAC. We identified 18 specific proteins in ascites from patients with advanced PDAC. Among these proteins, CD13, lymphatic vessel endothelial hyaluronan receptor 1, ficolin-3, and V-set and immunoglobulin domain containing 4 were the most frequently detected. In addition, these 18 proteins could be classified into four categories: extracellular matrix, immunity, metabolism, and others.

CONCLUSION

The identified proteins could be informative for developing treatment strategies for patients with PDAC and peritoneal dissemination.

Large-volume cell-free and concentrated ascites reinfusion therapy improves venous flow in patients with liver cirrhosis

PURPOSE

Hemodynamic change after total paracentesis was investigated because it might lead to various complications. Although cell-free and concentrated ascites reinfusion therapy (CART) is safer and more effective than total paracentesis in theory, hemodynamic change after CART has been never reported. And previous studies did not mention hemodynamics of the venous system.

METHODS

We investigated the hemodynamic change, including that of the venous system, before and after CART using color Doppler ultrasonography and fast Fourier transform analysis. Twenty-eight patients with tensive cirrhotic ascites underwent ultrasonography the day before and after total volume CART. The diameter and velocity of the main, right, and left portal vein; inferior vena cava (IVC); and right renal vein were measured using ultrasonography.

RESULTS

A total of 11.8 ± 4.4 L of ascites (range 3.6-20.9 L) was filtered and concentrated to 0.85 ± 0.40 L (range 0.36-1.50 L). The diameter of the IVC increased from median 13.5 ± 5.4 mm (range 4-25 mm) to 18.5 ± 4.1 mm (range 7-29 mm) (p = 0.007). The diameter of the right segmental renal vein significantly increased after KM-CART [from 5.0 ± 1.0 (4-8) mm to 7.0 ± 2.0 (3-10) mm] (p = 0.011). Hemodynamic change of the portal venous system was not significant. The time to the next CART in patients with an IVC diameter ≥ 20 mm and < 20 mm was 86 days and 20.5 days (p = 0.035), respectively.

CONCLUSION

Tensive ascites results in venous congestion in patients with cirrhotic ascites. CART improved venous flow, but it did not change the hemodynamics of the portal venous system.

Inflammation-driven senescence-associated secretory phenotype in cancer-associated fibroblasts enhances peritoneal dissemination

In the tumor microenvironment, senescent non-malignant cells, including cancer-associated fibroblasts (CAFs), exhibit a secretory profile under stress conditions; this senescence-associated secretory phenotype (SASP) leads to cancer progression and chemoresistance. However, the role of senescent CAFs in metastatic lesions and the molecular mechanism of inflammation-related SASP induction are not well understood. We show that pro-inflammatory cytokine-driven EZH2 downregulation maintains the SASP by demethylating H3K27me3 marks in CAFs and enhances peritoneal tumor formation of gastric cancer (GC) through JAK/STAT3 signaling in a mouse model. A JAK/STAT3 inhibitor blocks the increase in GC cell viability induced by senescent CAFs and peritoneal tumor formation. Single-cell mass cytometry revealed that fibroblasts exist in the ascites of GC patients with peritoneal dissemination, and the fibroblast population shows p16 expression and SASP factors at high levels. These findings provide insights into the inflammation-related SASP maintenance by histone modification and the role of senescent CAFs in GC peritoneal dissemination.

In-vitro proliferation assay with recycled ascitic cancer cells in malignant pleural mesothelioma: A case report

BACKGROUND

We report the first case, to the best of our knowledge, of massive ascites due to recurrent malignant pleural mesothelioma that was controlled using KM-cell-free and concentrated ascites reinfusion therapy (KM-CART). The tumor cells derived via KM-CART were utilized secondarily in an in vitro cell growth assay using the collagen gel droplet-embedded culture drug sensitivity test (CD-DST) to investigate anticancer drug susceptibility.

CASE SUMMARY

A 56-year-old man presented with recurrent malignant mesothelioma with massive ascites; more than 4000 mL of ascitic fluid was removed, filtered, and concentrated using KM-CART, and the cell-free ascitic fluid was reinfused into the patient to improve quality of life. Cancer cells isolated secondarily in an in vitro proliferation assay using CD-DST exhibited low sensitivity to pemetrexed and high sensitivity to gemcitabine. Treatment with gemcitabine maintained stable disease for 4 mo.

CONCLUSION

The combination of KM-CART and CD-DST may be a promising treatment option for malignant ascites associated with malignant mesothelioma.

Efficacy of glutathione inhibitors for the treatment of ARID1A-deficient diffuse-type gastric cancers

ARID1A, a subunit of the SWI/SNF chromatin remodeling complex, increases the intracellular levels of glutathione (GSH) by upregulating solute carrier family 7 member 11 (SLC7A11). Diffuse-type gastric cancer is an aggressive tumor that is frequently associated with ARID1A deficiency. Here, we investigated the efficacy of GSH inhibition for the treatment of diffuse-type gastric cancer with ARID1A deficiency using ARID1A-proficient or -deficient patient-derived cells (PDCs). ARID1A-deficient PDCs were selectively sensitive to the GSH inhibitor APR-246, the GCLC inhibitor buthionine sulfoximine, and the SLC7A11 inhibitor erastin. Expression of SLC7A11, which is required for incorporation of cystine, and the basal level of GSH were lower in ARID1A-deficient than in ARID1A-proficient PDCs. Treatment with APR-246 decreased intracellular GSH levels, leading to the excessive production of reactive oxygen species (ROS), and these phenotypes are suppressed by supply of cystine and GSH compensators. Taken together, vulnerability of ARID1A-deficient gastric cancer cells to GSH inhibition is caused by decreased GSH synthesis due to diminished SLC7A11 expression. The present results suggest that GSH inhibition is a promising strategy for the treatment of diffuse-type gastric cancers with ARID1A deficiency.

[Usefulness of Peripherally Inserted Central Venous Catheters for Cancer Patients in Palliative Care Settings]

Peripherally inserted central venous catheters(PICCs)are widely used given they have lower incidence of serious complications than central venous catheters. We evaluated the safety and usefulness of ultrasound-guided PICC placement for cancer patients in palliative care settings. We attempted to insert PICCs in 42 patients, and the insertion was successful in 40 (95.2%)patients. Complications occurred in 9(22.5%)patients, but none were severe. In 30 cases, PICCs were used for infusion and drug delivery until cancer death. The duration of catheterization was 25(1-126)days. Our results suggest that ultrasound-guided PICC represents a safe and usefultoolfor cancer patients in palliative care settings.

A Tumor-targeting Adenovirus with High Gene-transduction Efficiency for Primary Pancreatic Cancer and Ascites Cells

BACKGROUND

Optimizing targeting strategies for vectors in order to enhance antitumor activity and secure patient safety is important for cancer gene therapy. We previously identified two pancreatic cancer-targeting ligands (PFWSGAV: PFW and SYENFSA: SYE) by screening an adenovirus library in vivo and in vitro, respectively.

MATERIALS AND METHODS

To examine clinical usefulness, we assessed gene-transduction efficiency using surgically-resected pancreatic cancer specimens and ascites cells.

RESULTS

For surgical specimens, vectors displaying PFW and SYE improved transduction efficiency by 4.4- and 4.3-fold, respectively. The SYE-displaying vector was >2-fold more efficient for all seven cases, whereas the PFW-displaying vector increased efficiency in two out of four cases. For ascites samples, both vectors increased gene-transduction efficiency of epithelial cell adhesion molecule (EpCAM)-positive ascites cells by >2-fold in two out of five cases.

CONCLUSION

Both vectors enhanced adenovirus infectivity of pancreatic cancer cells and have potential for gene therapy of pancreatic cancer; therefore they should be further evaluated in clinical studies.

Analysis of glycero-lysophospholipids in gastric cancerous ascites

Lysophosphatidic acid (LysoPA) has been proposed to be involved in the pathogenesis of various cancers. Moreover, glycero-lysophospholipids (glycero-LysoPLs) other than LysoPA are now emerging as novel lipid mediators. Therefore, we aimed to elucidate the possible involvement of glycero-LysoPLs in the pathogenesis of gastric cancer by measuring glycero-LysoPLs, autotaxin (ATX), and phosphatidylserine-specific phospholipase A1 (PS-PLA₁) in ascites obtained from patients with gastric cancer and those with cirrhosis (as a control). We observed that after adjustments according to the albumin levels, the lysophosphatidylserine (LysoPS) and lysophosphatidylglycerol (LysoPG) levels were significantly higher, while the LysoPA and ATX levels were lower, in the ascites from patients with gastric cancer. We also found that multiple regression analyses revealed that ATX was selected as a significant explanatory factor for all the detectable LysoPA species only in the cirrhosis group and that a significant positive correlation was observed between LysoPS and PS-PLA₁ only in the gastric cancer group. In conclusion, the LysoPA levels might be determined largely by LysoPC and LysoPI (possible precursors) and the PS-PLA₁-mediated pathway might be involved in the production of LysoPS in gastric cancer. Glycero-LysoPLs other than LysoPA might also be involved in the pathogenesis of cancer directly or through being converted into LysoPA.

[A New Treatment Strategy-Novel Cell-Free and Concentrated Ascites Reinfusion System(KM-CART)for Massive Malignant Ascites]

Massive ascites associated with cancerous peritonitis can result in severe respiratory discomfort and abdominal fullness. Additionally, it can significantly impair the activities of daily living of a patient, and relaxation is difficult to achieve, even with opioids. Frequent ascites drainage can cause rapid worsening of the patient's general condition, and a large amount of ascites can lead to discontinuation of anti-cancer treatment. Cell-free and concentrated ascites reinfusion therapy(CART)for refractory ascites was first covered by the insurance system in 1981. However, cancerous ascites includes many cellular components as well as mucus, and purification was a difficult process. Therefore, since the 1990s, CART disappeared from the field of cancer treatment. I have devised a Keisuke Matsusaki(KM)-CART system that has the ability to clean the filtration membrane. This system enables purification of massive cancerous ascites that may exceed 20 L. The general condition of the patients and their symptoms improve after use of KM-CART, making it possible to initiate or resume anti-cancer therapy. KM-CART helps remove unwanted components, such as cancer cells, cytokines, and vascular endothelial growth factors from the abdominal cavity through filtration of drained ascites. Therefore, the peritoneal environment can be improved, leading to enhancement of the efficacy of intraperitoneal chemotherapy. In addition, a large number of cancer cells and lymphocytes can be obtained with KM-CART, and it is possible to use these cells for customized cancer treatments, such as dendritic cell vaccine therapy, and to perform anti-cancer agent susceptibility testing. I believe that KM-CART is a good treatment approach for massive ascites associated with cancerous peritonitis.

Overexpression of KIF11 in Gastric Cancer with Intestinal Mucin Phenotype

OBJECTIVE

Gastric cancer (GC) is one of the most common human cancers. A useful method of gastric cancer stem cell (CSC) characterization is spheroid colony formation. Previously, we reported that KIF11 expression is >2-fold in spheroid-body-forming GC cells compared with parental cells. Here, we analyzed the expression and distribution of KIF11 in human GC by immunohistochemistry.

METHODS

Expression of KIF11 in 165 GC cases was determined using immunohistochemistry. For mucin phenotypic expression analysis of GC, immunostaining of MUC5AC, MUC6, MUC2 and CD10 was evaluated. RNA interference was used to inhibit KIF11 expression in GC cell lines.

RESULTS

In total, 119 of 165 GC cases (72%) were positive for KIF11. Expression of KIF11 was not associated with any clinicopathologic characteristics; however, it was observed frequently in GC exhibiting an intestinal phenotype. Both the number and size of spheres formed by MKN-74 cells were significantly reduced following transfection of KIF11-targeting siRNA compared with negative-control siRNA. Furthermore, levels of phosphorylated Erk1/2 were lower in KIF11 siRNA-transfected cells than with negative-control siRNA-transfected cells.

CONCLUSION

These results indicate that KIF11 is involved in intestinal mucin phenotype GC.

Identification and Characterization of CXCR4-Positive Gastric Cancer Stem Cells

Diffuse-type solid tumors are often composed of a high proportion of rarely proliferating (i.e., dormant) cancer cells, strongly indicating the involvement of cancer stem cells (CSCs) Although diffuse-type gastric cancer (GC) patients have a poor prognosis due to high-frequent development of peritoneal dissemination (PD), it is limited knowledge that the PD-associated CSCs and efficacy of CSC-targeting therapy in diffuse-type GC. In this study, we established highly metastatic GC cell lines by in vivo selection designed for the enrichment of PD-associated GC cells. By microarray analysis, we found C-X-C chemokine receptor type 4 (CXCR4) can be a novel marker for highly metastatic CSCs, since CXCR4-positive cells can grow anchorage-independently, initiate tumors in mice, be resistant to cytotoxic drug, and produce differentiated daughter cells. In clinical samples, these CXCR4-positive cells were found from not only late metastasis stage (accumulated ascites) but also earlier stage (peritoneal washings). Moreover, treatment with transforming growth factor-β enhanced the anti-cancer effect of docetaxel via induction of cell differentiation/asymmetric cell division of the CXCR4-positive gastric CSCs even in a dormant state. Therefore, differentiation inducers hold promise for obtaining the maximum therapeutic outcome from currently available anti-cancer drugs through re-cycling of CSCs.

Endoscopic Resection is Infeasible for Early Gastric Cancers with Undifferentiated Components

BACKGROUND/AIMS

Aim of this study is to find subgroup of early gastric cancer with lymph node metastasis for which successive further surgical operation is needed after endoscopic resection.

METHODOLOGY

A total of 559 lesions of early gastric cancer, which had undergone curative gastrectomy, were enrolled in this study. We retrospectively investigated 10 clinicopathological factors predictive of lymph node metastasis by univariate and multivariate analysis. We showed the frequency of lymph node metastasis of subgroups in combination of independent factors selected by multivariate analysis.

RESULTS

Lymph node metastases were detected in 57 lesions (10.2%). Univariate analysis revealed that lesion size > 30 mm, undifferentiated components, sm massive invasion, lymphatic invasion and venous invasion were factors significantly correlated with lymph node metastasis. By multivariate analysis, risk factors for lymph node metastasis were lesion size > 30 mm, undifferentiated components, sm massive invasion, and lymphatic invasion, with odds ratios of 2.17, 2.30, 5.88 and 8.24, respectively. In lesions with undifferentiated components, LNM were found in all subgroups.

CONCLUSIONS

When we treat early gastric cancers contained undifferentiated components, even if they are predominantly differentiated-type intramucosal lesions, an additional surgical procedure should be considered or careful follow-up is required.

Palliative benefit of novel cell-free and concentrated ascites reinfusion therapy (CART) for refractory ascites associated with cancerous peritonitis

e20591

Background: Refractory ascites associated with cancerous peritonitis causes severe abdominal distention, dyspnea and appetite loss, resulting in loss of patients’ activities of daily living (ADL) and discontinuation of their treatment for cancer such as chemotherapy. To improve the symptoms, we have developed a novel cell-free and concentrated ascites reinfusion therapy (CART) which is modified from a conventional CART approved by the Ministry of Health, Labor and Welfare in Japan and examined the efficacy in a pilot study. Methods: 87 patients with cancerous ascites were enrolled and subjected to novel CART from April 2012 to November 2012. The response was assessed by improvement of their ADL. Patients were asked in the form of questionnaires about general malaise, abdominal distention, abdominal pain, nausea, dyspnea, sleep disturbance, appetite loss, disturbance in gait, discomfort and frustration before and after treatment and each point was scored on a scale of zero to ten (ten being severe). Abdominal and thigh circumferences were also examined before and after treatment to evaluate efficacy. This study was approved by the ethics review committee of Kaname-cho hospital. Results: On average, 8.3 ± 4.4 L (range 2.3-27.0) of cancerous ascites was filtrated and concentrated to 0.69 ± 0.28 L (range 0.2-1.6) by novel CART. Any severe adverse events except fever were not observed. After treatment, the scores of all points were significantly improved. For example, abdominal distention was improved by 8.1 ± 2.4 vs. 2.0 ± 2.4 (p<0.0001), dyspnea by 3.7 ± 3.3 vs. 1.3 ± 2.1 (p<0.0001), and appetite loss by 5.3 ± 4.3 vs. 3.1 ± 3.4 (p<0.0001). Abdominal and thigh circumferences were also decreased by -13.3 ± 7.5 cm (p<0.0001) and -2.7 ± 2.6 cm (p<0.0001), respectively. Conclusions: This novel CART system is capable to process over 20 L of cancerous ascites and immediately improve their ADL and edematous lesions. Some patients also restarted anticancer treatment such as chemotherapy. Taken together, this CART is safe and effective for palliative care of patients with cancerous ascites.

Novel cell-free and concentrated ascites reinfusion therapy (KM-CART) for refractory ascites associated with cancerous peritonitis: its effect and future perspectives

BACKGROUND

We have actively carried out cell-free and concentrated ascites reinfusion therapy (CART) for refractory ascites. However, with conventional CART, the membrane becomes clogged after processing about 2 L of cancerous ascites fluid due to the fact that it is rich in cellular and mucous components; it is therefore difficult to process the entire volume of collected ascites.

METHODS

We developed KM-CART which includes a membrane cleaning function, and applied it in 73 cases of cancerous ascites, after its basic functions had been evaluated in 11 cases of refractory cancerous ascites.

RESULTS

On average, using KM-CART, 6.4 L (range 1.7-14.9 L) of ascites were filtrated and concentrated to 0.8 L (0.2-2.0 L) in 57 min (5-129 min); the membrane was cleaned an average of three times (range 0-10 times) and this enabled the processing of more ascites in a shorter period. In addition, the circuit and the handling were both markedly simple, and fever, which has been the most notable adverse effect with the conventional system, was not an issue.

CONCLUSION

Since KM-CART was safe and is expected to improve the subjective symptoms and general condition of the patient, it is proposed that this novel system should actively be used not only for palliation but also as supplementary treatment for cancerous peritonitis.

Immunohistochemical analysis of colorectal cancer with gastric phenotype: claudin-18 is associated with poor prognosis

Claudin-18 plays a key role in constructing tight junctions, and altered claudin-18 expression has been documented in various human malignancies; however, little is known about the biological significance of claudin-18 in colorectal cancer (CRC). The aim of this study is to investigate the significance of claudin-18 expression in CRC and its association with clinicopathological factors. We performed clinicopathological analysis of claudin-18 expression in a total of 569 CRCs by immunohistochemistry. Moreover, we investigated the association between claudin-18 and various markers including gastric/intestinal phenotype (MUC5AC, MUC6, MUC2 and CD10), CDX2, claudin-3, claudin-4, p53 and Ki-67. Claudin-18 expression was detected in 21 of the 569 CRCs (4%) and was seen exclusively on the cell membrane. Positive expression of claudin-18 showed a significant correlation with positive expression of MUC5AC (P < 0.0001) and negative expression of CDX2 (P= 0.0013). The prognosis of patients with positive claudin-18 expression was significantly poorer than in negative cases (P= 0.0106). Multivariate analysis revealed that T grade, M grade and claudin-18 expression were independent predictors of survival in patients with CRC. We revealed that claudin-18 expression correlates with poor survival in patients with CRC and is associated with the gastric phenotype.

Immunostaining of gastric cancer with neuroendocrine differentiation: Reg IV-positive neuroendocrine cells are associated with gastrin, serotonin, pancreatic polypeptide and somatostatin

We previously reported that Reg IV is associated with neuroendocrine (NE) differentiation in gastric cancers. The aim was to examine which NE hormone products are related to Reg IV-positive NE cells and their roles in gastric cancers. In the present study, we performed immunohistochemical analysis in a tissue microarray (TMA) of a consecutive series of 630 cases with ten different antibodies, including chromogranin A, synaptophysin and neural cell adhesion molecule (NCAM) as NE differentiation markers, and gastrin, serotonin, calcitonin, gastrin-releasing peptide (GRP), pancreatic polypeptide (PP), somatostatin and glucagon as NE hormones. In 630 cases, we identified 205 (33%) with NE differentiation and 147 (23%) positive for Reg IV. Reg IV-positive cases showed NE differentiation more frequently than Reg IV-negative cases (P < 0.0001). In 205 cases with NE differentiation, Reg IV-positive cases expressed serotonin (P= 0.0032) and somatostatin (P= 0.036) more frequently than Reg IV-negative cases. Double immunofluorescence staining revealed co-expression of Reg IV with gastrin, serotonin and PP. These results indicate that Reg IV might be a mediating factor of several NE hormones.

[Case of gastric cancer with recurrence of carcinomatous lymphangiosis of the lung 7.6 years after surgery and successfully treated with S-1/low-dose CDDP/Lentinan combination therapy]

A 78-year-old woman underwent gastrectomy for type 3 gastric cancer with pyloric stenosis, which was detected in November 1997. Thoracic and abdominal CT and other diagnostic procedures were conducted regularly for 5 years after surgery. The patient was recurrence-free and her clinical course was satisfactory. Starting in early May 2005, however, she began to experience respiratory difficulty at exertion, which exacerbated rapidly thereafter. Examination at a department of respiratory physiology led to a diagnosis of a recurrence of stomach cancer and carcinomatous lymphangiosis+lymphatic metastasis to the peritoneal cavity. She was referred to us for palliative care. The accentuated respiratory difficulty was eased with oxygen inhalation and opioid administration. With improvement in her respiratory condition, a combination of S-1 80 mg/day, CDDP 10 mg x once/week and Lentinan 1 mg x twice/week, was initiated. Within about 2 weeks, her respiratory difficulty was eliminated and after 4 weeks x 2 courses, the tumor images were no longer recognized in the thoracic and abdominal CTs. The combination therapy of S-1/low-dose CDDP/Lentinan is free of evident adverse effects and may be a potent therapeutic alternative as a palliative therapy for malignant stomach cancers in elderly patients or those in a poor systemic condition.

En bloc resection for primary non-Hodgkin's lymphoma of the descending colon with massive extension into the neighboring organs

A 79-year-old female who was surgically treated and received adjuvant chemotherapy for primary non-Hodgkin's lymphoma of the descending colon with massive extension into the pancreatic tail, spleen, and left kidney is herein reported. The patient had acute colonic obstruction and an urgent laparotomy was performed because endoscopic decompression using a transnasal ileus tube could not be done. We performed a left colectomy with an en bloc resection of the neighboring organs, followed by the creation of an end colostomy. The patient had no major postoperative complications and is well without any recurrence of lymphomas 6 months after surgery.

Molecular characteristics of differentiated-type gastric carcinoma with distinct mucin phenotype: LI-cadherin is associated with intestinal phenotype

Gastric carcinomas (GC) are classified into four phenotypes on the basis of the mucin expression profile: G type (gastric or foveolar phenotype), I type (intestinal phenotype), GI type (intestinal and gastric mixed phenotype) and N type (neither gastric nor intestinal phenotype). Immunohistochemistry was used to examine the expression of epidermal growth factor receptor (EGFR), E-cadherin, liver-intestine (LI)-cadherin, CD44v9 and p53 and correlation of these molecules with mucin phenotype and tumor stage was evaluated. Overexpression of EGFR and LI-cadherin, reduced expression of E-cadherin and abnormal expression of p53 were observed more frequently in advanced GC than in early GC. Among I-type GC, overexpression of EGFR and reduced expression of E-cadherin were observed more frequently in advanced tumors than in early tumors. Among G-type GC, reduced expression of E-cadherin was significantly associated with advanced tumors. With respect to the relationship between mucin phenotype and expression of cancer-related molecules, overexpression of LI-cadherin was observed more frequently in I-type (12/25, 48.0%) than in G-type (1/14, 7.1%) GC. I-type GC tended to express LI-cadherin more frequently than GI-type GC. These results provide insights into the molecular characteristics of the distinct mucin phenotype of differentiated-type GC and suggest that LI-cadherin may contribute to the biological behavior of I-type GC.

Differential expression of claudin-2 in normal human tissues and gastrointestinal carcinomas

Claudins are involved in the formation of tight junctions in epithelial and endothelial cells. Claudins form a family of 24 members displaying organ- and tissue-specific patterns of expression. In the present study, we evaluated the specificity of the claudin-2 expression in various normal human tissues and gastrointestinal cancers by quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry. In 14 various normal tissues, claudin-2 mRNA was expressed in the kidney, liver, pancreas, stomach, and small intestine; the highest level of which was detected in the kidney. Colorectal cancers (CRCs) expressed claudin-2 mRNA at high levels. Immunohistochemical analysis of claudin-2 in 146 gastric cancers (GCs) and 99 CRCs demonstrated claudin-2 expression in 2.1% of GCs and 25.3% of CRCs, respectively. There was no obvious correlation between claudin-2 expression and clinicopathological parameters of CRCs. These results suggest that the expression of claudin-2 may involve organ specificity, and increased expression of claudin-2 may participate in colorectal carcinogenesis.

No evidence of correlation between the single nucleotide polymorphism of DNMT3B promoter and gastric cancer risk in a Japanese population

DNA methylation is a major epigenetic modification in humans, and aberrant DNA methylation may play an important role in the development of various cancers through the silencing of some tumor suppressor genes. DNMT3B is required for the establishment and maintenance of genomic methylation patterns. The -149 C/T single nucleotide polymorphism (SNP) in the promoter of DNMT3B has been identified. This SNP influences DNMT3B promoter function, with the T allele having greater activity than the C allele, and is associated with an increased risk of lung cancer. The purpose of our study was to investigate the correlation between the DNMT3B promoter polymorphism and the development and progression of gastric cancer. We analyzed the SNP of the DNMT3B promoter in 152 gastric cancer patients and 247 controls from a Japanese population using PCR-RFLP and sequencing analysis, and also studied the association between the genotypes of DNMT3B and clinicopathological parameters among cases. Allelic difference was not found between gastric cancer patients and control subjects at the target site, -149 bp from the transcriptional start site in the DNMT3B gene promoter. Only the T/T genotype was detected in all gastric cancer patients and control subjects. We concluded that there was no association between SNP of the DNMT3B promoter and gastric cancer risk in a Japanese population.

DNA methylation profiles of differentiated-type gastric carcinomas with distinct mucin phenotypes

Gastric carcinomas (GC) are classified into four phenotypes according to mucin expression. Previous studies revealed the association of distinct genetic profiles in GC with mucin phenotypic expression; however, the roles of epigenetic changes, such as DNA methylation, are poorly understood. We examined whether the phenotypic expression of GC was associated with DNA methylation of hMLH1, MGMT, p16(INK4a), RAR-beta or CDH1. Expression of HGM, M-GGMC-1, MUC2, and CD10 was analyzed immunohistochemically in 33 advanced GC with differentiated histology. HGM was expressed in 14 (42.4%) cases, M-GGMC-1 in five (15.2%) cases, MUC2 in 15 (45.5%) cases and CD10 in 18 (54.5%) cases. DNA methylation was detected in five (15.2%) cases for hMLH1, 11 (33.3%) cases for MGMT, 13 (39.4%) cases for p16(INK4a), 17 (51.5%) cases for RAR-beta and 14 (42.4%) cases for CDH1 by bisulfite-polymerase chain reaction and methylation-specific polymerase chain reaction. DNA methylation of hMLH1 occurred more frequently in MUC2-negative GC than in MUC2-positive GC (P = 0.0488, Fisher's exact test). In contrast, MGMT was more frequently methylated in MUC2-positive GC than in MUC2-negative GC (P = 0.0078, Fisher's exact test). There was no correlation between gastric or intestinal-markers and methylation of the p16(INK4a), RAR-beta and CDH1 genes. These results indicate that DNA methylation of specific genes, such as hMLH1 and MGMT, may be involved partly in the distinct phenotypic expression of GC.

A single nucleotide polymorphism in the extracellular domain of TRAIL receptor DR4 at nucleotide 626 in gastric cancer patients in Japan

Death receptor 4 (DR4) is a member of the tumor necrosis factor-related apoptosis-inducing ligand receptor genes. A single nucleotide polymorphism (Thr or Arg, C or G) in the extracellular domain was reported to be associated with a risk of lung cancer, head and neck cancer, and bladder cancer. In this study, we examined the association between the DR4 polymorphism and gastric cancer. The Thr/Thr, Thr/Arg and Arg/Arg genotypes were found in 250 (91.2%), 23 (8.4%) and 1 (0.4%) of 274 gastric cancer patients and in 317 (92.2%), 21 (6.1%) and 6 (1.7%) of 344 control subjects, respectively. The OR of Thr/Arg or Arg/Arg genotype did not reveal a significantly enhanced risk of 1.13 (95% CI, 0.63-2.00) compared to Thr/Thr genotype, suggesting that the DR4 polymorphism did not modify the risk of gastric cancer. In patients, no association between the genotype and clinicopathological characteristics (depth of invasion, lymph node metastasis, distant metastasis, stage and grade of differentiation) of gastric carcinoma was found. DR4 was constantly expressed in gastric carcinoma, but not in non-neoplastic gastric epithelium in immunohistochemistry. In conclusion, a Thr to Arg single nucleotide polymorphism in the extracellular domain of DR4 could not be associated with the development and progression of gastric cancer.

Mucin and differentiation in Epstein-Barr virus-associated gastric carcinoma

BACKGROUND/AIMS

Epstein-Barr virus (EBV) is present in roughly 1 in 10 cases of gastric carcinoma, particularly in undifferentiated adenocarcinomas. To clarify the histological developmental processes in EBV-associated gastric carcinoma, we investigated the presence of EBV infection, changes in the degree of differentiation within lesions, and mucin phenotypes of gastric carcinomas.

METHODOLOGY

We had already examined 124 gastric carcinomas using in situ hybridization for EBV-encoded small RNA1 (EBER-1) and 12 lesions were EBER-1-positive. From these lesions we selected 8 carcinomas positive for EBER-1, and then chose 16 EBER-1-negative carcinomas as controls. Hematoxylin and eosin (H&E) stained specimens were examined for changes in histological type within each lesion. Mucin phenotypes of the specimens were determined using human gastric mucin (HGM), MUC2 and CD10 immunostaining.

RESULTS

Of the EBER-1-positive lesions, 50% exhibited the gastric type mucin phenotype, whereas only 19% of the EBER-1-negative lesions were of the gastric phenotype. Changes in the histological type were seen within 75% of the EBER-1-positive lesions and within 62.5% of the EBER-1-negative lesions.

CONCLUSIONS

The gastric mucin phenotype tended to be more common in the EBV-associated gastric carcinomas. The influence of EBV infection on the change in the histological type within the lesion was considered to be slight.

A single nucleotide polymorphism in the 5' untranslated region of the EGF gene is associated with occurrence and malignant progression of gastric cancer

OBJECTIVE

Epidermal growth factor (EGF) has many biological functions and plays an important role in the progression of various tumors including gastric cancer. An A-G single nucleotide polymorphism (SNP) at position 61 in the 5'-untranslated region (UTR) of the EGF gene has recently been reported to be associated with different levels of EGF production. We examined whether this polymorphism is correlated with the development and malignant phenotypes of gastric cancer.

METHODS

The study population included 200 gastric cancer patients and 230 healthy control subjects. The SNP in the 5'-UTR of the EGF gene was analyzed by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

The A allele was significantly less frequent in patients than in controls (p = 0.01). Individuals with the A/A or A/G genotype showed a significantly lower risk of gastric cancer than those with the G/G genotype [adjusted odds ratio (OR) = 0.56], whereas the same genotypes were associated with malignant progression of this cancer, e.g. deeper tumor invasion, increased lymph node metastasis and advanced clinical stage, and histological classification in gastric cancer patients (adjusted OR = 1.80, 1.98, 2.26 and 1.89, respectively).

CONCLUSIONS

Our findings suggest that the A-G polymorphism of EGF is involved not only in the occurrence but also in the malignant progression of gastric cancer.

A single nucleotide polymorphism in the MMP-9 promoter affects tumor progression and invasive phenotype of gastric cancer

PURPOSE

Matrix metalloproteinase-9 (MMP-9, gelatinase B) plays a key role in cancer invasion and metastasis by degradating the extracellular matrix (ECM) and basement membrane barriers. A cytosine (C)-thymidine (T) single nucleotide polymorphism (SNP) at position -1562 in the MMP-9 promoter is reported to affect expression of this gene. The purpose of this study was to investigate the relation between the -1562 C/T polymorphism and the development and progression of gastric cancer.

METHODS

The study population included 177 gastric cancer patients and 224 healthy control subjects. The SNP in the MMP-9 promoter was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing. Genotype frequencies were compared between patients and controls, and the association of genotypes with clinicopathological features was studied.

RESULTS

Genotype frequencies in gastric cancer patients were similar to those in control subjects (P = 0.223). However, significant association was found between degree of tumor invasion, clinical stage, and lymphatic invasion and the MMP-9 polymorphism in gastric cancer patients (P<0.05, for each).

CONCLUSIONS

Our results indicate that the T allele in the MMP-9 promoter is associated with the invasive phenotype of gastric cancer.

DNA methylation of multiple genes in gastric carcinoma: association with histological type and CpG island methylator phenotype

Hypermethylation of CpG islands is associated with silencing of various tumor suppressor genes. Recent studies on colorectal and gastric cancer have identified a CpG island methylator phenotype (CIMP), which involves the targeting of multiple genes by promoter hypermethylation. For determination of association between DNA methylation pattern or histological type and CIMP status in gastric carcinoma, CpG islands in the promoters of hMLH1 and CDH1 genes, CpG islands overlapping exon 1 of MGMT and p16(INK4a) genes, and a non-CpG island in exon 1 of the RAR-beta gene were studied. The presence of the CIMP was determined by monitoring five methylated in tumor (MINT ) loci in 103 gastric carcinomas. Among the 103 gastric carcinomas, DNA hypermethylation was detected in the following frequencies: 14 (14%) for hMLH1, 26 (25%) for MGMT, 26 (25%) for p16(INK4a), 54 (52%) for CDH1, and 53 (52%) for RAR-beta. Forty-two (41%) of 103 gastric carcinomas were positive for the CIMP. CIMP and hypermethylation of p16(INK4a) gene were found more frequently in intestinal and diffuse-adherent types than in diffuse-scattered type (P = 0.013 and 0.017, respectively). In contrast, hypermethylation of the CDH1 and RAR-beta genes was more common in the diffuse-scattered type than in the other types (P = 0.008 and 0.007, respectively). In intestinal- and diffuse-adherent-type gastric carcinomas, we found significant associations between the presence of the CIMP and hypermethylation of several genes: hMLH1 (P = 0.006), p16(INK4a) (P = 0.018), CDH1 (P = 0.024), and RAR-beta (P = 0.044). Our overall results suggest that in some intestinal- and diffuse-adherent-type gastric carcinomas, DNA hypermethylation affects non-specific gene promoters concordantly, at least in part, whereas in diffuse-scattered-type gastric carcinoma, DNA hypermethylation affects specific genes such as CDH1 and RAR-beta.

Epstein-Barr virus association is rare in esophageal squamous cell carcinoma

BACKGROUND

A critical role of Epstein-Barr virus (EBV) in carcinogenesis of nasopharyngeal squamous cell carcinoma and gastric adenocarcinoma is strongly suspected. We analyzed the possible EBV association for Japanese squamous cell carcinoma (SCC)-dominant esophageal cancer cases.

METHODS

We retrospectively screened 36 surgically resected esophageal cancer lesions from 36 patients mainly with SCC using in situ hybridization (ISH) for EBV-encoded small RNA1 (EBER-1). EBV DNA analysis using real-time quantitative polymerase chain reaction (Q-PCR) was performed for three recent cases.

RESULTS

We found no EBER-1-positive cancer cell in any tested esophageal cancer lesion. There were many EBER-1-positive tumor-infiltrating lymphocytes in the basaloid SCC lesion and a small number of positive lymphocytes in the other five advanced SCC lesions (14.7% of SCC). One SCC lesion with a highcopy number of EBV DNA had EBER-1-positive lymphocytes.

CONCLUSIONS

EBV is rarely associated with esophageal SCC, and may appear through tumorinfiltrating lymphocytes in some advanced lesions.

A single nucleotide polymorphism in the transmembrane domain coding region of HER-2 is associated with development and malignant phenotype of gastric cancer

Alterations of the HER-2 (erbB-2/neu) proto-oncogene have been associated with carcinogenesis and poor prognosis of certain cancers. A single nucleotide polymorphism (Ile/Val, A/G) in the transmembrane domain was reported to be associated with a risk of breast cancer. In our study, we examined the association between the HER-2 polymorphism and gastric carcinoma. The Ile/Ile, Ile/Val and Val/Val genotypes were found in 146 (68.9%), 56 (26.4%) and 10 (4.7%) of 212 gastric cancer patients and in 234 (81.5%), 48 (16.7%) and 5 (1.8%) of 287 control subjects, respectively. The Ile/Val or Val/Val genotype was significantly more frequent in patients than in controls (p = 0.005 and 0.033, respectively). The OR of Val/Val genotype then revealed a significantly enhanced risk of 3.25 (95% CI 1.09-9.70) compared to Ile/Ile genotype; heterozygous Ile/Val genotype showed an intermediate risk of 1.97 (1.27-3.06). In patients, carcinomas of advanced stage were significantly more frequent in patients with Ile/Val or Val/Val genotype than those with Ile/Ile genotype (p < 0.001). The logistic regression analysis for tumor invasion, lymph node metastasis and distant metastasis revealed that lymph node metastasis was most closely associated with the HER-2 genotype. These results suggest that this nucleotide polymorphism in the transmembrane domain-coding region of HER-2 could be associated with development of gastric carcinoma and may serve as a predictor of risk for a malignant phenotype of gastric cancer. The association of HER-2 genotype with clinicopathologic characteristics of gastric cancer was also suggested, which has to be confirmed with a larger sample size.

DNA hypermethylation and histone hypoacetylation of the HLTF gene are associated with reduced expression in gastric carcinoma

The SWI/SNF proteins are ATP-dependent chromatin remodeling enzymes that have been implicated in the regulation of gene expression. Recent studies have shown that members of the SWI/SNF superfamily can function as tumor suppressor genes. DNA methylation and transcriptional inactivation of the HLTF gene, which is a homologue to the SWI/SNF genes, have been observed in colon cancer. In the present study, we studied the DNA methylation status of the HLTF gene by methylation-specific PCR in 50 gastric carcinoma tissues, and seven gastric carcinoma cell lines and compared the methylation status with the levels of HLTF mRNA expression. DNA methylation of the HLTF gene was found in 25 (50%) of 50 gastric carcinomas, and levels of HLTF mRNA were associated with methylation status of HLTF (P = 0.027; Mann-Whitney U test). No correlations were found between HLTF mRNA levels and DNA methylation and T grade, N grade, tumor stage, or histological type. In corresponding non-neoplastic mucosae, DNA methylation of the HLTF gene was found in 1 (7%) of 15 samples. The methylated allele was not detected in any of 10 normal gastric mucosae from 10 healthy volunteers. Among seven gastric carcinoma cell lines, the KATO-III cell line showed loss of HLTF mRNA expression associated with DNA methylation. This loss was rectified by treatment with both Aza-2'-deoxycytidine, a demethylating agent, and trichostatin A, a histone deacetylase inhibitor. Chromatin immunoprecipitation assay revealed that the acetylation levels of histones H3 and H4 in the 5' CpG island of the HLTF gene were inversely associated with DNA methylation status. These results suggest that transcriptional inactivation of HLTF by aberrant DNA methylation and histone deacetylation may be involved in stomach carcinogenesis through down-regulation of HLTF expression.

Reduced expression of the TSP1 gene and its association with promoter hypermethylation in gastric carcinoma

Thrombospondin-1 (TSP1) is a potent peptide shown in some tumor systems to be linked with angiogenesis. Epigenetic alteration of TSP1 has been reported in various primary tumors. However, the expression pattern of TSP1 has not been characterized in gastric carcinoma. We measured levels of TSP1 mRNA expression using quantitative RT-PCR in 30 gastric carcinomas and 10 non-neoplastic mucosae. In addition, we examined the correlation of the levels of TSP1 mRNA expression levels with promoter methylation status of TSP1 monitored by methylation-specific PCR as well as P53 mutation status detected by PCR-single-strand conformation polymorphism. Promoter hypermethylation of the TSP1 gene was found in 10 (33%) of 30 gastric carcinomas, and TSP1 mRNA expression levels were associated with promoter hypermethylation of TSP1 (p = 0.017; Mann-Whitney U test). P53 mutation was found in 5 (17%) of 30 gastric carcinomas, however, TSP1 mRNA expression was not associated with P53 mutation status (p = 0.858; Mann-Whitney U test). There was no correlation between TSP1 mRNA expression levels and T grade, N grade, tumor stage, or histological type. Our results suggest that transcriptional inactivation of TSP1 by aberrant DNA methylation of the promoter region may participate partly in stomach carcinogenesis through TSP1 down-regulation.

Acetylated histone H4 is reduced in human gastric adenomas and carcinomas

Acetylation of core histones is closely linked to transcriptional activation of various genes. The acetylation levels of nucleosomal histones can be modified through a balance of histone acetyltransferases and deacetylases. To elucidate the role of histone acetylation in human gastric carcinogenesis, we studied the status of histone H4 acetylation in gastric carcinoma tissues and corresponding non-neoplastic mucosa. The status of histone acetylation was assessed by examining the expression of acetylated histone H4 through Western blotting and immunohistochemistry using an anti-acetylated histone H4 antibody. The levels of acetylated histone H4 expression were obviously reduced in 72% (13/18) of gastric carcinomas in comparison with non-neoplastic mucosa by Western blotting. In immunohistochemistry, acetylated histone H4 was clearly detected in the nuclei of both non-neoplastic epithelial and stromal cells, whereas the levels of acetylated histone H4 were heterogeneous or reduced in 66% (38/57) of gastric carcinomas and 46% (6/13) of gastric adenomas. Reduced expression of acetylated histone H4 was also observed in some areas of intestinal metaplasia adjacent to carcinomas. Reduction in the expression of acetylated histone H4 was significantly correlated with advanced stage, depth of tumor invasion and lymph node metastasis. These results suggest that low levels of histone acetylation may be closely associated with the development and progression of gastric carcinomas, possibly through alteration of gene expression.

Distinct promoter hypermethylation of p16INK4a, CDH1, and RAR-beta in intestinal, diffuse-adherent, and diffuse-scattered type gastric carcinomas

Hypermethylation of CpG islands in gene promoters is associated with silencing of various tumour suppressor genes. Recent studies of colorectal and gastric carcinomas have defined a CpG island methylator phenotype (CIMP), which involves the targeting of multiple genes by promoter hypermethylation. In this study, methylation-specific polymerase chain reaction (PCR) was performed to study methylation of CpG islands in the promoters of the p16(INK4a), cadherin 1 (CDH1), and retinoic acid receptor-beta (RAR-beta) genes in 45 gastric carcinomas and to investigate whether CDH1 and RAR-beta promoter hypermethylation is associated with CIMP-positive gastric carcinoma. CpG island hypermethylation of the p16(INK4a), CDH1, and RAR-beta promoters was detected in 12 (27%), 26 (58%), and 24 (53%) of the 45 gastric carcinomas, respectively. Hypermethylation of the p16(INK4a) promoter was more common in intestinal type than in diffuse type gastric carcinomas (p = 0.0023; Fisher's exact test) and was inversely associated with p53 mutations (p = 0.0225; Fisher's exact test). However, CDH1 and RAR-beta promoter hypermethylation was observed more frequently in diffuse-scattered type gastric carcinoma than in other types (intestinal and diffuse-adherent types) (p = 0.0175 and p = 0.0335, respectively; Fisher's exact test) and was not associated with p53 mutation status. Moreover, hypermethylation of the CDH1 and RAR-beta promoters occurred concordantly (p < 0.0001; Fisher's exact test). These results suggest that at least two types of promoter methylation status are involved in the development of the intestinal (p16(INK4a) promoter hypermethylation) and diffuse-scattered types (CDH1 and RAR-beta promoter hypermethylation) of gastric carcinoma.

High prevalence of Epstein-Barr virus in gastric remnant carcinoma after Billroth-II reconstruction

BACKGROUND

Epstein-Barr virus (EBV) has been detected in about 10% of gastric carcinoma cases worldwide, and a high prevalence of EBV involvement in gastric remnant carcinoma has been reported recently. Details of the background remnant stomach of EBV-positive lesions, however, have not been well clarified.

METHODS

We screened 17 consecutive gastric remnant carcinoma lesions resected surgically. To detect EBV, we used in situ hybridization (ISH) for EBV-encoded small RNA1 (EBER-1) and we compared the clinicopathologic feature between EBV-positive and -negative gastric remnant carcinoma cases.

RESULTS

EBV was detected in 41.8% (7 of 17) of the lesions by EBER-1 ISH. All 7 EBV-positive lesions developed in the anastomotic site had undergone Billroth-II reconstruction excess 20 years previously (mean 26.4 years). Histologically, all EBV-positive lesions were poorly differentiated adenocarcinomas with intense lymphocyte infiltration. In the adjacent mucosa of carcinomas, moderate or marked intestinal metaplasia was found in 85.7% (6 of 7) of EBV-positive lesions and in 40% (4 of 10) of EBV-negative lesions.

CONCLUSIONS

EBV infection is strongly associated with gastric remnant carcinoma. Atrophic change of remnant gastritis in Billroth-II anastomoses is considered to be the carcinogenic background for EBV-positive gastric remnant carcinoma.

High prevalence of Epstein-Barr virus in gastric remnant carcinoma after Billroth-II reconstruction

BACKGROUND

Epstein-Barr virus (EBV) has been detected in about 10% of gastric carcinoma cases worldwide, and a high prevalence of EBV involvement in gastric remnant carcinoma has been reported recently. Details of the background remnant stomach of EBV-positive lesions, however, have not been well clarified.

METHODS

We screened 17 consecutive gastric remnant carcinoma lesions resected surgically. To detect EBV, we used in situ hybridization (ISH) for EBV-encoded small RNA1 (EBER-1) and we compared the clinicopathologic feature between EBV-positive and -negative gastric remnant carcinoma cases.

RESULTS

EBV was detected in 41.8% (7 of 17) of the lesions by EBER-1 ISH. All 7 EBV-positive lesions developed in the anastomotic site had undergone Billroth-II reconstruction excess 20 years previously (mean 26.4 years). Histologically, all EBV-positive lesions were poorly differentiated adenocarcinomas with intense lymphocyte infiltration. In the adjacent mucosa of carcinomas, moderate or marked intestinal metaplasia was found in 85.7% (6 of 7) of EBV-positive lesions and in 40% (4 of 10) of EBV-negative lesions.

CONCLUSIONS

EBV infection is strongly associated with gastric remnant carcinoma. Atrophic change of remnant gastritis in Billroth-II anastomoses is considered to be the carcinogenic background for EBV-positive gastric remnant carcinoma.

DNA methylation status of hMLH1, p16(INK4a), and CDH1 is not associated with mRNA expression levels of DNA methyltransferase and DNA demethylase in gastric carcinomas

DNA methyltransferase and DNA demethylase are enzymes potentially affecting promoter methylation status. We examined levels of DNA methyltransferase (DNMT1, DNMT3a, DNMT3b) and DNA demethylase (MBD2) mRNA expression by semi-quantitative RT-PCR. In addition, we examined promoter methylation status of hMLH1, p16(INK4a), and CDH1 by methylation-specific PCR since all three of these genes are reported to be hypermethylated in gastric carcinoma. MBD2 appeared to be down-regulated in neoplasms. The levels of DNMT1, DNMT3a, DNMT3b, and MBD2 mRNA expression were not associated with either tumor stage or histologic type. Promoter hypermethylation of hMLH1, p16(INK4a), and CDH1 was detected in 5/20 (25%), 8/20 (40%) and 8/20 (40%) of gastric carcinomas, respectively. There was no clear relation between DNA methylation status of hMLH1, p16(INK4a), and CDH1 and the mRNA expression levels of DNMT1, DNMT3a, DNMT3b or MBD2. We divided the examined cases into two groups according to the number of hypermethylated genes. Cases with more than two hypermethylated genes comprised a hypermethylation group, and cases with no hypermethylation comprised a non-hypermethylation group. We found no group association for levels of DNMT1, DNMT3a, DNMT3b, and MBD2 mRNA expression. Our results suggest that the mRNA expression levels for pro-methylating (DNMT1, DNMT3a, DNMT3b) and anti-methylating (MBD2) enzymes is not a critical determinate of tumor-specific promoter hypermethylation of hMLH1, p(16INK4a), or CDH1 in gastric carcinoma.

Transport Properties of Cation Exchange Membranes in the Presence of Ether Compounds in Electrodialysis

Ether compounds such as ethylene glycols with different molecular weights and crown ethers have good affinity to the cation exchange membranes, sulfonated styrene-divinylbenzene membrane (sodium ion form) and perfluorocarbon sodium sulfonate membrane. The impregnated amount of ethylene glycols in the membranes was higher than the water content of the membranes. After the ether compounds had been impregnated in the cation exchange membranes, electrodialysis of mixed salt solutions (1:1 mixture of alkaline earth metal ions or potassium ions and sodium ions) was carried out in the presence of the compounds to observe the change in permselectivity between two cations. Though current efficiency did not change in the presence of the compounds, transport numbers of alkaline earth metal ions relative to sodium ions decreased. Namely, sodium ions permeated through the membrane more selectively than alkaline earth metal ions. This is due mainly to a decrease in the mobility of alkaline earth metal ions in the membrane phase and partially to a decrease in the ion exchange equilibrium constant of alkaline earth metal ions to sodium ions with the membrane. This originates from the difference in ion-dipole interaction between cations and ether groups. The transport number of potassium ions relative to sodium ions also decreased in the presence of the compounds. In particular, the permeation of potassium ions relative to sodium ions remarkably decreased in the presence of 18-crown-6 in the membrane and in the solution due to the formation of a strong complex between potassium ions and 18-crown-6. Copyright 1999 Academic Press.

Endoscopic and pathologic features of Epstein-Barr virus-associated gastric carcinoma

BACKGROUND

Although the presence of Epstein-Barr virus has been documented in approximately 7% of patients with gastric carcinoma, the clinical features of Epstein-Barr virus-associated carcinoma have not been well documented. We studied the histologic and endoscopic characteristics of Epstein-Barr virus-associated gastric carcinoma.

METHODS

We tested 124 gastric carcinomas from 117 patients using in situ hybridization for Epstein-Barr virus encoded small RNA1. The histologic and endoscopic findings in the Epstein-Barr virus-associated groups and the negative control groups were analyzed and compared.

RESULTS

Twelve tumors (9.7%) were identified as Epstein-Barr virus associated. These lesions were located mainly in the upper part of the stomach (p < .05) and had a diffuse-type histology (p < .05) compared with those in the control group. Six of seven (85.7%) early Epstein-Barr virus-associated lesions were type 0 IIc (superficial depressed) or a combined type, and 42.9% were accompanied by submucosal nodules of carcinoma with lymphoid stroma. Four of five (80%) advanced Epstein-Barr virus-associated tumors were type 3 (ulcerated without definite limits), thought to be the advanced shape of superficial depressed lesions.

CONCLUSIONS

Epstein-Barr virus-associated gastric carcinomas often appear as superficial depressed or ulcerated lesions in the upper part of the stomach and have a diffuse-type histology with lymphoid infiltration.

Heat stable protein with anticoagulant and smooth muscle contractile actions isolated from Habu (Trimeresurus flavoviridis) venom

The biological activity of a Habu (Trimeresurus flavoiridis) venom fraction with drug-metabolizing enzyme inhibitory action was studied. The venom fraction, which was isolated through Sephadex G-100 gel filtration and cation exchange chromatography on Amberlite CG50, caused an increase of vascular permeability and hemorrhage, but these actions were lost after heating at 70 degrees C for 5 min. The fraction showed anticoagulant activity on citrated blood, and this activity remained after heating of the venom. Guinea pig ileum was contracted by treatment with nonheated or heated venom fraction, and these contractions were inhibited with atropine and potentiated with physostigmine. These results suggest that the drug-metabolizing enzyme inhibitor isolated from Habu venom involves the heat stable component with anticoagulant activity and smooth muscle contractile action.

Electron microscopic localization of acridine orange binding to DNA within various human brain tumor cells

The ultracytochemical acridine orange (AO) method has been employed to demonstrate DNA template activity within untreated human brain tumors. A total of 16 biopsies from brain tumors removed for frozen section examination were investigated. Ultrastructural examination revealed that AO binds to DNA exclusively within the extended euchromatin portion of the cell nucleus of brain tumors. The percentage of AO positive cells varied from 6.0 to 48.6% in various types of brain tumors. A few AO reaction products were visible in the nuclei of the endothelial cells and in the pericytes of the capillaries within neoplastic tissue. The present results suggested that untreated human brain tumors exhibit de-repression of DNA template normally repressed in the adult state. This altered DNA templates may be related to abnormal cell proliferation and differentiation diverted from the normal state.