北山 丈二

Background. Zoledronic acid (ZOL) is clinically available for the treatment of skeletal complications. In preclinical studies, strong anti-cancer activities against breast cancer, prostate cancer, and leukemia were reported. It also inhibited the proliferation of cultured human endothelial cells, suggestive of an anti-angiogenic activity. Since ZOL has the tendency to accumulate in bone, we investigated the effect of ZOL on endothelial progenitor cells (EPCs), which originate from the bone marrow, and play important roles in angiogenesis. Materials and methods. Human peripheral blood mononuclear cells were cultured for 7 d to differentiate into EPCs. Cells were treated without/with ZOL or with geranylgeraniol (GGOH). Their endothelial phenotype was confirmed by the expression of CD144 and vascular endothelial growth factor receptor 2 and the tube-like formation ability on Matrigel (Becton Dickinson, Bedford, MA). Annexin V/propidium iodide staining was used to analyze apoptosis. Results. ZOL treatment, even at low doses, from d 2 to 7 of culture resulted in impaired EPC differentiation and could be restored by co-treatment with GGOH. On the other hand, treatment of putative EPCs with ZOL at concentrations higher than 10 gm resulted in induction of apoptosis. Conclusion. ZOL dose-dependently inhibited the differentiation of EPCs, the effect being observed even at low drug levels. At high concentrations, ZOL also induced the apoptotic death of putative EPCs. Since GGOH restored the inhibitory effect of ZOL on EPCs differentiation, the effect of ZOL appears to be dependent on the inhibition of prenylation of small-G-proteins. From these findings, we conclude that ZOL could be a potential anticancer agent by inhibiting angiogenesis. (C) 2009 Elsevier Inc. All rights reserved.

Recent epidemiologic studies have shown a positive association between obesity and certain cancers. Our retrospective studies show that hypertriglyceridemia is an independent risk factor for the development of colonic adenoma and nodal metastasis in early gastric and esophageal cancer in men. High-fat condition may be favorable for the growth of malignant cells. Serum level of adiponectin is reduced in patients with advanced gastric cancer, which may be associated with the positive link between adiposity and cancer. In early gastric cancer, patients with undifferentiated type have lower fat volume than those with differentiated type. Adiposity appears to be closely related with various aspects in pathophysiology of gastrointestinal malignancy. Copyright (c) 2009 S. Karger AG, Basel

Objectives: A dose-escalation study of weekly intraperitoneal paclitaxel (PTX) combined with S-1 and intravenous PTX was performed to determine the maximum-tolerated dose (MTD) and recommended dose (RD) in gastric cancer patients. Patients and Methods: Nine gastric cancer patients with peritoneal dissemination and/or cancer cells on peritoneal cytology were enrolled. PTX was administered intravenously on days 1 and 8 at a fixed dose of 50 mg/m(2), and intraperitoneally with an initial dose of 20 mg/m(2), stepped up to 30 or 40 mg/m(2). S-1 was administered at a fixed dose of 80 mg/m(2)/day for 14 consecutive days, followed by 7 days of rest. A pharmacokinetic study of PTX was also performed. Results: The MTD was determined to be 30 mg/m(2), as 2 of 3 patients developed dose-limiting toxicities, grade 3 febrile neutropenia and diarrhea. Therefore, the RD was determined to be 20 mg/m(2). The intraperitoneal and serum PTX concentration remained effective for over 72 and 48 h, respectively. Conclusions: Combined chemotherapy of S-1 plus weekly intravenous and intraperitoneal PTX was shown to be a safe regimen that should be further explored in clinical trials. Copyright (C) 2009 S. Karger AG, Basel

Background and aim: Intra-peritoneal administration (i.p.) of Taxanes has recently been reported to be effective for the treatment of peritoneal dissemination, presumably because extremely high concentration of the drug is achievable onto the disseminated nodules as compared to intra-venous administration. Here, we aimed to investigate the ability of non-animal stabilized hyaluronic acid (NASHA) to retain the anti-cancer drugs in the peritoneal cavity, and, consequently, improve the efficacy of i.p. administration of paclitaxel. Methods: Mice were inoculated i.p. with MKN45P gastric cancer cells. The mice received i.p. administrations of paclitaxel, without or with NASHA, once a week for 3 consecutive weeks, and the intra-peritoneal nodules were counted after 4 weeks. The ability of NASHA to retain the i.p. administered liquid and paclitaxel in abdominal cavity was also investigated. Finally, the concentration of paclitaxel in metastatic nodule was measured with HPLC. Results: In the group receiving paclitaxel with NASHA, the number of disseminated nodules were significantly smaller than in those receiving paclitaxel without NASHA. The fluid volumes and concentration of paclitaxel recovered from the abdominal cavity as well as the concentrations of paclitaxel in metastatic nodule were significantly increased by the addition of NASHA. Conclusion: Our results indicate that NASHA improves the exposure time of i.p. administrated paclitaxel to disseminated nodules by retaining the drug in the abdominal cavity. Since the material is used in cosmetic surgery with few adverse effects, NASHA can be clinically used as the vehicle for the i.p. administration of anti-cancer agents for advanced gastric cancer with peritoneal dissemination. (c) 2008 Elsevier Ireland Ltd. All rights reserved.

Excessive fat mass is a risk factor for postmenopausal breast cancer. Leptin, a fat cell-derived peptide hormone, elicits a growth-stimulating effect in breast cancer cells with leptin receptor expression, although the leptin-induced signal in malignant cells is not fully understood. Here, we found that exogenous leptin induced tyrosine phosphorylation of HER2 in SKBR3 cells, which showed marked overexpression of HER2. Phosphorylation of HER2 was detected at 2 min and continued up to 120 min after the start of stimulation. Leptin-induced HER2 phosphorylation was partially reduced by an epidermal growth factor receptor inhibitor, AG1478, or a Janus-activated kinase inhibitor, AG490. Leptin also induced phosphorylation of extracellular signal-regulated kinase 1/2, which was mostly abrogated by a HER2 tyrosine kinase inhibitor, AG825. In a proliferation assay, addition of 500 ng/mL leptin increased the proliferation of SKBR3, which was totally inhibited by AG825. Collectively, our data suggest that leptin can transactivate HER2 through both epidermal growth factor receptor and Janus-activated kinase 2 activation, which can cause the growth of breast cancer cells with HER2 overexpression. (c) 2008 Elsevier Inc. All rights reserved.

Background/Aims: Recurrence, which Occurs in about 20-30% of colorectal cancer patients after curative surgical treatment, is an important factor in determining prognosis. Therefore, early detection and prediction of recurrence is an Important issue in the treatment of the disease. Telomerase is a reverse transcriptase that synthesizes telomere DNA, thereby compensating for telomere loss that occurs with each replication cycle, and limits proliferation cells. Telomerase is expressed in the majority of primary human tumors and hTERT is considered one of the most important proteins affecting telomerase activity. We evaluated telomerase activity in mesenteric and peripheral blood samples in addition to hTERT expression in cancerous tissues by means of immunohistochemistry in 120 patients who underwent curative surgical treatment at our department. Methodology: We investigated the factors correlated with recurrence. Results: In univariate analysis, we found recurrence was significantly correlated with positive telomerase activity In the mesenteric vein (p=0.0021), positive telomerase activity in the peripheral vein (p=0.0032), histological type except well differentiated adenocarcinoma (p=0.0013), lymphatic infiltration (p=0.044), lymph node metastasis at surgery (p<0.0001), positive CEA (p=0.0004) and negative TERT immunoreactivity (p=0.012). In multivariate analysis, we found lymph node involvement at surgery (p=0.0045, hazard ratio: 6.21) and positive telomerase activity in peripheral vein (p=0.037, hazard ratio: 3.13) were significantly associated with the existence of recurrence. Conclusions: Our results show that measuring telomerase activity in peripheral blood samples is effective in predicting future recurrence to a degree greater than macroscopically examined tumor depth or other clinicopathological parameters.

Background and Aim: Epidemiological studies have suggested the positive correlation between hyperlipidemia and/or hyperglycemia and colorectal cancer risk. Methods: We retrospectively examined the association between fasting blood sugar (BS) or triglycerides (TG) and the presence of colorectal adenoma, carcinoma in situ and invasive cancer in 867 patients who received total colonoscopy by medical health check. Results: An increased TG level, but not a BS level, was significantly associated with the increased risk of adenoma, although with non-independent multivariate analysis. In contrast, an elevated BS level was identified as an independent risk factor for invasive cancer in 93 patients with carcinoma lesions with an odds ratio of 1.74 (P < 0.05). Conclusion: Our data suggest that hypertriglyceridemia and hyperglycemia may correlate with the development of adenoma and invasive cancer, respectively. The effectiveness of strict BS control in patients with hypertriglyceridemia for the prevention of the invasive colorectal carcinoma deserves further studies.

Background. Visceral obesity is known to be a risk factor for diabetes and cardiovascular disease. Cancer of the gastric cardia has been shown to have a close association with obesity in Western countries. In order to examine the possible relationship between fat volume and the development of gastric cancer (GC), we quantified visceral and subcutaneous fat areas of computed tomography (CT) images of patients with early GC. Methods. A total of 210 patients who underwent endoscopic resection or surgical gastrectomy and whose disease was pathologically diagnosed as early GC were investigated for total fat area (TFA), visceral fat area (VFA), and subcutaneous fat area (SFA) with Fat Scan software, using a CT slice at the umbilical level, and the relationships of these findings with clinical and pathological data were analyzed. The same analysis was performed in 147 patients with early colorectal cancer (CRC). Results. TFA, VFA, and SFA values in GC patients were not significantly different from the values in CRC patients. These values did not differ with the location of the GC. However, patients with undifferentiated-type GC had significantly smaller VFAs and SFAs than those with differentiated-type GC. Among the patients with undifferentiated GC, TFA and SFA values in the patients with submucosal cancer were significantly smaller than those in the patients with mucosal cancer. Conclusion. GC has different associations with adipose tissue volume according to its histological type. As compared with differentiated GC, lower adipose tissue volume may be a preferential environment for the development and progression of undifferentiated GC.

Background/Aims: The p38 mitogen-activated protein kinases. (p38 MAPKs) function in a wide variety,of signaling pathways. However, the role of p38s is cell type- and stimulus-dependent. The present study aimed to evaluate the effects of p38 MAPK inhibitor on human colon cancer cells. Methodology: The effect of p38 MAPK inhibitor, FR167653, on DLD-1 and SW480 was investigated related to cell proliferation, apoptosis induction and caspase activity. Additionally, the effect of FR167653 on colon cancer cell migration, MMPs production and ability to adhere to extracellular matrix was investigated. Results: Inhibitor of p38 MAPK dose-dependently suppressed the proliferative activity of both cell lines, and increased the induction of cell apoptosis. The caspase-3, 8, and 9 activities were accompanied in the pathway. Neither cell migration, MMPs production, nor the ability to adhere extracellular matrix were affected by FR167653. Conclusions: Inhibitor of p38 MAPK suppressed the proliferation of colon cancer cells by induction of cell apoptosis through the caspase activation. The present results suggest the pro-oncogenic role of p38 in colon cancer, and its inhibition would be a novel strategy for the prevention and treatment of colon cancer.

Vaccines targeting tumour angiogenesis were recently shown to inhibit tumour growth in animal models. However, there is still a lack of information about the clinical utility of anti-angiogenic vaccination. Therefore, here, we aimed to test the clinical effects of a vaccine using glutaraldehyde-fixed human umbilical vein endothelial cells (HUVECs). Six patients with recurrent malignant brain tumours and three patients with metastatic colorectal cancer received intradermal injections of 5 x 10(7) HUVECs/dose (in total 230 vaccinations). ELISA and flow cytometry revealed immunoglobulin response against HUVECs' membrane antigens. ELISPOT and chromium-release cytotoxicity assay revealed a specific cellular immune response against HUVECs, which were lysed in an effectors:targets ratio-dependent manner. Gadolinium-contrasted MRI showed partial or complete tumour responses in three malignant brain tumour patients. Except for a DTH-like skin reaction at the injection site, no adverse effect of vaccination could be observed. our results suggest that the endothelial vaccine can overcome peripheral tolerance of self-angiogenic antigens in clinical settings, and therefore should be useful for adjuvant immunotherapy of cancer. (c) 2007 Elsevier Ltd. All rights reserved

The prediction of the cellular direction of metabolic pathways toward either DNA synthesis or DNA methylation is crucial for determining the susceptibility of cancers to antimetabolites such as fluorouracil (5-FU). We genotyped the methylenetetrahydrofolate reductase (MTHFR) gene in NCI-60 cancer cell lines, and identified the methylation status of 24 tumor suppressor genes using methylation-specific multiplex ligation-dependent probe amplification. The susceptibility of the cancer cell lines to seven antimetabolites was then determined. Cells homozygous for CC at MTHFR-A1298C were significantly more sensitive to cyclocytidine, cytarabine (AraC) and floxuridine than those with AA or AC (p=0.0215, p=0.0166, and p=0.0323, respectively), and carried more methylated tumor suppressor genes (p=0.0313). Among the 12 tumor suppressor genes which were methylated in >25% of cancer cell lines, the methylation status of TIMP3, APC and IGSF4 significantly correlated with sensitivity to pyrimidine synthesis inhibitors. In particular, cells with methylated TIMP3 had reduced mRNA levels and were significantly more sensitive to aphidicolin-glycinate, AraC and 5-FU than cells with unmethylated TIMP3. We speculate that MTHFR-A1298C homozygous CC might direct the methylation rather than the synthesis of DNA, and result in the methylation of several tumor suppressor genes such as TIMP3. These genes could be useful biological markers for predicting the efficacy of antimetabolites.

Background: Epigallocatechin gallate (EGCG), a component of green tea catechin with the strongest biological activity, has been focused in recent years because of its anti-inflammatory and immunomodulatory activities. Dendritic cells (DCs) are professional antigen-presenting cells, capable of priming naive T cells, and play the key roles in the activation of T-cell-mediated immune responses. Objective: We aimed to investigate the effect of EGCG on human monocyte-derived DCs (MODCs) and, consequently, on the T-cell-mediated immune response. Methods: The induction of apoptosis, and the detailed phenotypic and functional changes of MODCs, generated by culture of peripheral blood monocytes in the presence of GM-CSF and IL-4, induced by EGCG was investigated and compared with the effects of dexamethasone. Results: Epigallocatechin gallate induced apoptosis and affected the phenotype of the developing DCs. The expressions of CD83, CD80, CD11c, and MHC class II, which are molecules essential for antigen presentation by DCs, were downregulated by EGCG. EGCG also suppressed the endocytotic ability of immature DCs, whereas dexamethasone-treated DCs had higher endocytotic ability than control DCs. Most importantly, mature DCs treated with EGCG inhibited stimulatory activity toward allogeneic T cells while secreting high amounts of IL-10. Conclusion: Epigallocatechin gallate induces immunosuppressive alterations on human MODCs, both by induction of apoptosis and suppression of cell surface molecules and antigen presentation.

Background: HER family is an attractive target for the treatment of esophageal cancer. The clinical relevance of HER-4 has not been yet characterized. Methods: The expression of HER-4 was immunohistochemically examined in 61 surgically resected esophageal squamous cell carcinomas (ESCC), and the prognostic significance of HER-4 in ESCC was evaluated. Results: HER-4 was positive in the cytoplasm and cell membrane of 51 (84%) tumors, with variable intensity and a heterogeneous distribution, with preferential expression in well or moderately differentiated tumors. Nuclear staining of HER-4 was observed in 37 (61%) cases as well. The membranous/cytoplasmic, but not nuclear, expression of HER-4 was positively correlated with the expression of HER-2 and HER-3. Survival of the HER-4-positive group was significantly better than that of the HER-4-negative group (P < 0.05). Multivariate analysis revealed that I extranuclear expression of HER-4 was independently correlated with increased survival. In contrast, nuclear staining of HER-4 was correlated r with increased T stage, which resulted in a significant reduction in survival in the HER-4 positive group (P < 0.05). Conclusion: Extranuclear HER-4 may have negative effects on the progression of ESCC, whereas nuclear translocation of HER-4 may elicit a tumor-promoting property. Inummohistochemical detection of HER-4 localization is clinically useful to predict the survival of the patients with ESCC.

Aim: Historically, cancer therapy directly targeting tumor cells have yielded suboptimal clinical results, and therefore anti-angiogenic therapy that targets tumor cells indirectly through impairing tumor vasculature is now considered to be one of the novel approaches potentially effective against various types of cancer. In this study, we evaluated whether lysates of endothelium could be effectively pulsed in dendritic cells (DCs), to enhance their anti-tumor effects. Methods: For this purpose, we prepared DCs of BALB/c mouse, incubated them with lysates of autologous or xenogeneic endothelium, and tested their anti-tumor effects in two syngeneic models of colon cancer. Results: DCs pulsed with the respective endothelium lysates significantly inhibited the growth of subcutaneous tumors as well as pulmonary metastases in mice, and their anti-tumor effect was superior to that of unpulsed DCs. Immunohistopathological analysis showed significant decrease in the mean vascular density of tumors, correlating well with the extent of tumor inhibition. In vitro analysis of splenocytes isolated from immunized mice revealed an induction of cytotoxic T lymphocytes and activation of natural killer cells, with a lytic activity against activated endothelium but not tumor cells. In addition, antibodies reacting with activated endothelium, but not tumor cells, were detected in murine sera by ELISA, and their function was confirmed by complement-dependent cytotoxicity assay. Conclusions: Our present results suggest that lysates of endothelium can be effectively pulsed in DCs and enhance their anti-tumor effects through induction of anti-angiogenesis, and therefore should have important clinical implications for adjuvant cancer therapy. (c) 2007 Elsevier Ltd. All rights reserved.

Although some isoprenoids, such as taxans and geranylgeraniol (GGOH), have been reported to have strong anticancer activities, the effect of plaunotol, the isoprenoid extracted from the leaves of Plau-noi, on cancer has not yet been evaluated. Here, we aimed to investigate the effect of plaunotol on gastric cancer cell lines. Three gastric cancer cell lines, namely MKN-45, MKN-74 and AZ-521 were used. Plaunotol was tested at 10, 20, 30 and 40 mu mol/L. Plaunotol dose-dependently inhibited the growth of all gastric cancer cells, dependent on the induction of apoptosis. Caspases-8, -9 and -3, were found to be activated in the apoptotic cells. The expression of Bax protein was increased, but Bcl-2 and Bcl-xL protein expressions were not significantly affected. Plaunotol should be a promising new antitumor agent, and since it is already available for clinical use in Japan, its anticancer properties should be confirmed in clinical trials.

A 55-year-old man developed progressive dysphagia 14 months after palliative colectomy and subsequent systemic chemotherapy for advanced cecal cancer with carcinomatosis peritonei. Radiologic and endoscopic examinations suggested a submucosal tumor in the lower esophagus causing a severe luminal stricture. A self-expanding metal stent was placed for palliation. The prosthesis was effective for several months, but ingrowth of the tumor caused re-stricture of the esophagus. Since his general condition was quite good without any evidence of recurrence of the cecal cancer, we performed bypass surgery for palliation. The pathological appearance of the tumor was compatible with the metastasis of cecal cancer. Our case suggests that a surgical approach can be considered as a therapeutic method for metastatic esophageal tumor, even in patients with advanced cancer, as long as the primary tumor is satisfactorily controlled.

Adiponectin, a circulating peptide hormone produced in adipose tissue, has been shown to be reduced in the plasma of patients with cancer, suggesting that this adipokine may be mechanically involved in the pathogenesis of adiposity-related carcinogenesis. In this study, we examined the expression of adiponectin receptors (AdipoR1 and AdipoR2) and assessed the function of adiponectin in gastric cancer. All of the six gastric cancer cell lines significantly expressed mRNA and protein of both receptors with variable levels. Addition of 30 mu g/mL adiponectin potently induced apoptosis and inhibited the proliferation of AZ521 and HCG27. Down-regulation of either AdipoR1 or AdipoR2 by specific siRNA significantly suppressed the growth inhibitory effects of adiponectin in both cell lines. Moreover, a local injection of adiponectin markedly inhibited the growth of AZ521 inoculated subcutaneously in nude mice. Similarly, the continuous intraperitoneal infusion of adiponectin effectively suppressed the development of peritoneal metastasis of AZ521. Adiponectin negatively regulates the progression of gastric cancer cells possibly through both AdipoR1 and AdipoR2. Although adiponectin was already reported to have antiangiogenic effects, our results suggest that the antitumor effect of adiponectin was, at least partially, dependent on the direct effects on tumor cells.

Lysophosphatidic acid (LPA) is involved in a broad spectrum of biological activities, including wound healing and cancer metastasis. Autotaxin (ATX), originally isolated from a melanoma supernatant as a tumor cell motility-stimulating factor, has been shown to be molecularly identical to lysophospholipase D (lysoPLD), which is the main enzyme in the production of LPA. Although ATX/lysoPLD is known to be widely expressed in normal human tissues, the exact distribution of ATX-producing cells has not been fully investigated. In this study, we evaluated ATX/lysoPLD expression by immunohistochemical staining using a rat anti-ATX mAb in the human gastrointestinal tract and found that submucosal mast cells (MC) highly expressed this enzyme. This was confirmed by immunofluo rescent double staining using mAbs to tryptase and chymase. Then, we isolated MC from human gastric tissue by an immunomagnetic method using CD 117-microbeads and showed that a subpopulation of CD203c-positive MC showed positive staining for intracellular ATX/lysoPLD on flowcytometry. This was confirmed by Western blotting of the isolated cells. Moreover, a significant level of ATX/lysoPLD release could be detected in the culture supernatants of human MC by Western blot analysis. Our data suggest that submucosal MC play significant roles in various aspects of pathophysiology in the gastrointestinal tract by locally providing bioactive LPA through the production of ATX/lysoPLD.

Background. We assessed whether a mixture of hyaluronic acid (HA) and dye can facilitate dye-guided sentinel node (SN) mapping in gastric surgery. Although dye-guided, SN-navigated surgery is clinically applied for the treatment of early gastric cancer, there are still some practical problems. Because dyes are carried out from the SN within 20 to 30 minutes, it is sometimes difficult to detect SNs accurately, especially when they are located in a deep area in obese patients. Methods. Patent blue or ferumoxides, superparamagnetic iron nanocolloids, with or without HA, were injected into the gastrointestinal tract of the pig, and the time course of dye transfer through the lymphatic system of the pig mesentery was assessed. Results. When a mixture of HA and patent blue at a volume ratio of 1:4 was injected into the submucosal layer, the time to stain the SN did not differ from that with patent blue alone; however, HA markedly prolonged the time the blue dye was retained in the SN. Patent blue alone stained the efferent lymphatics of the SN and spread to other lymph nodes within 20 minutes after submucosal injection. At the same time point, in contrast, blue stain was restricted to a part of the SN, and the efferent lymphatics were not stained for 2 hours when patent blue was mixed with HA. When a mixture of HA and ferumoxides was used as the tracer, the ferumoxides were still observed in the mesenteric SN even at 2 days after injection. Iron staining showed that Fe was trapped primarily in cells in the peripheral sinus of the SN, suggesting that the iron nanoparticles were mostly incorporated by phagocytic macrophages in the SN within a few hours. Conclusions. Our data indicate that a mixture with HA prolongs the stay of a dye tracer in the SN and thus enables easy and accurate detection of the SN. HA may be a useful tool to develop a more sophisticated SN mapping technique.

Background and Objectives: Tissue factor (TF), which normally safeguards vascular integrity by inducing hemostasis upon injury, has received widespread attention in the pathogenesis of cancer progression and metastasis. Aberrantly expressed TF in cancer cells has been reported to be associated with advanced stages of malignancy in various cancers. Methods: The expression of TF and microvessel density (MVD) were immunohistochemically evaluated in 207 gastric cancers, and their relationship with clinicopathological features was examined. Results: TF was preferentially expressed (41.8%) in intestinal-type cancer at a significantly higher rate than that in diffuse-type cancer (12.1%, P < 0.0001). The expression of TF was associated with advanced stage of disease and showed a positive correlation with a higher rate of lymphatic and venous invasion and lymphatic metastasis in intestinal-type, but not in diffuse-type carcinoma. Moreover, TF expression was associated with high MVD in the tumor and a worse outcome only in intestinal-type carcinoma. Conclusions: TF may be critically involved in tumor progression in intestinal-type, but not in diffuse-type, gastric carcinoma. The difference in clinical features between these two histological types might be partially dependent on TF expression profile.

Although locoregional recurrence is often observed in the cervicothoracic area even after an esophagectomy with three-field lymph node dissection (3FL), recurrence in the mediastinal lymph nodes is relatively rare. We experienced two cases of solitary recurrence in a posterior mediastinal node ( No 112-ao) after a curative resection for thoracic esophageal cancer. The lymph node recurrence was located in the connective tissue adjacent to the left posterior wall of the thoracic aorta, and thus could not have been removed by the conventional approach of an esophagectomy through a right thoracotomy. These two patients underwent surgical removal of the tumor through left thoracotomy, and survived for 5 years and 1 year without recurrence, respectively. Because the rate of metastasis in this area appears to be low, it is not always necessary to perform complete nodal dissection of the left side of the descending aorta at the initial surgery in cases of thoracic esophageal cancer. However, our experience suggests the importance of periodic computed tomography scans to check for any nodal recurrence in this area, since a surgical resection may be effective when the recurrence is detected as a solitary metastasis.

Background. Among various clinical and pathological findings, lymphatic invasion (Ly) is the strongest risk factor for nodal metastasis in gastric cancer. However, the diagnosis of Ly is subjective and often inaccurate because of the difficulty of detecting lymphatic vessels with conventional hematoxylin and eosin (HE) staining. Methods. The distribution of lymphatics in the normal gastric wall was immunohistochemically characterized using a new selective marker of lymphatic endothelium, D2-40, in surgical specimens resected for early gastric cancer (EGC). Then, Ly in the primary lesion was reevaluated, and the positive (PPV) and negative (NPV) predictive values for nodal metastasis were comparatively examined for Ly detected by HE staining (Ly-HE) and by immunohistochemical staining (Ly-IM) in 131 cases of EGC. Results. D2-40-positive lymphatic vessels were observed in the deep proper mucosal layer, and the lymphatic vessel density (LVD) was extremely high in the muscularis mucosa (MM) layer. The number of Ly-IM-positive cases (15/131) was higher than the Ly-HE-positive cases (10/131). In 48 cases of intestinal-type cancer, Ly-IM had a PPV of 33.3% (2/6) and anNPV of 100% (42/42), which was more accurate than the corresponding figures for Ly-HE (25% and 98%, respectively). In contrast, the accuracy of Ly-IM was similar to that of Ly-HE in 83 cases of diffuse-type cancer. Conclusion. Lymphatic vessels are most densely distributed in the MM layer in the gastric wall. Immunohistochemical identification of lymphatics is useful to increase the accuracy of diagnosing Ly in resected gastric EGCs. Ly-IM is superior to Ly-HE as a predictor of nodal metastasis, at least for intestinal-type EGC. © 2006 International and Japanese Gastric Cancer Association.

AIM: To examine the expression of leptin and its receptor, OB-R, in normal gastric mucosa and neoplasia. METHODS: By immunohistochemical staining using specific antibodies, we evaluated the expression of leptin and OB-R in 207 gastric carcinomas (100 early and 107 advanced carcinomas) and analyzed their relationship with clinicopathological features. RESULTS: Both normal gastric epithelium and carcinoma cells expressed a significant level of leptin. In cases with OB-R staining, carcinoma cells showed OB-R-positive expression, but the intensity was weaker than that in normal mucosa. The expression of OB-R showed a significant correlation with the level of leptin expression. The expression levels of both leptin and OB-R tended to increase as the depth of tumor invasion or TMN stage increased (P< 0.01). Lymph node metastasis was detected in 49.5% (47/95) of leptin-strong cases and in 50.5% (48/95) of OB-R-positive cases, and the rate was 33% (37/112) in leptin-weak cases and 17% (19/112) in OB-R-negative cases. Both venous and lymphatic invasion also tended to be observed frequently in positive tumors as compared with negative tumors. Interestingly, in the 96 leptin- or OB-R-positive tumors, hematogenous metastasis was detected preoperatively in 3 (3.1%) patients. In contrast, none of the carcinomas that lacked expression of leptin and OB-R showed hematogenous metastasis. CONCLUSION: Overexpression of leptin and expression of OB-R may play a positive role in the process of progression in gastric cancer. Functional upregulation of leptin/OB-R may have a positive role in the development and initial phase of progression in gastric cancer. (C) 2006 The WJG Press. All rights reserved.

Aortoesophageal fistula secondary to a thoracic aortic aneurysm is usually a fatal disease with few survivors reported previously. We encountered 2 consecutive patients who were treated successfully with esophagectomy and in situ aorta reconstruction using cryopreserved homograft that was wrapped completely with omental pedicle flap. For the construction of omental flap, the right gastroepiploic artery was resected at the root and all the vessels entering the greater curvature and the transverse colon were resected at the adherent edges. Because the gastroepiploic arcade is totally preserved, large amounts of omental tissue could be obtained, with an excellent blood supply mainly from the left gastroepiploic artery. This type of omental flap is highly mobile, easily transferred to the left hemithorax, and has enough volume to cover the in situ aortic graft completely including anastomosis lines. Thus, our omental coverage appears to be the most reliable method to prevent postoperative graft infection. (c) 2006 Excerpta Medica Inc. All rights reserved.

Endothelial progenitor cells (EPCs) have been recently found to exist circulating in peripheral blood of adults, and home to sites of neovascularization in peripheral tissues. They can also be differentiated from peripheral blood mononuclear cells (PBMNCs). In tumor tissues, EPCs are found in highly vascularized lesions. Few reports exist in the literature concerning the characteristics of EPCs, especially related to their surface antigen expressions, except for endothelial markers. Here, we aimed to investigate the surface expression of differentiation markers, and the functional activities of early-outgrowth of EPCs (EO-EPCs), especially focusing on their antigen-presenting ability. EO-EPCs were generated from PBMNCs, by culture in the presence of angiogenic factors. These EO-EPCs had the morphological and functional features of endothelial cells and, additionally, they shared antigen-presenting ability. They induced the proliferation of allogeneic lymphocytes in a mixed-lymphocyte reaction, and could generate cytotoxic lymphocytes, with the ability to lyze tumor cells in an antigen-specific manner. The antigen-presenting ability of EO-EPCs, however, was weaker than that of monocyte-derived dendritic cells, but stronger than peripheral blood monocytes. Since EO-EPCs play an important role in the development of tumor angiogenesis, targeting EPCs would be an effective anti-angiogenic strategy. Alternatively, due to their antigen-presenting ability, EO-EPCs can be used as the effectors of anti-tumor immunotherapy. Since they share endothelial antigens, the activation of a cellular immunity against angiogenic vessels can be expected. In conclusion, EO-EPCs should be an interesting alternative for the development of new therapeutic strategies to combat cancer, either as the effectors or as the targets of cancer immunotherapy.

Autotaxin (ATX) is a multifunctional phosphodiesterase originally isolated from melanoma cells as a potent cell motility-stimulating factor. ATX is identical to lysophospholipase D, which produces a bioactive phospholipid, lysophosphatidic acid (LPA), from lysophosphatidylcholine (LPC). Although enhanced expression of ATX in various tumor tissues has been repeatedly demonstrated, and thus, ATX is implicated in progression of tumor, the precise role of ATX expressed by tumor cells was unclear. In this study, we found that ATX is highly expressed in glioblastoma multiforme (GBM), the most malignant glioma due to its high infiltration into the normal brain parenchyma, but not in tissues from other brain tumors. In addition, LPA(1), an LPA receptor responsible for LPA-driven cell motility, is predominantly expressed in GBM. One of the glioblastomas that showed the highest ATX expression (SNB-78), as well as ATX-stable transfectants, showed LPA(1)-dependent cell migration in response to LPA in both Boyden chamber and wound healing assays. Interestingly these ATX-expressing cells also showed chemotactic response to LPC. In addition, knockdown of the ATX level using small interfering RNA technique in SNB-78 cells suppressed their migratory response to LPC. These results suggest that the autocrine production of LPA by cancer cell-derived ATX and exogenously supplied LPC contribute to the invasiveness of cancer cells and that LPA(1), ATX, and LPC-producing enzymes are potential targets for cancer therapy, including GBM.

Background: Abnormal hemostasis in cancer patients has previously been described, however the correlation between the plasma fibrinogen level and cancer metastasis and prognosis has not been reported in a large-scale clinical study. Methods: Preoperative plasma fibrinogen levels were retrospectively examined in 405 patients who underwent surgery for advanced gastric cancer. The association of fibrinogen levels with clinical/pathological findings and clinical outcome was evaluated. Results: There was a positive correlation between plasma fibrinogen levels and the depth of invasion ( p < 0.05). Hyperfibrinogenemia (> 310 mg/dl) was independently associated with lymph node ( Odds Ratio; 2.342, P = 0.0032) and liver ( Odds Ratio; 2.933, P = 0.0147) metastasis, not with peritoneal metastasis in this series. Patients with hyperfibrinogenemia showed worse clinical outcome in T2 gastric cancer, however, there was no correlation of plasma fibrinogen level with prognosis in T3/T4 gastric cancer. Conclusion: Our results might support the idea that hyperfibrinogenemia can augment lymphatic and hematogeneous metastasis of advanced gastric cancer, which is major determinant of the prognosis in T2 gastric cancer. Therefore, in the situation without peritoneal involvement, hyperfibrinogenemia is a useful biomarker to predict the possible metastasis and worse clinical outcome in T2 gastric cancer.

Sulforaphane (SUL), one of the isothiocyanates (ITCs), has recently been focused due to its inhibitory effects on tumor cell growth in vitro and in vivo, which is dependent on the direct effect on cancer cells. In the present study, we aimed to investigate the potential anti-angiogenic effect of SUL and its mechanism of action. Using the human umbilical vein endothelial cells (HUVECs) as a model of angiogenesis, we investigated the effect of SUL on the various steps of angiogenesis, including the proliferation of endothelial cells, tubular formation, and matrix metalloproteinase (MMP) production. Sulforaphane induced a dose-dependent decrease in the proliferative activity of endothelial cells, which was dependent on cell apoptosis. Also SUL inhibited tube formation on matrigel, but did not affect MMP production. The present results demonstrate the anti-angiogenic activity of SUL and its potential use as an anti-cancer drug is suggested. © Springer Science+Business Media B.V. 2006.

Resistance to apoptosis is one of the important determinants of resistance to 5-fluorouracil (5-FU) in colorectal cancer cells. Human Ring-Finger homologous to Inhibitor of apoptosis protein type (hRFI) is a newly discovered gene that has been shown to inhibit death receptor-mediated apoptosis in colorectal cancer cells. However, the molecular mechanism of the inhibition of apoptosis is presently unknown. In order to investigate the molecular function of hRFI in the regulation of 5-FU-induced apoptosis in colorectal cancer cells, HCT116 cells were stably transfected with hRFI or LacZ as a control. hRFI overexpression resulted in cellular resistance to 5-FU through an inhibition of the mitochondrial apoptotic pathway and specific upregulation of Bcl-2 and Bcl-XL. Futhermore, hRFI overexpression resulted in the activation of nuclear factor-kappa B (NF-kappa B). Inhibition of NF-kappa B effectively reversed the resistance to apoptosis as well as the upregulation of Bcl-2 and Bcl-XL in the hRFI transfectant, indicating that the activation of NF-kappa B is the key mechanism for all these findings. Overexpression of hRFI in SW480 and COLO320 colorectal cancer cells similarly resulted in resistance to 5-FU with the activation of NF-kappa B and up regulation of Bcl-2 and Bcl-XL. hRFI might be a novel therapeutic target for gene therapy in colorectal cancer.

Background. Lysophosphatidic acid (LPA) is a lipid mediator of diverse effects on various cells. LPA is well known to induce phosphorylation of the epidermal growth factor receptor (EGFR), which is termed transactivation, in some cell types. In this study, we investigated the contribution of EGFR transactivation in LPA-induced responses in colon cancer DLD1 cells. Materials and methods. Immunoprecipitation was performed to investigate whether LPA induced EGFR phosphorylation. Then, we investigated LPA-induced migration and IL-8 secretion in DLD1 cells. Migration was measured in a modified Boyden chamber and IL-8 secretion was measured by ELISA. In these experiments we used an EGFR inhibitor, AG1478 or matrix metalloproteinase (MMP) inhibitor, GM6001. Results. Immunoprecipitation analysis revealed that LPA induced a significant level of tyrosine phosphorylation of EGFR in DLD1 cells. The LPA-induced phosphorylation of EGFR was almost completely abrogated by either AG1478 or GM6001. LPA induced significant migration and IL-8 secretion in DLD1, both of which were significantly inhibited by AG1478 or GM6001. However, the inhibitory effects were only partial (migration; 29% +/- 2%, 32 +/- 13% inhibition, IL-8 secretion; 33% +/- 1%, 26% +/- 5% inhibition, respectively). Conclusion. These results clearly indicate that LPA acts upstream of EGFR and compensates the EGF signal and antagonism of the EGF signal cannot completely block tumor progression in colon cancer cells. Blockade of the LPA signal may have clinical significance in the treatment of colon cancer. (c) 2005 Elsevier Inc. All rights reserved.

At a university hospital in Japan, the introduction of prospective surveillance and subsequent interventions was effective in reducing the rate of surgical site infection associated with elective colorectal surgery from 27.5% to 17.8% of surgeries. Japan should both recognize the importance of broader surveillance for surgical site infection and establish its own nationwide surveillance database.

Id genes (inhibitor of DNA binding/differentiation) play important roles in tumour growth. We have previously described crucial roles of Id gene over-expression in endothelial cells for tumour angiogenesis. Here, we have evaluated direct effects of Id gene down-regulation on tumour cells, namely on cell proliferation, motility, and adhesion to lung microvasculature during haematogenous metastasis. For this purpose, Id genes were stably down-regulated by RNA interference in human colorectal cancer cells. These cells showed delayed proliferation, inhibited motility and decreased expression of integrin alpha 6 and consequently reduced adhesion to lung microvasculature in mice. Static adhesion assays and laminar flow assays revealed decreased laminin binding capacity of these cells, and blocking experiments confirmed that it could be attributed to decreased expression of integrin alpha 6. The present results indicate important roles of Id genes in tumour cells during early steps of haematogenous metastasis and suggest dual effects from their therapeutic inhibition. (c) 2005 Elsevier Ltd. All rights reserved.