Yoshihito Souma

An enhanced risk-group stratification system for more practical prognostication of clinically malignant gastrointestinal stromal tumors

BackgroundRecent breakthroughs regarding the oncogenesis of gastrointestinal stromal tumors (GISTs) have led to the wider use of imatinib mesylate in the treatment of advanced GISTs. However, the role of imatinib in an adjuvant setting has yet to be established, mainly owing to the lack of an accurate system to prognosticate recurrences and/or metastases. The aims of this study were to identify factors prognostic for an unfavorable postoperative outcome, and to enhance the current NIH-consensus risk-group stratification system (Fletchers system).MethodsA retrospective review was conducted in 303 consecutive patients who had undergone surgical resection of primary GISTs during the study period (1987–2003). In addition to Fletchers system, which is based on morphologic variables (tumor size and mitotic count), with four risk groups: very low risk, low risk, intermediate risk, and high risk, the predictive potential of any major preoperative, intraoperative, or postoperative clinical factor was statistically evaluated.ResultsIn addition to tumor size and mitosis, four operative variables were found to affect disease-free survival: peritoneal dissemination, metastasis, invasion, and tumor rupture. Patients presenting with at least one of these “clinically malignant factors” had an unfavorable outcome (i.e., they were potential candidates for adjuvant therapy). We therefore modified Fletchers system by adding a new patient group, termed the “clinically malignant group,” (patients having at least one of the “clinically malignant factors”). With this modification, the outcomes of patients in the “new” very-low-risk and low-risk groups remained favorable, but the outcomes of patients in the “clinically malignant group” and the “new” high-risk group bceame unfavorable.ConclusionThis modified Fletchers system, enhanced by the addition of “clinically malignant factors,” can distinguish patients with a possible unfavorable outcome from those who require no therapy other than surgery. Patients in the “clinically malignant group” could be potential candidates for adjuvant therapy using imatinib.

Intra-abdominal textiloma. A retained surgical sponge mimicking a gastric gastrointestinal stromal tumor: Report of a case

We describe a unique case of intra-abdominal textiloma (granuloma due to a retained foreign body), which mimicked a gastric tumor on preoperative imaging studies. A 78-year-old asymptomatic patient with a past history of a gastrectomy was referred for evaluation of an intra-abdominal mass lesion, which was incidentally observed on a computed tomography (CT) scan. Repeated CT with a higher resolution demonstrated a 5-cm heterogeneously enhanced mass with a distinct feeding artery. These findings were all compatible with a tumorous lesion originating in the gastric remnant, most likely gastric gastrointestinal stromal tumor. A diagnosis of textiloma was immediately made during surgery, and it was confirmed pathologically postoperatively. The feeding artery that appeared on CT images, which was a major reason for the false diagnosis, was considered to have resulted from a slow but continuous inflammation reaction around the retained surgical sponge. Surgeons should therefore always take the possibility of textilomas into consideration even with typical tumorous characteristics on preoperative imaging studies, especially in patients with a history of prior abdominal surgery.

Transvaginal endoscopic partial gastrectomy in porcine models: the role of an extra endoscope for gastric control

BackgroundTransvaginal natural orifice translumenal endoscopic surgery (NOTES) gastrectomy is technically challenging, because wide perigastric dissection under appropriate tissue triangulation is unfeasible with current endoscopic instruments alone. The aim of this study was to investigate the feasibility of transvaginal NOTES gastrectomy with the use of an extra endoscope as a retracting device of the stomach.MethodsThis acute in vivo feasibility study was performed under the approval of the Institutional Animal Care and Use Committee (IACUC). Four female 40-kg pigs received general anesthesia and underwent transvaginal endoscopic partial gastrectomy. Under laparoscopic guidance, the uterus was fixed anteriorly and transvaginal access was established in a standard fashion. The perigastric ligaments were dissected with needle knife/insulation-tipped electrosurgical knife (IT) via transvaginally placed double-channel endoscope. This step was assisted with the second, CO2-insufflating endoscope advanced in the stomach (i.e., so-called endoscopic gastric control). A linear stapling device with a flexible shaft was then passed transvaginally, and the anterior gastric wall was partially resected. The specimen was isolated and retrieved through the vagina. Concluding endoscopy was carried out to confirm the absence of mucosal damage due to endoscopic gastric control. This was further confirmed at necropsy immediately after sacrifice.ResultsAll animals underwent successful transvaginal NOTES gastrectomy. Endoscopic gastric control greatly facilitated perigastric dissection by providing appropriate tissue countertraction on the ligaments. Use of transabdominal (laparoscopic) graspers was thus minimized. There were no intraoperative complications directly related to use of the primary (transvaginal) endoscope or the additional (gastric) endoscope. Distention of downstream bowel after gastric insufflation was minimal with CO2. No major injuries were noted on gastric mucosa at postmortem investigations.ConclusionsTransvaginal NOTES partial gastrectomy is feasible in porcine models. Use of an extra endoscope to retract the stomach is effective to minimize transabdominal assistance. Further studies on human subjects are necessary to establish this as a safe and attractive ancillary technique in NOTES.

Current limitations in endoscopic CO2 insufflation for NOTES: flow and pressure study

BACKGROUND Natural orifice transluminal endoscopic surgery (NOTES) requires fast and steady CO₂ insufflation into the intraluminal and intra-abdominal spaces through a flexible endoscope. However, an optimal endoscopic insufflation system has yet to be determined. OBJECTIVE To verify the performances of 2 currently available CO₂ insufflators in an experimental NOTES setting: (1) an automatic pressure-regulated surgical insufflator (UHI-3) and (2) a manual endoscopic insufflator (UCR). DESIGN An inanimate bench study followed by an acute animal experiment. SETTING Osaka University and Olympus Research and Development Department. MAIN OUTCOME MEASUREMENTS The UHI-3 or UCR was connected to an endoscope of differing length and diameter via an insufflating line of differing length and diameter. The flow rates at the tip of the endoscope (bench test), the time to establish pneumoperitoneum, and the time to re-establish pneumoperitoneum after forceful suction (porcine model) were obtained. RESULTS The UHI-3 failed to feed CO₂ through an insufflating channel but fed CO₂ via a working channel but required a large channel (>3 mm) and a wide insufflating line (>7 mm) to accomplish an acceptable flow rate. UCR fed CO₂ through the insufflating channel; however, the time taken to establish pneumoperitoneum and the time taken to re-establish pneumoperitoneum after forceful suction were longer compared with the time taken for UHI-3 insufflation via the working channel or laparoscopic cannula. LIMITATIONS Bench/animal study with small sample numbers; no human trial. CONCLUSIONS The currently available CO₂ insufflators are not optimal for NOTES. Modification of an endoscopic insufflation system and/or development of a dedicated overtube with an insufflating function are therefore essential.

The role of intraoperative carbon dioxide insufflating upper gastrointestinal endoscopy during laparoscopic surgery

BackgroundIntraoperative endoscopy (IOE) is a useful adjunct during laparoscopic gastrointestinal (GI) surgery. However, one potential hazard of IOE is a prolonged bowel distension due to insufflated air, which may cause obstructed surgical exposure and increased postoperative abdominal pain. Recently, carbon dioxide (CO2), with its rapid absorptive nature, has been proven effective to minimize prolonged bowel distension in ambulatory/intraoperative colonoscopy. The objectives were to assess the feasibility, safety, and efficacy of CO2-insufflating upper GI IOE during laparoscopic surgery.MethodsA historical comparison study was performed on the initial ten consecutive patients who underwent CO2-insufflating upper GI IOE (CO2-IOE) during laparoscopic surgery. The control group consisted of the past 12 consecutive patients who underwent conventional air-insufflating upper GI IOE (air-IOE) during laparoscopic surgery. The following parameters were compared between the two groups: (1) patient demographics; (2) feasibility (% completion of IOE); (3) safety (complications related to IOE, impacts on cardiopulmonary status, including systemic blood pressure, heart rate, and end-tidal CO2); (4) efficacy (postoperative residual intestinal gas, time to resume oral intake, and bowel movement). The amounts of post-IOE residual intestinal gas were evaluated and classified on the immediate postoperative abdominal radiographs in a blinded manner.ResultsPatient demographics were comparable between the two groups. IOE was completed in both groups without complications. Adverse effects on cardiopulmonary status were not observed during simultaneous intraperitoneal and intraluminal CO2 insufflation. In the air-IOE group, one patient was converted to open surgery because of inadequate surgical exposure from prolonged distension of the downstream bowel. The patients in the CO2-IOE group had significantly lower grade of postoperative bowel distension than the control group. Postoperative oral intake was resumed earlier in the CO2-IOE group.ConclusionCO2-insufflating upper GI IOE during laparoscopic surgery is feasible, safe, and has a practical advantage in minimizing post-IOE bowel distension compared with conventional air-insufflating upper GI IOE.

Laparoscopic Heller-Dor surgery for esophageal achalasia: impact of intraoperative real-time manometric feedback on postoperative outcomes.

Background: Laparoscopic Heller myotomy with Dor fundoplication (LHD) is one of the most established surgical procedures for esophageal achalasia. Preoperative esophageal manometry has been reported as useful to evaluate lower esophageal sphincter (LES) pressure. However, the feasibility, safety, and impact of its intraoperative use have not been fully evaluated, especially when enhanced with real-time 3-D pressure imaging. Methods: LHD was attempted on 24 consecutive patients with esophageal achalasia. Manometry was performed at 3 time points during LHD: before myotomy, after myotomy, and after fundoplication. Investigations included esophagography, manometry, and 24-hour esophageal pH monitoring in the preoperative, short-term (0–5 months) and long-term (1–3 years) follow-up periods. Results: The 3-D intraoperative manometric images were presented to the surgical crew on a monitor screen immediately after each measurement in all attempted cases (n = 13). Any residual high pressure zone of the LES was easily recognized and resolved with additional myotomy. Postoperative esophagographies showed resolution of esophageal dilatation. Manometric examination revealed significant reduction of LES pressure in the short-/long-term follow-up periods. PH monitoring showed no increase in acid reflux. Overall outcomes were satisfactory (symptom relief = 95%). Conclusion: Intraoperative manometry with real-time pressure feedback is a feasible, safe, and useful adjunct in LHD.

Aberrant expression of glycosylation in juvenile gastrointestinal stromal tumors.

Most adult gastrointestinal stromal tumors (GIST) are thought to be caused by activating mutations in the KIT or PDGFRA gene. However, many juvenile GIST lack either mutation and are considered to develop with a different pathogenesis. To investigate the molecular characteristics of juvenile GIST, we analyzed the proteome difference in phosphorylated protein between adult and juvenile GIST. Eleven GIST samples (seven adult cases and four juvenile cases lacking either mutation) were analyzed by using immunostaining and LC‐MS/MS. Comparative analysis of tyrosine‐phosphorylated protein levels showed that juvenile GIST possessed phosphorylated KIT in spite of lacking mutation in the KIT gene. Moreover, downstream signals of KIT were also activated as in adult GIST. Although, SDS‐PAGE gels showed that there was a difference of each KIT bands between adult and juvenile GIST, they became the same after removal of N‐glycans or sialic acids. Moreover, one of the most typical enzymes, ST6Gal1, which transfers Neu5Ac residues in α2‐6 linkage to Gal β1‐4GlcNAc units on N‐glycans, is significantly less expressed in juvenile GIST. This suggests that the difference in KIT is generated by post‐translational modification and may play a role in the progression of juvenile GIST.

Abstract 722: Gene therapy for peritoneal dissemination model of gastric cancer using SOCS-1 by Adenoviral Vector

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Objective: The peritoneal metastasis is one of the most common recurrence style of gastric cancer (GC) and an effective treatment for their patients has not been established. Suppressor of cytokine signaling-1 (SOCS-1) is a negative regulator of various cytokine signaling and has been recently focused on as a therapeutic target in treatment for cancer. The aim of this study was to evaluate the effect with the enforced SOCS-1 expression by adenoviral vector (AdSOCS-1). METHODS: We evaluated the therapeutic effect of SOCS-1 in 6 GC cell lines with proliferation assay. Moreover, we examined the mechanism of antitumor effect of SOCS-1 focusing on the cell signalling and cell cycle in vitro. In vivo study, we evaluated the therapeutic effect in mice model. MKN45-Luc cell line was intraperitoneally injected into ICR nu/nu mice. And, we evaluated the peritoneal dissemination by the in vivo imaging system using Xenogen IVIS ® Imaging System. We treated these mice using the intraperitoneal injection of AdSOCS-1, twice a week for 4weeks. We evaluated the peritoneum dissemination by the photon intensity with time course repeatedly. Finally, we examined these tumor specimen pathologically and the overall survival (N=22). RESULTS: In 3 GC cell lines among 6 GC cell lines, AdSOCS-1 suppressed the proliferation. SOCS-1 showed an anti-proliferative potential in the GC cell proliferation via the inhibition of JAK/STAT and p38 MAPK signaling pathways and also induced apoptosis in vitro. Additionally, SOCS-1 is proven to influence the cell cycle in G2/M phase activating the Chk2 in a JAK/STAT independent manner. In Xenograft peritoneal dissemination model, the total count of photon after therapy in AdSOCS-1 group was significantly lower than that in control group. By TUNEL immunohistochemical analysis, tumor specimen in AdSOCS-1 group included more apoptosis area comparing with that in the control group. To assess whether overexpression of SOCS-1 also reduced proliferation of MKN-45 cells in vivo, Ki-67 expression was determined by immunohistochemistry. AdSOCS-1 group showed decreased Ki-67 positive cells compared to control group. We compared the overall survival of the peritoneal dissemination mice in two groups. AdSOCS-1 group showed better outcome than control group significantly. CONCLUSIONS: Our results indicated that SOCS-1 inhibited the progression of gastric cancer in Xenograft peritoneal dissemination model. SOCS-1 can be a novel therapeutic application for peritoneal metastasis in gastric cancer. Citation Format: Rie Nakatsuka, Tsuyoshi Takahashi, Satoshi Serada, Minoru Fujimoto, Yoshihito Souma, Yasuhiro Miyazaki, Yukinori Kurokawa, Makoto Yamasaki, Hiroshi Miyata, Kiyokazu Nakajima, Shuji Takiguchi, Masaki Mori, Yuichiro Doki, Yuichiro Doki, Tetsuji Naka. Gene therapy for peritoneal dissemination model of gastric cancer using SOCS-1 by Adenoviral Vector. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 722. doi:10.1158/1538-7445.AM2014-722

Abstract 1970: SOCS-1,-3 gene delivery in gastric cancer cells induces a potent anti-proliferative effect via the suppression of JAK/STAT and P38 MAPK signaling pathways

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL BACKGROUND:Enhanced activation of inflammatory cytokines signaling transductions have been suggested as a driving force in the development of gastric tumors. The suppressor of cytokine signaling (SOCS) family proteins are important negative regulator of proinflammatory cytokine signals and have been reported to be frequently silenced by DNA methylation of CpG islands in gastric cancer (GC). The aim of this in vitro assessment was to evaluate the role of SOCS-1 and SOCS-3 in the proliferation of GC cell through regulating cytokine signaling pathways. MATERIAL AND METHODS:Six GC cell lines (NUGC3, AGS, MKN45, NUGC4, MKN7, and MKN74) were used in this study. Methylation status of SOCS-1/-3 was assessed by methylation specific PCR. The concentrations of IL-6 in the cell culture supernatant was measured by ELISA. Adenovirus vectors encoding either SOCS-1 or SOCS-3 were constructed for gene delivery to GC cells. The status of activated kinases and downstream proteins were determined by Western blot analysis. Anti-proliferative effects in GC cells were assessed by WST-8 assay. RESULTS: In six GC cell lines used in our study, SOCS-1 and SOCS-3 genes were methylated except one cell line, and two cell lines (NUGC3, AGS) showed elevated endogenous IL-6 production with constitutively phosphorylated STAT3. Unexpectedly, anti-IL-6R antibody did not affect both of the cell proliferation and the status of phosphorylated STAT3 in these two cell lines. In contrast, adenovirus-mediated SOCS-1 /-3 gene delivery markedly reduced cell proliferation of these cells. The anti-proliferative effect of SOCS-1/-3 correlated with decreased levels of the activation of STAT3 and p38 MAPK. Cell proliferation assay confirmed that the blockade of JAK/STAT and p38 MAPK signaling pathways also reduced cell proliferation of these cell lines. CONCLUSIONS: Our results indicated that the DNA methylation of SOCS-1/-3 may be associated with GC proliferation, and highlighted an anti-proliferative potential of SOCS-1/-3 through the inhibition of JAK/STAT and p38 MAPK signaling pathways independently IL-6 signaling. Thus, DNA methylation of SOCS-1/-3 can be a molecular marker of GC progression, and their forced expression may represent a novel therapeutic application as a multi-growth signal inhibitor for GC treatment. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1970. doi:10.1158/1538-7445.AM2011-1970