Efficacy of the traction method for gastric endoscopic submucosal dissection: a randomized controlled trial (with videos).

BACKGROUND AND AIMS: To overcome the technical difficulties associated with gastric endoscopic submucosal dissection (ESD), a novel traction device that can alter the direction of traction was developed. This study compared the efficacy and safety of conventional ESD versus those of traction-assisted gastric ESD. METHODS: Patients with a single gastric epithelial neoplasm were randomized to receive conventional (n = 75) or traction-assisted (n = 73) gastric ESD. The primary outcome was ESD procedure time. RESULTS: There were no differences between the conventional and traction-assisted groups with respect to treatment results or adverse events. The mean procedure time was similar for both groups (78.9 vs 88.3 minutes, respectively; P = .3); however, times for the traction device tended to be shorter for lesions in the lesser curvature of the upper or middle stomach (84.6 vs 123.2 minutes; P = .057). CONCLUSIONS: Traction-assisted ESD for lesions in the lesser curvature of the upper or middle stomach were shorter, thereby reducing the procedure time of conventional ESD. (Clinical trial registration: University Hospital Medial Information Network Clinical Trials Registry, identifier 000044450.).

[Three Cases of Preoperative Chemotherapy(FOLFOXIRI plus Bevacizumab)for Locally Advanced Colorectal Cancer with Urinary Bladder Invasion].

Radical cystectomy for locally advanced colorectal cancer with urinary bladder invasion significantly reduces the quality of life in exchange for a cure. We performed preoperative chemotherapy with FOLFOXIRI plus bevacizumab for 3 patients with locally advanced colorectal cancer with urinary bladder invasion to avoid radical cystectomy and to achieve local control for urinary bladder preservation. Grade 3 neutropenia was observed in 2 patients as an adverse reaction to the preoperative chemotherapy, but all 3 patients showed good tumor regression. All 3 patients underwent laparoscopic high anterior rectal resection and partial cystectomy, and all were able to undergo R0 resections with urinary bladder preservation. One patient had anastomotic leakage as a postoperative complication. One patient had local recurrence in the urinary bladder, and 2 had recurrence with peritoneal dissemination during their postoperative courses. Preoperative chemotherapy(FOLFOXIRI plus bevacizumab)for locally advanced colorectal cancer with urinary bladder invasion is considered to be a useful treatment option because of its potential for tumor shrinkage and bladder preservation.

Hypoxia-Induced CD36 Expression in Gastric Cancer Cells Promotes Peritoneal Metastasis via Fatty Acid Uptake.

BACKGROUND: The lipid scavenger receptor cluster of differentiation 36 (CD36) has been shown to have a pro-metastatic function in several cancers. Adipose tissue, a favorable site for peritoneal metastasis (PM) from gastric cancer (GC), promotes this process by providing free fatty acids (FFAs); however, the role of CD36 in PM progression from GC remains to be elucidated. MATERIALS AND METHODS: We evaluated CD36 expression in the GC cells under various conditions. CD36 overexpressing (CD36OE) MKN45 cells were prepared and their migration and invasive properties were assessed. A PM mouse model was used to investigate the biological effects of palmitic acid (PA) and CD36. Furthermore, we examined the clinical role of CD36 expression in 82 human PM samples by immunohistochemical staining. RESULTS: Hypoxia markedly increased CD36 expression in GC cells. In normoxia, only CD36OE MKN45 cells treated with PA showed an increase in migration and invasion abilities. An increased expression of active Rac1 and Cdc42 was observed, which decreased following etomoxir treatment. Conversely, hypoxia increased those capacities of both vector and CD36OE MKN45 cells. In a mouse model transplanted with CD36OE MKN45 cells, more peritoneal tumors were observed in the high-fat diet group than those in the normal diet group. In clinical samples, 80% of PM lesions expressed CD36, consistent with hypoxic regions, indicating a significant association with prognosis. CONCLUSION: Our findings indicate that a hypoxia in the peritoneal cavity induces CD36 expression in GC cells, which contributes to PM through the uptake of FFAs.

Impact of preoperative docetaxel, cisplatin, and 5-fluorouracil (DCF) therapy on degree of malignant esophageal stenosis.

BACKGROUND: Malignant esophageal stenosis is a common and severe complication of advanced esophageal cancer that can be a serious problem in the continuation of chemotherapy and other anticancer treatments. The impact of chemotherapy regimens on the degree of improvement in esophageal stenosis is unknown. In this study, we focused on the impacts of chemotherapy on the direct anticancer effects, and in the improvement of malignant stenosis. METHODS: Patients who underwent radical esophagectomy after chemotherapy, either adjuvant 5-fluorouracil and cisplatin (FP) or docetaxel, cisplatin, and 5-fluorouracil (DCF) regimen, were included. We assessed the length of the cancerous stenosis, the width of the narrowest segment, and the size of the intraluminal area in the stenotic segment by fluoroscopy, and compared the differences before and after chemotherapy. In addition, we evaluated the dysphagia score (Mellow-Pinkas scoring system) as the evaluation of patients' symptoms. The antitumor effects of chemotherapy were also investigated. RESULTS: A total of 81 patients were enrolled: 50 were treated with FP, and 31 were treated with DCF. The expansion rate in the length of the narrowest part was significantly increased in the DCF group compared with the FP group. Furthermore, the stenosis index (intraluminal stenotic area/stenotic length) was significantly increased in the DCF group compared with the FP group (112% vs 96%, P = 0.038). Dysphagia score after chemotherapy significantly improved in the DCF group compared to the FP group (P = 0.007). The response rates were 60% in the FP group and 67.7% in the DCF group. Effective histopathological response (improvement to grade 2 or 3) was 24% in the FP group and 38.8% in the DCF group. CONCLUSION: DCF therapy is more effective than FP treatment in the improvement of malignant esophageal stenosis.

Suppression of galectin-4 attenuates peritoneal metastasis of poorly differentiated gastric cancer cells.

BACKGROUND: Peritoneal dissemination, most often seen in metastatic and/or recurrent gastric cancer, is an inoperable condition that lacks effective treatment. The use of molecular targeted drugs is also limited; therefore, identifying novel therapeutic targets and improving our understanding of this metastatic cancer are an urgent requirement. In this study, we focused on galectin-4, which is specifically expressed in poorly differentiated cells with high potential for peritoneal dissemination. METHODS: We knocked out the galectin-4 gene in NUGC4 cells using CRISPR/Cas9-mediated genome editing. Proliferation and peritoneal cancer formation in knockout cells were compared with those in wild-type and galectin-4 re-expressing cells. Western blotting and proximity ligation assays were performed to identify associated molecules affected by the expression of galectin-4. The effect of galectin-4 knockdown on cell proliferation and peritoneal metastasis was studied using a specific siRNA. Expression of galectin-4 in peritoneal metastatic tumors from 10 patients with gastric cancer was examined by immunohistochemistry. RESULTS: Suppression of galectin-4 expression reduced proliferation and peritoneal metastasis of malignant gastric cancer cells. Galectin-4 knockout and knockdown reduced the expression of activated c-MET and CD44. Galectin-4 was found to interact with several proteins on the cell surface, including CD44 and c-MET, via its carbohydrate-binding ability. Immunohistochemistry showed galectin-4 expression in peritoneal metastatic tumor cells in all patients examined. CONCLUSIONS: We clarified the role of galectin-4 in the development of peritoneal dissemination of poorly differentiated gastric cancer cells. Our data highlight the diagnostic and therapeutic potential of galectin-4 in the peritoneal dissemination of gastric cancer.

Endoscopic N-butyl-2-cyanoacrylate and ethanolamine oleate injection is equivalent to balloon-occluded retrograde transvenous obliteration for preventing gastric variceal bleeding.

OBJECTIVES: Endoscopic injection sclerotherapy (EIS) is effective for temporary hemostasis, but EIS and balloon-occluded retrograde transvenous obliteration (BRTO) have been reported as effective for secondary prophylaxis of gastric varices (GV) bleeding. This study retrospectively compared EIS and BRTO in patients with GV in terms of the efficacy for secondary prevention of GV bleeding and effects on liver function. METHODS: From our database of patients with GV who underwent EIS or BRTO between February 2011 and April 2020, a total of 42 patients with GV were retrospectively enrolled. The primary endpoint was the bleeding rate from GV, which was compared between EIS and BRTO groups. Secondary endpoints were liver function after treatment and rebleeding rate from EV, compared between EIS and BRTO groups. Rebleeding rates from GV and EV and liver function after treatment were also compared between EIS-ethanolamine oleate (EO)/histoacryl (HA) and EIS-HA groups. RESULTS: Technical success was achieved for all EIS cases, but two cases were unsuccessful in the BRTO group and underwent additional EIS. No significant differences in bleeding rates or endoscopic findings for GV improvement were seen between EIS and BRTO groups. Liver function also showed no significant difference in the amount of change after treatment between groups. CONCLUSION: EIS therapy appears effective for GV in terms of preventing GV rebleeding and effects on liver function after treatment. EIS appears to represent an effective treatment for GV.

Analysis of factors associated with operative difficulty in thoracoscopic esophageal cancer surgery in the left-decubitus position: a single-center retrospective study.

BACKGROUND: The degree of difficulty in the overall procedure and forceps handling encountered by surgeons is greatly influenced by the positional relationship of intrathoracic organs in minimally invasive esophagectomy. This study aimed to identify the anatomical factors associated with the difficulty of minimally invasive esophagectomy assessed by intraoperative injuries and postoperative outcomes. METHODS: Minimally invasive esophagectomy in the left-decubitus position was performed in 258 patients. We defined α (mm) as the anteroposterior distance between the front of the vertebral body and aorta, ß (mm) as the distance between the center of the vertebral body and center of the aorta, and γ (degree) as the angle formed at surgeon's right-hand port site by insertion of lines from the front of aorta and from the front of vertebrae in the computed tomography slice at the operator's right-hand forceps hole level. We retrospectively analyzed the correlations among clinico-anatomical factors, surgeon- or assistant-caused intraoperative organ injuries, and postoperative complications. RESULTS: Intraoperative injuries significantly correlated with shorter α (0.2 vs. 3.9), longer ß (33.0 vs. 30.5), smaller γ (3.0 vs. 4.3), R1 resection (18.5% vs. 8.3%), and the presence of intrathoracic adhesion (46% vs. 26%) compared with the non-injured group. Division of the median values into two groups showed that shorter α and smaller γ were significantly associated with organ injury. Longer ß was significantly associated with postoperative tachycardia onset, respiratory complications, and mediastinal recurrence. Furthermore, the occurrence of intraoperative injuries was significantly associated with the onset of postoperative pulmonary complications. CONCLUSIONS: Intrathoracic anatomical features greatly affected the procedural difficulty of minimally invasive esophagectomy, suggesting that preoperative computed tomography simulation and appropriate port settings may improve surgical outcomes.

[A Case of Postoperative Recurrence of Bilateral Breast Cancer in Which Stable Disease Condition Was Achieved by Olaparib].

The patient is a 51-year-old female with comorbidity of schizophrenia. At the age of 41, she underwent surgery for bilateral breast cancer. Both sides were of the Luminal type, with Stage ⅢC on the right and Stage 0 on the left. She started to receive adjuvant chemotherapy but it was interrupted according to her wish. Approximately 3 years ago, she developed carcinomatous pleuritis, multiple liver metastases, and bone metastases. Despite receiving chemotherapy, her condition worsened. A BRACAnalysis revealed pathogenic variants in BRCA2. Upon initiating treatment with olaparib, both her liver metastases and carcinomatous pleuritis have shown reductions, and her tumor markers have also started to decline. Approximately 5 months after treatment with olaparib, it has been possible to continue without any side effects. Olaparib has shown good results in patients with germline BRCA1/2 mutation-positive HER2-negative advanced/recurrent breast cancer who have a history of receiving anthracycline and taxane-based therapies. It was considered that even in recurrent breast cancer, the presence or absence of BRCA1/2 mutations should be actively sought even in advanced cases, and the administration of olaparib should be considered.

[A Case of Resection of Right Axillary Accessory Breast Cancer with Skin Invasion].

A 56-year-old female was referred to our hospital for further examination and treatment because of her increasing right axillary mass for 1 year. Based on histological examination diagnosing the right axillary mass as carcinoma and radiological examination showing no evidence of distal metastasis, we decided to perform a radical resection. The patient underwent right axillary mass resection, axillary lymph node dissection, and latissimus dorsi musculocutaneous flap reconstruction. Right-sided breast cancer was diagnosed based on histopathological examination. The diagnosis was similar to that of breast cancer. The patient underwent adjunctive chemotherapy and is currently undergoing endocrine therapy. The incidence of accessory breast cancer is 0.2-0.6% among all breast cancers and is relatively rare. Postoperative adjuvant pharmacotherapy has no consensus. However, endocrine therapy, chemotherapy, and molecular target therapy are performed in cases of conventional breast cancer. Herein, we describe a case of right axillary accessory breast cancer with skin invasion successfully treated with radical resection.

Prognostic value of tumor-infiltrating CD163+macrophage in patients with metastatic gastric cancer undergoing multidisciplinary treatment.

BACKGROUND: The multidisciplinary treatment including induction chemotherapy plus conversion surgery (CS) has attracted attention as a new strategy to improve the outcome of metastatic gastric cancer (MGC). However, it is unclear which patients achieve a good response to chemotherapy and successful CS. Tumor-infiltrating immune cells (TIICs) have been reported to be both prognostic and predictive biomarkers not only in immunotherapy but also in chemotherapy in many cancer types. However, there have been no reports on the usefulness of TIICs as biomarkers in conversion surgery for MGC. The aim of the present study was to evaluate the association between the TIICs and treatment outcome for the multidisciplinary treatment in MGC. METHODS: We retrospectively analyzed 68 MGC patients who received docetaxel plus cisplatin plus S-1 (DCS) therapy between April 2006 and March 2019 in our institute. The number of tumor-infiltrating CD4+, CD8+, Foxp3+lymphocytes, CD68+, CD163+macrophages in pre-treatment endoscopic biopsy samples were evaluated to investigate their predictive value for multidisciplinary treatment. RESULTS: Fifty patients underwent CS following DCS therapy (CS group), whereas 18 patients underwent DCS therapy alone (non-CS group). The median survival time (MST) of CS group was 33.3 months, which was significantly longer than the MST of 9.0 months in non-CS group (p < 0.01). The number of CD163+macrophages was extracted as an independent prognostic factor for overall survival in all patients. There were more cases of high infiltration of CD163+macrophages in non-CS group than in CS group. Furthermore, in CS group, pathological responders to DCS therapy showed low infiltration of CD163+ macrophages, and high infiltration of CD8+lymphocyte. CD163 low group showed a significant prolonged survival compared with CD163 high group in patients who underwent CS (p = 0.02). CONCLUSIONS: The pre-treatment CD163+macrophages infiltration would be a pivotal biomarker for predicting prognosis and pathological response to multidisciplinary treatment among TIICs in MGC. Thus, for patients with low CD163+macrophage infiltration in pre-treatment biopsy sample, diagnostic imaging should be performed frequently during chemotherapy to avoid missing the optimal timing for CS, and CS should be aggressively considered as a treatment option if curative resection is deemed feasible.

Crosstalk between cancer-associated fibroblasts and immune cells in peritoneal metastasis: inhibition in the migration of M2 macrophages and mast cells by Tranilast.

BACKGROUND: The role of tumor-stroma interactions in tumor immune microenvironment (TME) is attracting attention. We have previously reported that cancer-associated fibroblasts (CAFs) contribute to the progression of peritoneal metastasis (PM) in gastric cancer (GC), and M2 macrophages and mast cells also contribute to TME of PM. To elucidate the role of CAFs in TME, we established an immunocompetent mouse PM model with fibrosis, which reflects clinical features of TME. However, the involvement of CAFs in the immunosuppressive microenvironment remains unclear. In this study, we investigated the efficacy of Tranilast at modifying this immune tolerance by suppressing CAFs. METHODS: The interaction between mouse myofibroblast cell line LmcMF and mouse GC cell line YTN16 on M2 macrophage migration was investigated, and the inhibitory effect of Tranilast was examined in vitro. Using C57BL/6J mouse PM model established using YTN16 with co-inoculation of LmcMF, TME of resected PM treated with or without Tranilast was analyzed by immunohistochemistry. RESULTS: The addition of YTN16 cell-conditioned medium to LmcMF cells enhanced CXCL12 expression and stimulated M2 macrophage migration, whereas Tranilast inhibited the migration ability of M2 macrophages by suppressing CXCL12 secretion from LmcMF. In PM model, Tranilast inhibited tumor growth and fibrosis, M2 macrophage, and mast cell infiltration and significantly promoted CD8 + lymphocyte infiltration into the tumor, leading to apoptosis of cancer cells by an immune response. CONCLUSION: Tranilast improved the immunosuppressive microenvironment by inhibiting CAF function in a mouse PM model. Tranilast is thus a promising candidate for the treatment of PM.

Interleukin-17A derived from mast cells contributes to fibrosis in gastric cancer with peritoneal dissemination.

OBJECTIVES: Interleukin-17A (IL-17A) is pro-inflammatory cytokine and acts as profibrotic factor in the fibrosis of various organs. Fibrosis tumor-like peritoneal dissemination of gastric cancer interferes with drug delivery and immune cell infiltration because of its high internal pressure. In this study, we examined the relationship between IL-17A and tissue fibrosis in peritoneal dissemination and elucidated the mechanism of fibrosis induced by IL-17A using human peritoneal mesothelial cells (HPMCs) and a mouse xenograft model. METHODS: Seventy gastric cancer patients with peritoneal dissemination were evaluated. The correlation between IL-17A and fibrosis was examined by immunofluorescence and immunohistochemistry. A fibrosis tumor model was developed based on subcutaneous transplantation of co-cultured cells (HPMCs and human gastric cancer cell line MKN-45) into the dorsal side of nude mice. Mice were subsequently treated with or without IL-17A. We also examined the effect of IL-17A on HPMCs in vitro. RESULTS: There was a significant correlation between IL-17A expression, the number of mast cell tryptase (MCT)-positive cells, and the degree of fibrosis (r = 0.417, P < 0.01). In the mouse model, IL-17A enhanced tumor progression and fibrosis. HPMCs treated with IL-17A revealed changes to a spindle-like morphology, decreased E-cadherin expression, and increased α-SMA expression through STAT3 phosphorylation. Moreover, HPMCs treated with IL-17A showed increased migration. CONCLUSIONS: IL-17A derived from mast cells contributes to tumor fibrosis in peritoneal dissemination of gastric cancer. Inhibiting degranulation of mast cells might be a promising treatment strategy to control organ fibrosis.

Current status of conversion surgery for stage IV gastric cancer.

Palliative chemotherapy with best supportive care is a mainstay for patients with gastric cancer (GC) and distant metastasis. However, with advances in GC chemotherapy, multimodal treatment, including perioperative chemotherapy plus conversion surgery, has attracted attention as a new strategy to improve the outcome of patients with stage IV disease. Conversion surgery is defined as surgical treatment aimed at R0 resection after a good response to induction chemotherapy for tumors originally considered unresectable or marginally resectable for technical and/or oncological reasons. Various biological characteristics differ, depending on each metastatic condition in stage IV GC. The main metastatic pathways of GC can be divided into three categories: lymphatic, hematogenous, and peritoneal. In each category, considerable historical data on conversion surgery have demonstrated the benefits of individualized approaches. However, owing to the diversity of these conditions, a common definition, including the choice of induction chemotherapy, optimal timing of resection, and eligibility for conversion surgery, has not been established among surgical oncologists. Thus, we explore the current and future treatment options by reviewing the literature on this controversial topic comprehensively.

[A Case of an Asymptomatic Coagulopathy after Peritoneovenous Shunt Placement for Malignant Ascites of Gastric Cancer].

The patient was a 61‒year‒old man who had an advanced gastric cancer with peritoneal dissemination. After chemotherapy, intraoperative findings during a total gastrectomy revealed the disappearance of the dissemination nodules. Although adjuvant chemotherapy was performed, the presence of massive ascites led to the recurrence of the peritoneal dissemination 5 months after the surgery. While the chemotherapy regimen was altered, we observed no reduction in malignant ascites. The patient complained of abdominal distention and was admitted to our hospital for symptom management. We performed a cell‒free and concentrated ascites reinfusion therapy(CART)several times. However, symptom management proved difficult; therefore, the patient underwent a peritoneovenous shunt(Denver shunt)placement. After the shunting, we observed no organ injury and improved abdominal distention; however, an asymptomatic coagulopathy was present in the course. Additionally, blood examinations showed increased FDP‒DD and thrombin‒antithrombin complex(TAT). However, 6 months after the shunting, coagulopathy improved and the patient reported the absence of abdominal distention. This report describes a patient with an asymptomatic coagulopathy after Denver shunt placement and evaluated the clinical course by using TAT values.

[Laparoscopy Assisted Subtotal Gastrectomy(Billrothâ Reconstruction)for Gastric Cancer in the Upper Stomach-A Report of Three Cases].

We experienced 3 cases of upper gastric cancer who underwent BillrothⅠ reconstruction in laparoscopy assisted subtotal gastrectomy. Two cases were female and 1 was male. The postoperative course was uneventful in all cases without heartburn, and the surgical margin was negative. The body weight loss rate was 5.8-12.6%, and the short-term results were relatively acceptable. Although the number of cases in this study was small, reconstruction with BillrothⅠ/delta-shaped anastomosis after laparoscopy assisted subtotal gastrectomy were considered to be useful.

[Four Cases of Surgical Treatment for Radiation Enteritis].

Although radiation therapy for pelvic cancer leads to improved outcomes, it may cause radiation enteritis. Radiation enteritis is classified as early and late reaction. Late reaction indicate progressive and irreversible changes caused by ischemic changes of the intestinal mucosa. Severe cases require a surgical treatment, which is challenging because of severe adhesions and a high risk of suture failure. In addition, the postoperative course may be unfavorable in some cases. We performed surgery for 4 radiation enteritis cases; however, the postoperative course was unfavorable in 2 cases because of impaired absorption and ileus of the remaining short bowel. These patients could not eat adequately after discharge; therefore, we needed to explain and make them understand the benefits and disadvantages of radiation therapy.

Optimization of robot-assisted thoracoscopic esophagectomy in the lateral decubitus position.

BACKGROUND: On the introduction of robot-assisted thoracoscopic esophagectomy (RATE), we refined the robotic system application to enhance our surgical experience obtained through thoracoscopic esophagectomy (TE) in the lateral decubitus position (LDP). Herein, we evaluate our methods introduced to optimize RATE in the LDP. METHODS: We performed RATE in the LDP with camera rotation and manual hand control assignment to reproduce the surgical view and manipulation of open esophagectomy. Forty patients underwent RATE between July 2018 and August 2020. After the initial 30 cases (initial RATE group), we optimized the port arrangement and robot settings in the most recent ten cases (recent RATE group). The surgical results of RATE were compared with those of 30 patients underwent TE between April 2014 and May 2019 selected by propensity score-matched analysis based on cStage (TE group). RESULTS: Operative duration was significantly longer in the initial RATE group than the TE group and the recent RATE group. Thoracic blood loss was significantly less in the initial RATE group than the TE group. Console time was significantly shorter in the recent RATE group than the initial RATE group. There was no surgical mortality in RATE and the surgical morbidity rate was similar in the three groups. CONCLUSIONS: Camera rotation and manual hand control assignment during RATE in the LDP reproduced the surgical view and manipulation of open esophagectomy and TE in the LDP. The robotic platform enabled meticulous dissection and reduced blood loss, but was initially time-consuming. Optimization of the port arrangement minimized operative duration.

Expression of c-Met in Primary and Recurrent Hepatocellular Carcinoma.

BACKGROUND: The clinical course of hepatocellular carcinoma (HCC) is complicated, because it often recurs and shows multiple lesions, some of which progress to a more malignant form, shortening the life of the patient. The hepatocyte growth factor receptor c-Met has been shown to play an important role in the pathogenesis of HCC, but the influence of c-Met expression on the clinical course of HCC remains to be fully elucidated. METHODS: We randomly selected and included 600 tumor specimens obtained from the primary and recurrent lesions of 319 HCC cases between 1995 and 2007. The expression of c-Met was determined by immunohistochemistry using archived formalin-fixed paraffin-embedded samples. We analyzed the correlation between c-Met expression and clinical parameters, including survival. In addition, we examined c-Met expression in the malignant transition of HCC in all cases including recurrent lesions. RESULTS: Survival analysis using the multivariate Cox proportional-regression model revealed that the prognosis was significantly better in the primary cases with high c-Met expression than in those with low c-Met expression (hazard ratio 0.159, 95% confidence interval 0.065-0.391; p < 0.001). During the course of recurrence, some cases with high c-Met expression returned to low c-Met expression. Among 40 cases with high c-Met expression, 29 survived more than 2 years after detecting the high c-Met expression. CONCLUSION: High expression of c-Met may be a prognostic factor for a good, rather than a poor, HCC prognosis. The involvement of c-Met expression in the malignant transition of recurrent HCC is obscure.

Established fibrous peritoneal metastasis in an immunocompetent mouse model similar to clinical immune microenvironment of gastric cancer.

BACKGROUND: Peritoneal metastasis (PM) in gastric cancer (GC) is characterized by diffusely infiltrating and proliferating cancer cells accompanied by extensive stromal fibrosis in the peritoneal space. The prognosis of GC with PM is still poor regardless of the various current treatments. In order to elucidate the cause of difficulties in PM treatment, we compared the tumor immune microenvironment (TME) in primary and PM lesions in GC. In addition, a PM model with fibrous stroma was constructed using immunocompetent mice to determine whether its TME was similar to that in patients. METHODS: Immuno-histochemical analyses of infiltrating immune cells were performed in paired primary and PM lesions from 28 patients with GC. A C57BL/6 J mouse model with PM was established using the mouse GC cell line YTN16 either with or without co-inoculation of mouse myofibroblast cell line LmcMF with α-SMA expression. The resected PM from each mouse model was analyzed the immunocompetent cells using immunohistochemistry. RESULTS: The number of CD8+ cells was significantly lower in PM lesions than in primary lesions (P < 0.01). Conversely, the number of CD163+ cells (M2 macrophages) was significantly higher in PM lesions than in primary lesions (P = 0.016). Azan staining revealed that YTN16 and LmcMF co-inoculated tumors were more fibrous than tumor with YTN16 alone (P < 0.05). Co-inoculated fibrous tumor also showed an invasive growth pattern and higher progression than tumor with YTN16 alone (P = 0.045). Additionally, YTN16 and LmcMF co-inoculated tumors showed lower infiltration of CD8+ cells and higher infiltration of M2 macrophages than tumors with YTN16 alone (P < 0.05, P < 0.05). These results indicate that LmcMF plays as cancer-associated fibroblasts (CAFs) by crosstalk with YTN16 and CAFs contribute tumor progression, invasion, fibrosis, and immune suppression. CONCLUSIONS: This model is the first immunocompetent mouse model similar to TME of human clinical PM with fibrosis. By using this model, new treatment strategies for PM, such as anti-CAFs therapies, may be developed.

Comparison of prognostic impact of anatomic location of the pancreas on postoperative pancreatic fistula in laparoscopic and open gastrectomy.

BACKGROUND: Postoperative pancreatic fistula (POPF) is a serious complication after gastric cancer surgery. The current study aimed to investigate the significance of the anatomic location of the pancreas as a predictor for POPF in both laparoscopic gastrectomy (LG) and open gastrectomy (OG). METHODS: In total, 233 patients with gastric cancer were assessed retrospectively. We measured the maximum vertical (P-L height; PLH) and horizontal length (P-L depth; PLD) between the upper border of pancreas and the root of left gastric artery on a preoperative CT in the sagittal direction. The maximum length of the vertical line between the surface of the pancreas and the aorta (P-A length), previously reported as prognostic factor of POPF, was also measured. We investigated the correlations between these parameters and the incidence of POPF in LG and OG groups. RESULTS: Among the patients in this study, 118 underwent OG and 115 underwent LG. In LG, the median PLH and P-A length in patients with POPF were significantly longer compared with those without POPF (p = 0.026, 0.034, respectively), but not in OG. There was no significant difference in the median PLD between the patients with or without POPF in both LG and OG. The multivariate analysis demonstrated that PLH (odds ratio [OR] 4.19, 95% confidence interval [CI] 1.57-11.3, P = 0.004) and P-A length (OR 4.06, 95%CI 1.05-15.7, P = 0.042] were independent factors for predicting POPF in LG. However, intraoperative blood loss (OR 2.55, 95%CI 1.05-6.18, P = 0.038) was extracted as an independent factor in OG. The median amylase level in the drained fluid (D-Amy) were significantly higher in patients with high PLH(≥12.4 mm) or high P-A length (≥45 mm) compared with those with low PLH or low P-A length in LG. However, there were no differences in the D-Amy levels by PLH or P-A length in OG patients. CONCLUSIONS: The anatomic location of the pancreas is a specific and independent predictor of POPF in LG but not in OG. PLH is a simple parameter that can evaluate the anatomic position of the pancreas, and it may be useful for preventing POPF after LG.