Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Gastric Cancer with Synchronous Peritoneal Metastases: Multicenter Study of 'Italian Peritoneal Surface Malignancies Oncoteam-S.I.C.O.'

BACKGROUND: The development of multimodality treatment, including cytoreductive surgery (CRS) with heated intraperitoneal chemotherapy (HIPEC), has led to promising results in selected patients with peritoneal disease of gastric origin. The aim of this study was to investigate the short- and long-term outcomes of CRS/HIPEC in the treatment of synchronous peritoneal metastasis in gastric cancer. METHODS: The Italian Peritoneal Surface Malignancies Oncoteam-S.I.C.O. retrospective registry included patients with synchronous peritoneal malignancy from gastric cancer submitted to gastrectomy with CRS and HIPEC between 2005 and 2018 from 11 high-volume, specialized centers. RESULTS: A total of 91 patients with a median age of 58 years (range 26-75) were enrolled. The median overall survival (OS) time for the whole group of patients was 20.2 months (95% confidence interval [CI] 11.8-28.5] and the median recurrence-free survival (RFS) was 7.3 months (95% CI 4-10.6). The completeness of cytoreduction score (CCS) of 0 and Peritoneal Cancer Index (PCI) score of ≤ 6 groups showed a significantly better long-term survival (median OS 40.7 and 44.3 months, respectively) compared with the incomplete resected groups (median OS 10.7 months, p = 0.003) and PCI score of > 6 group (median OS 13.4 months, p = 0.005). A significant difference was observed in the survival rate according to neoadjuvant treatment (untreated patients: 10.7 months, 95% CI 5.1-16.2; treated patients: 35.3 months, 95% CI 2.8-67.8; p = 0.022). CONCLUSIONS: In referral centers, CRS and HIPEC after neoadjuvant treatment significantly improved survival in selected patients. Patients with a PCI score ≤ 6, complete cytoreduction, negative nodal involvements, and negative cytology had encouraging results, showing a clinically meaningful survival.

Looking for a strategy in treating peritoneal gastric cancer carcinomatosis: an Italian multicenter Gastric Cancer Research group's analysis.

BACKGROUND: The present study provides a snapshot of Italian patients with peritoneal metastasis from gastric cancer treated by surgery in Italian centers belonging to the Italian Research Group on Gastric Cancer. Prognostic factors affecting survival in such cohort of patients were evaluated with the final aim to identify patients who may benefit from radical intent surgery. METHODS: It is a multicentric retrospective study based on a prospectively collected database including demographics, clinical, surgical, pathological, and follow-up data of patients with gastric cancer and synchronous macroscopic peritoneal metastases. Patients were surgically treated from January 2005 to January 2017. We focused on patients with macroscopic peritoneal carcinomatosis (PC) treated with upfront surgery in order to provide homogeneous evidences. RESULTS: Our results show that patients with peritoneal carcinomatosis cannot be considered all lost. Strictly selected cases (R0/R1 and P1 patients) could benefit from an aggressive surgical approach performing an extended lymphadenectomy and HIPEC treatment. CONCLUSION: The main result of the study is that GC patients with limited peritoneal involvement can have a survival benefit from a surgery with "radical oncological intent", that means extended lymphadenectomy and R0 resection. The retrospective nature of this study is an important bias, and for this reason, we have started a prospective multicentric study including Italian stage IV patients that hopefully will give us more answers.

Conversion gastrectomy for stage IV unresectable gastric cancer: a GIRCG retrospective cohort study.

BACKGROUND: The aim of this study is to report the experience with conversion surgery from six Gruppo Italiano Ricerca Cancro Gastrico (GIRCG) centers, focusing our analysis on factors affecting survival and the risk of recurrence. METHODS: A retrospective, multicenter cohort study was performed in patients who had undergone conversion gastrectomy between 2005 and 2017. Data were extracted from a GIRCG database including all metastatic gastric cancer patients submitted to surgery. Only stage IV unresectable tumors/metastases which became resectable after chemotherapy were included in this analysis. RESULTS: Forty-five resected M1 patients were included in the analysis. Reasons for being deemed unresectable at diagnosis were peritoneal involvement (PCI > 6) (n = 38, 84.4%), distant metastatic nodes (n = 3, 6.6%) and extensive liver involvement (n = 4, 8.8%). Median follow-up was 25 months (IQR 9-50). Median overall survival from surgery was 15 months and 1-, 3- and 5-year survivals were 57.2, 36.1 and 24%, respectively. Median progression-free survival was 12 months with 1- and 3-year survival of 46.4 and 33.9%, respectively. At cox regression analysis the only independent prognostic factor for OS was the presence of more than one type of metastasis (HR 4.41, 95% CI 1.72-11.3, p = 0.002). A positive microscopic resection margin was the only risk factor for recurrence (HR 5.72, 95% CI 1.04-31.4, p = 0.045). CONCLUSIONS: Unresectable stage IV GC patients could benefit from radical surgery after chemotherapy and achieve long survivals. The main prognostic factor for these patients was the presence of more than one type of extra-gastric metastatic involvement.

Prognostic value of the seventh AJCC/UICC TNM classification of non-cardia gastric cancer.

BACKGROUND: The TNM staging criteria for gastric carcinoma have seen numerous revisions, the most recent of which are reflected in the seventh edition AJCC TNM cancer staging manual. METHODS: A retrospective evaluation of the sixth and seventh TNM classification of gastric cancer on a prospective database, regarding patients operated on for primary gastric cancer, was conducted. The end point of the study was prognosis evaluation in terms of overall survival.Patients operated on for primary gastric cancer between September 2003 and March 2012 at our Department of Emergency and General Surgery, were consecutively retrieved in this study; a total of 114 patients were considered. Cardia gastric cancers, gastric lymphomas and gastrointestinal stromal tumors (GIST) were excluded. Median and mean follow-up periods were 22.5 and 27.7 months (range 15 days to 5 years). Both TNM6 and TNM7 were used to evaluate our patients. Overall survival and survival rates at different stages were analyzed using the Kaplan-Meier method and differences were determined using a log-rank test. Cox's proportional hazard model was used to identify significant factors related to prognosis in a multivariate analysis. RESULTS: Overall survival between the sixth and seventh TNM classification was not significantly different. Both the Kaplan-Meier analysis and the multivariate analysis showed that the major negative prognostic factor was lymphovascular invasion (P<0.001 in the univariate analysis and P=0.035 to 0.048 in the multivariate analysis). Stage distribution and stage-related survival changed from the sixth to the seventh edition, especially in T3 stage where median survival for the sixth edition was 720 days versus 1,200 days for the seventh edition. Moreover, differences were shown in the survival rate of N1 versus N2 stages within the seventh TNM. CONCLUSIONS: Even though further studies are needed in order to increase the number of patients studied, the seventh edition seems to provide a more accurate prognosis, especially regarding N1 and N2 tumors, showing that the most important prognostic factor is lymphovascular invasion.

Evaluation of peritoneal Carcinoembryonic Antigen as a survival prognostic factor in gastric cancer patients: a single western center experience.

The aim of this study is to define the importance of peritoneal CEA (pCEA) as a prognostic factor of overall survival (OS) and disease-free survival (DFS) in gastric cancer (GC) patients surgically treated with a curative intent In our department. A total of 64 patients affected by gastric cancer with intraoperatively measurement of CEA on peritoneal lavage were enrolled in the study. Patients were divided into two groups: (A) the peritoneal lavage CEA ( -) with CEA < 0.5 ng/ml and (B) the peritoneal lavage CEA ( +) with CEA ≥ 0.5 ng/ml. Then we analyzed OS and DFS of the two groups correlating them to others clinico-pathological features. Furthermore, we investigated the correlation between pCEA and peritoneal cytology. We demonstrated a strong significant difference in OS and in DFS in CEA ( +) patients. We emphasized that pCEA had a strong survival impact, in both OS and DFS, in selected patients affected by diffuse histotype GC (p = 0.0048 and p = 0.0030 respectively), stage III (p = 0.015 and p = 0.021, respectively) and distal gastric cancer (p = 0.0036 and p = 0.0017, respectively). There is a strong need to recognize prognostic factors that can help clinicians to stratify patients at high risk to develop post-surgical recurrences and moreover to recognize who could benefit from an aggressive surgical treatment of cytoreductive surgery and intra-peritoneal chemotherapy.pCEA is a good predictor of survival in advanced gastric cancer and could discriminate which patients need a more accurate follow-up program and an intensive therapeutic strategy.

Prognostic Survival Significance of Signet Ring Cell (SRC) Gastric Cancer: Retrospective Analysis from a Single Western Center.

INTRODUCTION: Signet ring cell carcinoma accounts for 35% to 45% of all gastric cancer. Despite the acknowledgment of its more aggressive pathological features, various controversies surrounding this topic still exist. Thus, we investigate the clinical pathological characteristics and survival prognostic significance of signet ring cell components in patients affected by gastric cancer. METHODS: From January 2004 to December 2020, in a retrospective study, we enrolled 404 patients with gastric cancer who were curatively treated in our department. The male-to-female ratio was 249/142, and the median age was 75 (range 37-94). We dichotomized patients into two groups (75 patients vs. 316 patients) based on the signet ring cell presence; according to preoperative, operative, and postoperative characteristics, we performed a univariate and multivariate analysis for overall survival. RESULTS: Signet ring cell carcinoma indicated an increasing incidence trend over the time analyzed. Overall median survival of signet ring cell and non-signet ring cell carcinoma were, respectively, 16 vs. 35 months, p < 0.05. In early gastric cancer, the prognosis of the signet ring cell is better than that of the non-signet ring cell, as opposed to advanced cancer. Among the entire population in the multivariate analysis, the only independent factors were preoperative serum albumin level, complete surgical resection, level of lymphadenectomy, and pathological stage. Recurrence occurred more frequently in patients affected by signet ring cell, but in our data, we could not identify a peculiar site of recurrence. CONCLUSIONS: Signet ring cell carcinoma has a specific oncogenetic phenotype and treatment resistance heterogeneity; however, it is not always associated with poor prognosis. According to our results, a radical surgical procedure associated with an adequate lymphadenectomy should be advocated to improve patients survival. Gastric cancer patients with signet ring cell components should draw clinicians' attention.

Consequences of the COVID-19 pandemic on the diagnosis and treatment of gastric cancer in referral centers in Italy.

BACKGROUND: The coronavirus pandemic had a major impact in Italy. The Italian health system's re-organization to face the emergency may have led to significant consequences especially in the diagnosis and treatment of malignancies. This study aimed to assess the impact of the pandemic in the diagnosis and treatment of gastric cancer in nine Gruppo Italiano RIcerca Cancro Gastrico (GIRCG) centers. METHODS: All patients assessed for gastric adenocarcinoma at nine GIRCG centers between January 2019 and November 2020 were included. Patients were grouped according to the date of "patient 1's" diagnosis in Italy: preCOVID versus COVID. Clinico-pathological and outcome differences between the two groups were analyzed. RESULTS: A total of 632 patients were included in the analysis (205 in the COVID group). The cT4 weighted ratios were higher in 2020 from April to September, with the greatest differences in May, August and September. The cM+ weighted ratio was significantly higher in July 2020. The mean number of gastrectomies had the greatest reduction in March and May 2020 compared with 2019. The median times from diagnosis to chemotherapy, to complete diagnostic work-up or to operation were longer in 2019. The median time from the end of chemotherapy to surgery was 17 days longer in the preCOVID group. CONCLUSIONS: A greater number of advanced or metastatic cases were diagnosed after the spread of SARS-CoV-2 infection, especially after the "full lockdown" periods. During the pandemic, once gastric cancer patients were referred to one of the centers, a shorter time to complete the diagnostic work-up or to address them to the best treatment option was required.

Which gastric cancer patients could benefit from staging laparoscopy? A GIRCG multicenter cohort study.

BACKGROUND: This study aimed to investigate which gastric cancer patients could benefit the most from staging laparoscopy. METHODS: A retrospective cohort study was carried out, including 316 (216 cM- and 100 cM+) gastric cancer patients who had undergone staging laparoscopy between 2010 and 2020 in seven GIRCG centers. A model including easily-accessible clinical, biochemical and pathological markers was constructed to predict the risk of carcinomatosis. ROC curve and decision curve analyses were used to verify its accuracy and net benefit. RESULTS: In the cM-population staging laparoscopy could detect 67 cases who had peritoneal carcinomatosis or positive cytology, for a yield of 30.5%. In cM-patients, intestinal type tumors (0.25, 0.12-0.51; p = 0.002), cT4 tumors (2.18, 1.11-4.28; p = 0.023) and cancers of the lower third (0.31, 0.14-0.70; p = 0.004) were associated with the presence of peritoneal carcinomatosis and/or positive cytology. The ROC curve analysis of the model including the three variables showed an AUC of 0.75 (0.68-0.81, p < 0.001). The decision curve analyses showed that the model had a higher net benefit than the treating all strategy between threshold probabilities of 15 and 50%. CONCLUSIONS: Staging laparoscopy is a useful tool to address the patient with gastric cancer to the most adequate treatment. In cM-patients the assessment of the location of the tumor, the Lauren's histotype and the cT status may help in providing additional elements in indicating or not the use of staging laparoscopy.

Next-Generation Sequencing Analysis of Gastric Cancer Identifies the Leukemia Inhibitory Factor Receptor as a Driving Factor in Gastric Cancer Progression and as a Predictor of Poor Prognosis.

Gastric cancer (GC) is the third cause of cancer-related mortality worldwide. Nevertheless, because GC screening programs are not cost-effective, most patients receive diagnosis in the advanced stages, when surgical options are limited. Peritoneal dissemination occurs in approximately one-third of patients with GC at the diagnosis and is a strong predictor of poor outcome. Despite the clinical relevance, biological and molecular mechanisms underlying the development of peritoneal metastasis in GC remain poorly defined. Here, we report results of a high-throughput sequencing of transcriptome expression in paired samples of non-neoplastic and neoplastic gastric samples from 31 patients with GC with or without peritoneal carcinomatosis. The RNA-seq analysis led to the discovery of a group of highly upregulated or downregulated genes, including the leukemia inhibitory factor receptor (LIFR) and one cut domain family member 2 (ONECUT2) that were differentially modulated in patients with peritoneal disease in comparison with patients without peritoneal involvement. Both LIFR and ONECUT2 predicted survival at univariate statistical analysis. LIFR and its major ligand LIF belong to the interleukin-6 (IL-6) cytokine family and have a central role in immune system regulation, carcinogenesis, and dissemination in several human cancers. To confirm the mechanistic role of the LIF/LIFR pathway in promoting GC progression, GC cell lines were challenged in vitro with LIF and a LIFR inhibitor. Among several GC cell lines, MKN45 cells displayed the higher expression of the receptor, and their exposure to LIF promotes a concentration-dependent proliferation and epithelial-mesenchymal transition (EMT), as shown by modulation of relative expression of E-cadherin/vimentin along with JAK and STAT3 phosphorylation and acquisition of a migratory phenotype. Furthermore, exposure to LIF promoted the adhesion of MKN45 cells to the peritoneum in an ex vivo assay. These effects were reversed by the pharmacological blockade of LIFR signaling. Together, these data suggest that LIFR might have a major role in promoting disease progression and peritoneal dissemination in patients with GC and that development of LIF/LIFR inhibitors might have a role in the treatment of GC.

Neoadjuvant Chemotherapy for Locally Advanced Gastric Cancer: Where we Stand; An Italian Single Center Perspective.

BACKGROUND/AIM: Neoadjuvant or perioperative chemotherapy is the standard treatment for locally advanced gastric cancer. However, in Eastern countries this is still debated. The aim of our study was to evaluate the survival impact of neoadjuvant chemotherapy. PATIENTS AND METHODS: A total of 60 patients who underwent preoperative chemotherapy were compared to patients with locally advanced gastric cancer that underwent upfront surgery. RESULTS: Median survival of the entire group curatively treated was 41 months with a median progression-free survival of 38 months. By excluding patients with stage IV disease from the neoadjuvant group, a statistically significant difference was reached both in terms of overall survival and disease-free survival. By subdividing patients according to pTNM stages, neoadjuvant patients showed better survival in stage I and II. CONCLUSION: Neoadjuvant chemotherapy could be an effective treatment for locally advanced disease. However, randomized studies are still needed to fully understand its role and identify patients that will benefit from it.

Analysis of Gastric Cancer Transcriptome Allows the Identification of Histotype Specific Molecular Signatures With Prognostic Potential.

Gastric cancer is the fifth most common malignancy but the third leading cause of cancer-associated mortality worldwide. Therapy for gastric cancer remain largely suboptimal making the identification of novel therapeutic targets an urgent medical need. In the present study we have carried out a high-throughput sequencing of transcriptome expression in patients with gastric cancers. Twenty-four patients, among a series of 53, who underwent an attempt of curative surgery for gastric cancers in a single center, were enrolled. Patients were sub-grouped according to their histopathology into diffuse and intestinal types, and the transcriptome of the two subgroups assessed by RNAseq analysis and compared to the normal gastric mucosa. The results of this investigation demonstrated that the two histopathology phenotypes express two different patterns of gene expression. A total of 2,064 transcripts were differentially expressed between neoplastic and non-neoplastic tissues: 772 were specific for the intestinal type and 407 for the diffuse type. Only 885 transcripts were simultaneously differentially expressed by both tumors. The per pathway analysis demonstrated an enrichment of extracellular matrix and immune dysfunction in the intestinal type including CXCR2, CXCR1, FPR2, CARD14, EFNA2, AQ9, TRIP13, KLK11 and GHRL. At the univariate analysis reduced levels AQP9 was found to be a negative predictor of 4 years survival. In the diffuse type low levels CXCR2 and high levels of CARD14 mRNA were negative predictors of 4 years survival. In summary, we have identified a group of genes differentially regulated in the intestinal and diffuse histotypes of gastric cancers with AQP9, CARD14 and CXCR2 impacting on patients' prognosis, although CXCR2 is the only factor independently impacting overall survival.

Limited Usefulness of 18F-FDG PET/CT in Predicting Tumor Regression After Preoperative Chemotherapy for Noncardia Gastric Cancer: The Italian Research Group for Gastric Cancer (GIRCG) Experience.

BACKGROUND: The present study aimed to better define the usefulness of F-FDG PET/CT in predicting pathological tumor response (PTR) and survival in patients with noncardia gastric cancer treated with preoperative chemotherapy. METHODS: Seventy-one patients were recruited in 6 Italian centers. The SUV of F-FDG PET/CT was measured at baseline and after treatment, and the difference (dSUV) was computed. The association between PET indexes and PTR, assessed by the Becker score, was evaluated by nonparametric regression. The discriminant power of PET indexes with respect to the absence of PTR (Becker 2/3) was studied by receiver operating characteristic (ROC) curve and synthesized by the area under the curve (ROC-AUC). RESULTS: dSUV allowed to partially discriminate between absence/presence of PTR, when expressed as either absolute value (ROC-AUC, 0.73; 95% confidence interval, 0.59-0.87) or percentage (ROC-AUC, 0.74; 95% confidence interval, 0.59-0.89). However, only extreme values of percent dSUV were really informative. All 7 patients whose F-FDG uptake had increased despite preoperative treatment showed no tumor regression at pathologic examination. Seven of the 10 patients whose metabolic response had been 70% or greater had complete or nearly complete pathologic tumor regression (Becker score 1a or 1b). The metabolic response of the remaining 54 patients, which ranged between 0% and 70%, did not permit to reliably forecast pathologic tumor regression. Survival significantly decreased with increasing Becker score but was unaffected by metabolic response. CONCLUSIONS: The present study suggests that F-FDG PET/CT has limited usefulness in predicting cancer regression. The lack of metabolic response in serial measurements indicates the probable ineffectiveness of preoperative treatment.

Stage IV Gastric Cancer: The Surgical Perspective of the Italian Research Group on Gastric Cancer.

Background/Aim: This work explored the prognostic role of curative versus non-curative surgery, the prognostic value of the various localizations of metastatic disease, and the possibility of identifying patients to be submitted to aggressive therapies. Patients and Methods: Retrospective chart review of stage IV patients operated on in our institutions. Results: Two hundred and eighty-two patients were considered; 73.4% had a single metastatic presentation. In 117 cases, a curative (R0) resection of primary and metastases was possible; 75 received a R1 resection and 90 a palliative R2 gastrectomy. Surgery was integrated with chemotherapy in multiple forms: conversion therapy, HIPEC, neo-adjuvant and adjuvant treatment. Median overall survival (OS) of the entire cohort was 10.9 months, with 14 months for the R0 subgroup. There was no correlation between metastasis site and survival. At multivariate analysis, several variables associated with the lymphatic sphere showed prognostic value, as well as tumor histology and the curativity of the surgical procedure, with a worse prognosis associated with a low number of resected nodes, D1 lymphectomy, pN3, non-intestinal histology, and R+ surgery. Considering the subgroup of R0 patients, the variables pT, pN and D displayed an independent prognostic role with a cumulative effect, showing that patients with no more than 1 risk factor can reach a median survival of 33 months. Conclusions: Our data show that the possibility of effective care also exists for Western patients with stage IV gastric cancer.

Surgical treatment of hepatic metastases from gastric cancer.

The purpose of the study was to investigate the clinical factors influencing the prognosis of patients submitted to hepatectomy for metastases from gastric cancer and their clinical role. We conducted a retrospective multicentre review. We evaluated how survival from surgery was influenced by patient-related, tumour-related and treatment-related prognostic factors. We analysed data on 144 patients submitted to hepatectomy for metastases from gastric cancer, in the synchronous and metachronous setting. In 117 cases, an R0 resection was achieved, while in 27 an R + hepatic resection was performed. Chemotherapy was administered to 55 patients. Surgical mortality was 2.1% and morbidity 21.5%. One-, 3-, and 5-year OS rates after surgery were 49.9, 19.4 and 11.6%, respectively, with a median OS of 12.0 months. T4 gastric cancer, H3 hepatic involvement, non-curative resection, recurrence after surgery, and abstention from chemotherapy were associated with a worse prognosis. Factor T and H displayed a clear (p < 0.001) cumulative effect. Our data show that R0 resection must be pursued whenever possible. The treatment of T4 gastric cancer with hepatic bilateral and diffuse metastasis (H3) should be considered carefully or it should be probably avoided. Finally, a multimodal treatment associating surgery and chemotherapy offers the best survival results.

An aggressive early gastric cancer: Kodama's PenA type.

BACKGROUND: To investigate the role of Kodama PenA subtype in influencing survival in patients with early gastric cancer (EGC). METHODS: All patients surgically treated for EGC at 7 Italian centers (Forlì, Varese, Siena, Verona, Milan, Rome and Perugia) belonging to the Italian Research Group for Gastric Cancer (GIRCG) from January 1982 and December 2009 were included. RESULTS: PenA patients were 230 (21.5%) while other types were 839 (78.5%). Nodal metastases were more common in PenA (30.7%) than non-PenA (10.4%) EGCs. Among preoperative variables, only age (OR 1.02; 95% CI 1.00-1.03, p = 0.009) and macrotype III (OR 1.95; 95% CI 1.39-2.75, p = 0.0001) were significantly associated with Pen A type. Survival analysis performed on N0 patients demonstrated that only size >2 cm (HR 1.85; 95% CI 1.12-3.05, p = 0.017) and age (HR 1.06; 95% CI 1.03-1.08, p < 0.0001) were independent poor prognostic factor. Among N+ patients age (HR 1.04; 95% CI 1.00-1.07, p = 0.048), number of positive lymph nodes (HR 1.13; 95% CI 1.05-1.20, p = 0.0002) and PenA (HR 4.23; 95% CI 1.70-10.55, p = 0.002) were significantly correlated with poor prognosis at multivariate analysis. CONCLUSIONS: Kodama PenA subtype was the most powerful independent prognostic factor in patients with nodal metastases. Its status should always be investigated in EGCs patients.

Hyperthermic intraperitoneal chemotherapy as palliative treatment for malignant ascites A single-center experience and a review of the literature.

Malignant ascites is an abnormal accumulation of fluid in the peritoneal cavity of patients with intraperitoneal cancer dissemination. This clinical condition could represent the terminal evolution of a lethal disease and could influence the prognosis, severely impairing the patients' quality of life. Treatment options include a multitude of different procedures with limited efficacy and some degree of risk; diuretics, paracentesis, peritoneo-venous shunts and intraperitoneal biologic agents like anti-VEGF molecules, metalloproteinase inhibitors and immunomodulators are included. None of these approaches have been established as a standard of care because of their low efficacy or severe side effects. The last two decades saw the emergence of cytoreductive surgery with hyperthermic intraperitoneal perioperative chemotherapy (HIPEC) as a viable therapeutic approach resulting in an effective cure against refractory malignant ascites. The following describes our experiences with 3 cases together with a literature review. KEY WORDS: Chemotherapy, HIPEC, Laparoscopy, Malignant ascites.

The bile acid receptor GPBAR1 (TGR5) is expressed in human gastric cancers and promotes epithelial-mesenchymal transition in gastric cancer cell lines.

GPBAR1 (also known as TGR5) is a bile acid activated receptor expressed in several adenocarcinomas and its activation by secondary bile acids increases intestinal cell proliferation. Here, we have examined the expression of GPBAR1 in human gastric adenocarcinomas and investigated whether its activation promotes the acquisition of a pro-metastatic phenotype. By immunohistochemistry and RT-PCR analysis we found that expression of GPBAR1 associates with advanced gastric cancers (Stage III-IV). GPBAR1 expression in tumors correlates with the expression of N-cadherin, a markers of epithelial-mesenchymal transition (EMT) (r=0.52; P<0.01). Expression of GPBAR1, mRNA and protein, was detected in cancer cell lines, with MKN 45 having the higher expression. Exposure of MKN45 cells to GPBAR1 ligands, TLCA, oleanolic acid or 6-ECDCA (a dual FXR and GPBAR1 ligand) increased the expression of genes associated with EMT including KDKN2A, HRAS, IGB3, MMP10 and MMP13 and downregulated the expression of CD44 and FAT1 (P<0.01 versus control cells). GPBAR1 activation in MKN45 cells associated with EGF-R and ERK1 phosphorylation. These effects were inhibited by DFN406, a GPBAR1 antagonist, and cetuximab. GPBAR1 ligands increase MKN45 migration, adhesion to peritoneum and wound healing. Pretreating MKN45 cells with TLCA increased propensity toward peritoneal dissemination in vivo. These effects were abrogated by cetuximab. In summary, we report that GPBAR1 is expressed in advanced gastric cancers and its expression correlates with markers of EMT. GPBAR1 activation in MKN45 cells promotes EMT. These data suggest that GPBAR1 antagonist might have utility in the treatment of gastric cancers.