Issues on peritoneal metastasis of gastric cancer: an update

Single centre experience with conversion surgery for advanced and metastatic gastric cancer in Slovakia

Conversion surgery (CS) following systemic chemotherapy (SCT) has been suggested as a promising strategy for improving prognosis of patients with advanced gastric carcinoma (GC). The evidence, however, comes mostly from small-scale studies. Moreover, controversy exists over the criteria for selecting patients for SCT. We retrospectively analyzed 123 patients treated between 2007 and 2023. Thirty-one underwent CS, 44 received primary radical surgery (R0) with adjuvant chemotherapy (ACT), and 48 received surgical or palliative treatment. Survival rates and predictors of successful conversion were assessed. Median survival for R0 + ACT (30.4 months, 95%CI: 20.9-45.0) was non-significantly higher than SCT + R0 (19.4 months, 95%CI: 10.3-40.1; P = 0.2353). Successful downstaging after SCT was observed in 54.8% of CS patients. This group of SCT responders had significantly lower laboratory markers CEA, NLR and PLR (P-value of 0.019; 0.036 and 0.029, respectively). Both successful and failed conversion groups had significantly longer survival than group with palliative treatment (16.0 months, 95%CI: 8.4-19.1 vs. 7.4 months, 95%CI: 5.3-9.9; P = 0.0003). Multivariable analysis confirmed significantly lowered hazard and prolonged overall survival in CS vs. palliative treatments after adjusting for age and stage differences (P = 0.0014). Conversion therapy improves short-term survival and offers potential for long-term survival in select stage IV GC patients.

Efficacy analysis of prophylactic hyperthermic intraperitoneal chemotherapy in patients with locally advanced gastric cancer: a retrospective study

Purpose

This study aims to evaluate the effectiveness and safety of prophylactic hyperthermic intraperitoneal chemotherapy (P-HIPEC) in patients with locally advanced gastric cancer (AGC) after laparoscopic radical gastrectomy. Additionally, it explores how the frequency and timing of P-HIPEC influence treatment outcomes.

Methods

A retrospective analysis was conducted on 227 patients with locally AGC who underwent laparoscopic surgery at Maoming People's Hospital from January 2016 to December 2022. Patients were stratified into the HIPEC group (n=101) and the non-HIPEC group (n=126), based on whether they received postoperative P-HIPEC. Propensity score matching (PSM) was used to adjust for baseline characteristics, facilitating a comparative analysis of survival outcomes, postoperative complications and recurrence patterns. Cox regression analysis was performed to identify prognostic factors. Furthermore, the impact of varying P-HIPEC frequencies and initiation timings was evaluated.

Results

No significant differences in overall survival (OS) or postoperative complication rates were observed between the two groups in the original and PSM cohorts. But the disease-free survival (DFS) of the HIPEC group was significantly higher than that of the non-HIPEC group (HR 0.569; 95% CI 0.362-0.894; p = 0.013) in the PSM cohort, with 1-year, 3-year, and 5-year DFS rates showing notable improvement (77.9% vs. 69.7%, 60.1% vs. 43.0%, and 46.2% vs. 25.5%). The incidence of isolated peritoneal metastasis (PM) was significantly lower in the HIPEC group (5.3% vs. 17.3%, p = 0.039). Multivariate Cox regression analysis identified P-HIPEC as an independent protective factor for DFS. Further analysis indicated that neither the number of P-HIPEC sessions had a significant impact on OS (p = 0.388) or DFS (p = 0.735), nor did the timing of P-HIPEC initiation affect OS (p = 0.620) or DFS (p = 0.488). Likewise, different P-HIPEC frequencies or initiation timings had no significant impact on postoperative complication rates or recurrence patterns.

Conclusion

P-HIPEC effectively reduces the risk of postoperative PM and improves DFS in patients with locally AGC without increasing postoperative complications. However, it does not significantly impact OS. Additionally, variations in the frequency and timing of P-HIPEC initiation do not significantly affect survival outcomes, postoperative complications, or recurrence patterns.

Optimal hyperthermic intraperitoneal chemotherapy regimen for advanced and peritoneal metastatic gastric cancer: a systematic review and Bayesian network meta-analysis

Background

Peritoneal metastasis is one of the most common modes of spread of gastric cancer. Currently, surgical treatment combined with hyperthermic intraperitoneal chemotherapy (HIPEC) and systemic chemotherapy has demonstrated promising outcomes in both the treatment and prevention of peritoneal metastasis in gastric cancer. However, various HIPEC drug regimens are in clinical use, and their efficacy remains unclear. This study aims to evaluate the effectiveness of different HIPEC drug regimens in patients with advanced gastric cancer to determine the optimal therapeutic approach.

Methods

This study conducted a systematic review and Bayesian network meta-analysis. Patients in the experimental group underwent surgery combined with HIPEC and chemotherapy. The search period covered literature from database inception to June 1, 2024. Hazard ratios (HRs) with 95% confidence intervals (CIs) were used to evaluate overall survival (OS) as the primary outcome. Odds ratios (ORs) with 95% CIs were used to assess overall disease recurrence, peritoneal recurrence, and postoperative morbidity as secondary outcomes. To ensure scientific rigor and transparency, this study has been registered with PROSPERO (CRD42024533948).

Results

A total of 11 randomized controlled trials (RCTs) involving 1092 patients were included. Compared to surgery combined with chemotherapy, the regimens of cisplatin (HRs = 0.52, 95% CI: 0.38-0.73), mitomycin C (HRs = 0.99, 95% CI: 0.55-1.79), cisplatin plus fluorouracil (HRs = 0.60, 95% CI: 0.38-0.95), and oxaliplatin plus 5-fluorouracil (HRs = 0.53, 95% CI: 0.36-0.78) all demonstrated benefits in OS. The cisplatin (ORs = 0.16, 95% CI: 0.03-0.60) and mitomycin C (ORs = 0.03, 95% CI: 0-0.71) regimens also showed advantages in reducing peritoneal recurrence, with no impact on postoperative morbidity. Importantly, the cisplatin regimen was superior to other regimens in terms of OS and overall disease recurrence, achieving a balance between efficacy and safety.

Conclusions

Compared to chemotherapy alone, HIPEC treatment shows significant benefits in OS without a notable disadvantage in postoperative morbidity. Although no single HIPEC regimen demonstrated clear benefits across all outcomes, the cisplatin regimen performed well in multiple aspects, indicating its potential for further research and clinical application.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=533948, identifier CRD42024533948.

Dual-energy CT quantitative parameters to evaluate occult peritoneal metastasis in advanced gastric cancer preoperatively

PURPOSE

To explore whether dual-energy CT (DECT) quantitative parameters could provide analytic value for the diagnosis of patients with occult peritoneal metastasis (OPM) in advanced gastric cancer preoperatively.

MATERIALS AND METHODS

This retrospective study included 219 patients with advanced gastric cancer and DECT scans. The patient's clinical data and DECT related iodine concentration (IC) parameters and effective atomic number (Zeff) were collated and analyzed among noun-peritoneal metastasis (NPM), OPM and radiologically peritoneal metastasis (RPM) groups. The predictive performance of the DECT parameters was compared with that of the conventional CT features and clinical characteristics through evaluating area under curve of the precision-recall (AUC-PR), F1 score, balanced accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).

RESULTS

Borrmann IV type diagnosed on CT and serum tumor indicator CA125 index were statistically different between the NPM and OPM groups. DECT parameters included IC, normalized IC (NIC), and Zeff of PM group were lower than the NPM group. The DECT predictive nomogram combined three independent DECT parameters produced a better diagnostic performance than the conventional CT feature Borrmann IV type and serum CA125 index in AUC-PR with 0.884 vs 0.368 vs 0.189, but similar to the combined indicator which was based on the DECT parameters, the conventional CT feature, and serum CA125 index in AUC-PR with 0.884 vs 0.918.

CONCLUSION

The lower quantitative NIC, IC ratio, and Zeff on DECT was associated with peritoneal metastasis in advanced gastric cancer and was promising to identify patients with OPM noninvasively.

GRP94 promotes anoikis resistance and peritoneal metastasis through YAP/TEAD1 pathway in gastric cancer

Anoikis resistance allows cancer cells to avoid death caused by detachment from the extracellular matrix's adhesion, enabling these cells to infiltrate and migrate to regions such as the peritoneum. This study emphasizes GRP94's involvement in anoikis resistance and peritoneal metastasis in gastric cancer (GC). It's found that GRP94 overexpression, linked to poor prognosis, was potentially due to SP1 and GRP94 promoter interactions, confirmed through dual luciferase reporter (DLR), chromatin immunoprecipitation (ChIP), and quantitative real-time PCR (real-time qPCR). Increased GRP94 enhanced GC cells' anoikis resistance and metastasis. Decreasing GRP94 had opposite effects, potentially through yes-associated protein (YAP)/TEAD1 axis inhibition, with raised YAP phosphorylation and decreased TEAD1 levels detected by western blotting (WB). Inhibiting YAP counteracted GRP94's effects on anoikis resistance and metastasis, while activating YAP reversed the effects of GRP94 reduction. Animal experiments verified GRP94's contribution to GC's peritoneal metastasis. In conclusion, our work highlights the effect of GRP94 on anoikis resistance, showing potential value in treating peritoneal metastasis of GC.

Predicting gastric cancer response to anti-HER2 therapy or anti-HER2 combined immunotherapy based on multi-modal data

The sole use of single modality data often fails to capture the complex heterogeneity among patients, including the variability in resistance to anti-HER2 therapy and outcomes of combined treatment regimens, for the treatment of HER2-positive gastric cancer (GC). This modality deficit has not been fully considered in many studies. Furthermore, the application of artificial intelligence in predicting the treatment response, particularly in complex diseases such as GC, is still in its infancy. Therefore, this study aimed to use a comprehensive analytic approach to accurately predict treatment responses to anti-HER2 therapy or anti-HER2 combined immunotherapy in patients with HER2-positive GC. We collected multi-modal data, comprising radiology, pathology, and clinical information from a cohort of 429 patients: 310 treated with anti-HER2 therapy and 119 treated with a combination of anti-HER2 and anti-PD-1/PD-L1 inhibitors immunotherapy. We introduced a deep learning model, called the Multi-Modal model (MuMo), that integrates these data to make precise treatment response predictions. MuMo achieved an area under the curve score of 0.821 for anti-HER2 therapy and 0.914 for combined immunotherapy. Moreover, patients classified as low-risk by MuMo exhibited significantly prolonged progression-free survival and overall survival (log-rank test, P < 0.05). These findings not only highlight the significance of multi-modal data analysis in enhancing treatment evaluation and personalized medicine for HER2-positive gastric cancer, but also the potential and clinical value of our model.

Novel nomogram and risk stratification for peritoneal recurrence after curative resection in gastric cancer

Peritoneal recurrence (PR) in gastric cancer after curative resection has poor prognosis. Therefore, we aimed to construct a nomogram to predict PR, and establish PR score for risk stratification to guide adjuvant chemotherapy. A total of 315 patients with gastric cancer after radical surgery were included, and randomly stratified into training group (n = 221) and validation group (n = 94). Univariate and multivariate analyses were used to determine predictive factors of PR. The nomogram was constructed to predict the risk of PR. We utilized the time-dependent area under the receiver operating characteristic (ROC) curves (AUCs), calibration curves, and decision curve analysis (DCA) to evaluate the performance of the nomogram. Multivariate analysis showed that tumor site, N stage, preoperative CEA, and postoperative CA199 were independent predictors of PR. A nomogram was constructed to predict PR based on these factors. The AUC value was 0.755 in the training group and 0.715 in the validation group. The calibration curves showed good agreement between prediction and observation in the training and validation groups. The decision curve analysis displayed a good net benefit of the nomogram. The novel PR score was developed and patients were stratified into the low-, medium-, and high -risk groups. For the high-risk group, postoperative adjuvant chemotherapy significantly improved patients' overall survival (OS) and disease-free survival (DFS). The establishment of nomogram facilitates the prediction of PR after radical gastrectomy, and a novel PR score may help guide adjuvant chemotherapy for gastric cancer.

Short-Term Safety Evaluation of Albumin-Bound Paclitaxel in Intraoperative and Postoperative Hyperthermic Intraperitoneal Chemotherapy for Gastric Cancer

PURPOSE

To evaluate the short-term safety of albumin-bound paclitaxel in hyperthermic intraperitoneal chemotherapy (HIPEC) during and after gastric cancer (GC) surgery.

METHODS

A retrospective analysis of clinical data was conducted for GC surgery patients at Zhongnan Hospital of Wuhan University, from January 2020 to September 2022. The study group (n = 120) received HIPEC and the control group (n = 268) did not receive albumin-bound paclitaxel. Short-term safety indicators including intraoperative complications, hematological toxicity, liver and kidney function, and gastrointestinal function recovery were compared between the two groups.

RESULTS

There were no statistically significant differences between the two groups regarding intraoperative complications, hematological toxicity, liver and kidney function, and gastrointestinal function recovery time (P > 0.05 for all). In the study group, patients were further divided into subgroups based on dose and timing. Subgroup analysis revealed no significant differences among the different dose subgroups. However, when focusing on timing subgroups, the postoperative subgroup exhibited significantly higher white blood cell counts and bilirubin levels compared to the intraoperative subgroup, while the intraoperative subgroup had significantly higher bilirubin levels compared to both postoperative and intraoperative plus postoperative subgroups.

CONCLUSION

Albumin-bound paclitaxel demonstrates good safety and tolerability in HIPEC during and after GC surgery, without increasing the risk of intraoperative complications.

The mechanism of polyphyllin in the treatment of gastric cancer was verified based on network pharmacology and experimental validation

Background

Polyphyllin is a class of saponins extracted from Paris polyphylla rhizomes and has been used in clinical application in China for more than 2000 years. However, the mechanism for treating gastric cancer (GC) is still unclear. This study was designed to predict the targets and mechanisms of total Polyphyllin from Paris polyphylla rhizomes for the treatment of GC.

Method

Firstly, PubChem and Swiss Target Prediction databases were utilized to collect the 12 ingredients of total Polyphyllin from Paris polyphylla rhizomes and their targets. GC-related genes were obtained from the GEO database. Then the intersecting targets to all these molecules that identified using Venny. Secondly, the intersecting targets were imported into STRING platform for protein-protein interaction (PPI) network. Moreover, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted in DAVID website. In addition, the GEPIA was applied to perform the expression levels, transcript levels, staging, and overall survival of hub genes. In addition, we used AutoDock Vina to evaluate binding affinity of molecular docking between key ingredients and anti-GC targets. In vitro cell experiments, we detected the cell viability of gastric cancer cells at 24, 36, and 48 h using CCK-8 assay. The G0/G1 of cell cycle and apoptosis were detected by flow cytometry. Finally, quantitative real time polymerase chain reaction (qRT-PCR) was used to detect the level of hub genes, and Western blot was used to detect the changes of PI3K/Akt signal pathway.

Results

Firstly, we identified 12 ingredients and 286 targets of total Polyphyllin. A total of 2653 GC-related differentially expressed genes (DEGs) were collected, including 1366 up-regulated genes and 1287 down-regulated genes. Moreover, 45 targets were obtained after intersection. Secondly, results of the GO enrichment suggested that these genes were closely related to cell proliferation, migration and aging. KEGG analysis suggested that Polyphyllin in GC therapy were mostly regulated by multiple pathways, including the pathways in cancer, calcium signaling pathway, Rap1 signaling pathway, phospholipase D signaling pathway, etc. In addition, GEPIA results exhibited that PDGFRB, KIT, FGF1, GLI1, F2R, and HIF1A were associated with GC progression, stage, and survival. Besides, the molecular docking results further confirmed that the binding energy of Polyphyllin Ⅲ with HIF1A was minimal. In vitro cell experiments, Polyphyllin Ⅲ inhibited the cell viability of gastric cancer cells, blocked the cell cycle G0/G1 phase, and induced cell apoptosis. In addition, Polyphyllin Ⅲ down-regulated the mRNA levels of PDGFRB, KIT, FGF1, GLI1, F2R, and HIF1A, and regulated the PI3K/Akt signal pathway.

Conclusions

The results revealed that total Polyphyllin treated GC through multiple targets, multiple channels, and multiple pathways. In addition, Polyphyllin Ⅲ played an anti-gastric cancer role by inhibiting the proliferation of gastric cancer.

Editorial: Special Issue "Galectins: Structure, Function and Therapeutic Inhibitors"

Galectins, β-galactoside-binding proteins, play relevant roles in different biological processes; therefore, they are becoming emerging targets for diagnostic and therapeutic approaches [...].

Oncological outcomes of conversion therapy in gastric cancer patients with peritoneal metastasis: a large-scale retrospective cohort study

BACKGROUND

Data on the long-term oncological outcomes of patients who undergo conversion surgery (CS) in gastric cancer (GC) patients with peritoneal metastasis (PM) are limited.

METHODS

GC patients with PM who received intraperitoneal (ip) and systemic chemotherapy between April 2015 and January 2021 were enrolled. Multivariate analysis was performed to identify risk factors associated with survival. Clinicopathological and survival outcomes were compared between those with CS and those without CS (NCS). The paclitaxel (PTX) plus tegafur-gimeracil-oteracil potassium capsules (S-1) (PS) + ip PTX and oxaliplatin plus S-1 (SOX) + ip PTX groups were matched in a 1:1 ratio using propensity score matching. Oncological and survival data were collected and analyzed.

RESULTS

A total of 540 patients who received ip chemotherapy via subcutaneous port and systemic chemotherapy were analyzed and 268 patients were enrolled, including 113 who underwent CS and 155 who did not. Overall survival (OS) were 27.0 months and 11.8 months in the CS and NCS groups (P < 0.0001), respectively. R0 resection was an independent prognostic factor for patients who underwent CS. The OS of patients with or without ovariectomy was 21.3 or 12.0 months (P < 0.0001). No difference of clinicopathological and survival outcomes was found between the PS + ip PTX and SOX + ip PTX groups.

CONCLUSION

Conversion therapy is safe and adverse events were manageable. CS improves the survival of GC patients with PM after ip and systemic chemotherapy. R0 is an important prognostic factor. Furthermore, outcomes are comparable between the PS + ip PTX and SOX + ip PTX groups.

Genomic characterization of peritoneal lavage cytology-positive gastric cancer

Objective

Positive peritoneal lavege cytology (CY1) gastric cancer is featured by dismal prognosis, with high risks of peritoneal metastasis. However, there is a lack of evidence on pathogenic mechanism and signature of CY1 and there is a continuous debate on CY1 therapy. Therefore, exploring the mechanism of CY1 is crucial for treatment strategies and targets for CY1 gastric cancer.

Methods

In order to figure out specific driver genes and marker genes of CY1 gastric cancer, and ultimately offer clues for potential marker and risk assessment of CY1, 17 cytology-positive gastric cancer patients and 31 matched cytology-negative gastric cancer patients were enrolled in this study. The enrollment criteria were based on the results of diagnostic laparoscopy staging and cytology inspection of exfoliated cells. Whole exome sequencing was then performed on tumor samples to evaluate genomic characterization of cytology-positive gastric cancer.

Results

Least absolute shrinkage and selection operator (LASSO) algorithm identified 43 cytology-positive marker genes, while MutSigCV identified 42 cytology-positive specific driver genes. CD3G and CDKL2 were both driver and marker genes of CY1. Regarding mutational signatures, driver gene mutation and tumor subclone architecture, no significant differences were observed between CY1 and negative peritoneal lavege cytology (CY0).

Conclusions

There might not be distinct differences between CY1 and CY0, and CY1 might represent the progression of CY0 gastric cancer rather than constituting an independent subtype. This genomic analysis will thus provide key molecular insights into CY1, which may have a direct effect on treatment recommendations for CY1 and CY0 patients, and provides opportunities for genome-guided clinical trials and drug development.

Bone metastasis is a late-onset and unfavorable event in survivors of gastric cancer after radical gastrectomy: Results from a clinical observational cohort

Background

The timing and incidence of recurrent bone metastasis (BM) after radical gastrectomy in patients with gastric cancer (GC) as well as the survival of these patients were not fully understood. The aim of this study was to analyze the data of an observational GC cohort and identify patients who underwent curative gastrectomy and had recurrent BM to describe and clarify the pattern and profile of BM evolution after surgery.

Methods

Data were retrieved from a hospital-based GC cohort, and patients who underwent upfront radical gastrectomy were selected. The time points of specific organ metastatic events were recorded, and the person-year incidence rate of metastatic events was calculated. The latency period of BM events after gastrectomy was measured and compared with that of the other two most common metastatic events, liver metastasis (LM) and distant lymph node metastasis (LNM), using analysis of variance. Propensity score matching and subgroup analysis were used for sensitivity analysis.

Results

A total of 1324 GC cases underwent radical gastrectomy between January 2011 and December 2021. Of these, 67 BM, 218 LM, and 248 LNM occurred before the last follow-up. The incidence of BM events was 1.7/100 person-years, which was approximately 3-fold lower than that of LM and distant LNM events (5.5 and 6.3 per 100 person-years, respectively). BM events had a significantly longer latency (median time, 16.5 months) than LM and LNM events (11.1 and 12.0 months, respectively). Recurrent BM led to a worse prognosis (median survival, 4.5 months) than those of LM and LNM events (median survival, 7.7 and 7.1 months, respectively). However, no difference in overall survival after gastrectomy was observed among the groups.

Conclusions

Compared with other common metastatic events, BM in GC after gastrectomy is a late-onset event indicating poor survival.

Trial registration

No. ChiCTR1800019978; http://www.chictr.org.cn/.

Real-World Data on Second-Line Therapy with Ramucirumab for Metastatic Gastric Cancer: A Two-Center Study on Romanian Population

(1) Background: Following the results of RAINBOW and REGARD trials, ramucirumab was approved as the standard second-line treatment for patients with advanced or metastatic gastric or gastroesophageal junction (GEJ) cancer, alone or in combination with paclitaxel. The present study aimed to evaluate the efficacy and safety of ramucirumab in the Romanian population during every-day clinical practice. (2) Methods: A two-center, retrospective, observational study evaluated patients with metastatic gastric and GEJ cancer treated with ramucirumab monotherapy or associated with paclitaxel. The patients were treated between 2018 and 2022 in two Romanian centers as follows: 18 patients underwent treatment with ramucirumab monotherapy, while 51 received the combined treatment regimen. Study endpoints included median progression-free survival (PFS), median overall survival (OS), and the evaluation of treatment-induced adverse events (AEs). (3) Results: In the study cohort (n = 69), the most frequent treatment-induced AE in the ramucirumab plus paclitaxel arm was hematological toxicity; the most common AE for patients treated with ramucirumab monotherapy was fatigue and headache. Overall, the median PFS was 4.7 months (95% CI: 3.4-5.9 months) and median OS was 18.23 months (95% CI: 15.6-20.7 months). PFS was correlated with the number of treatment cycle administrations, Eastern Cooperative Oncology Group performance status at treatment initiation, and metastatic site (visceral vs. peritoneal). OS was correlated with the number of treatment cycles administered and human epidermal growth factor receptor-2 status. (4) Conclusions: The results support the previously described toxicity profile for ramucirumab monotherapy or associated with paclitaxel and demonstrated a relatively superior median PFS.

Systematic review of diagnostic tools for peritoneal metastasis in gastric cancer-staging laparoscopy and its alternatives

BACKGROUND

Gastric cancer is one of the leading causes of cancer burden and mortality, often resulting in peritoneal metastasis in advanced stages with negative survival outcomes. Staging laparoscopy has become standard practice for suspected cases before a definitive gastrectomy or palliation. This systematic review aims to compare the efficacy of other diagnostic modalities instead of staging laparoscopy as the alternatives are able to reduce cost and invasive staging procedures. Recently, a radiomic model based on computed tomography and positron emission tomography (PET) has also emerged as another method to predict peritoneal metastasis.

AIM

To determine if the efficacy of computed tomography, magnetic resonance imaging and PET is comparable with staging laparoscopy.

METHODS

Articles comparing computed tomography, PET, magnetic resonance imaging, and radiomic models based on computed tomography and PET to staging laparoscopies were filtered out from the Cochrane Library, EMBASE, PubMed, Web of Science, and Reference Citations Analysis (https://www.referencecitationanalysis.com/). In the search for studies comparing computed tomography (CT) to staging laparoscopy, five retrospective studies and three prospective studies were found. Similarly, five retrospective studies and two prospective studies were also included for papers comparing CT to PET scans. Only one retrospective study and one prospective study were found to be suitable for papers comparing CT to magnetic resonance imaging scans.

RESULTS

Staging laparoscopy outperformed computed tomography in all measured aspects, namely sensitivity, specificity, positive predictive value and negative predictive value. Magnetic resonance imaging and PET produced mixed results, with the former shown to be only marginally better than computed tomography. CT performed slightly better than PET in most measured domains, except in specificity and true negative rates. We speculate that this may be due to the limited F-fluorodeoxyglucose uptake in small peritoneal metastases and in linitis plastica. Radiomic modelling, in its current state, shows promise as an alternative for predicting peritoneal metastases. With further research, deep learning and radiomic modelling can be refined and potentially applied as a preoperative diagnostic tool to reduce the need for invasive staging laparoscopy.

CONCLUSION

Staging laparoscopy was superior in all measured aspects. However, associated risks and costs must be considered. Refinements in radiomic modelling are necessary to establish it as a reliable screening technique.

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) with cisplatin and doxorubicin in combination with FOLFOX chemotherapy as a first-line treatment for gastric cancer patients with peritoneal metastases: single-arm phase II study

BACKGROUND

Gastric cancer (GC) remains among the most common and most lethal cancers worldwide. Peritoneum is the most common site for distant dissemination. Standard treatment for GC peritoneal metastases (PM) is a systemic therapy, but treatment outcomes remain very poor, with median overall survival ranging between 3-9 months. Thus, novel treatment methods are necessary. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is the most novel technique for intraperitoneal chemotherapy. Some preliminary data suggest PIPAC can achieve improved long-term outcomes in patients with GC PM, especially when used in combination with systemic chemotherapy. However, there is a lack of data from well-design prospective studies that would confirm the efficacy of PIPAC and systemic therapy combination for first-line treatment.

METHODS

This study is an investigator-initiated single-arm, phase II trial to investigate the efficacy of PIPAC combined with systemic FOLFOX (5-fluorouracil, oxaliplatin, leucovorin) as a first-line treatment for GC PM. The study is conducted in 2 specialized GC treatment centers in Lithuania. It enrolls GC patients with histologically confirmed PM without prior treatment. The treatment protocol consists of PIPAC with cisplatin (10.5 mg/m2 body surface in 150 mL NaCl 0.9%) and doxorubicin (2.1 mg/m2 in 50 mL NaCl 0.9%) followed by 2 cycles of FOLFOX every 6-7 weeks. In total 3 PIPACs and 6 cycles of FOLFOX will be utilized. The primary outcome of the study is the objective response rate (ORR) according to RECIST v. 1.1 criteria (Eisenhauer et al., Eur J Cancer 45:228-47) in a CT scan performed 7 days after the 4th cycle of FOLFOX. Secondary outcomes include ORR after all experimental treatment, PIPAC characteristics, postoperative morbidity, histological and biochemical response, ascites volume, quality of life, overall survival, and toxicity.

DISCUSSION

This study aims to assess PIPAC and FOLFOX combination efficacy for previously untreated GC patients with PM.

TRIAL REGISTRATION

NCT05644249. Registered on December 9, 2022.

Malignant ascites supernatant enhances the proliferation of gastric cancer cells partially via the upregulation of asparagine synthetase

Malignant ascites (MA) is a common manifestation of advanced gastric cancer (GC) with peritoneal metastasis (PM), which usually indicates a poor prognosis. The present study aimed to explore the effects of MA, a unique microenvironment of PM, on the proliferation of cancer cells and investigate the underlying mechanisms. Ex vivo experiments demonstrated that GC cells treated with MA exhibited enhanced proliferation. RNA sequencing indicated that asparagine synthetase (ASNS) was one of the differentially expressed genes in GC cells following incubation with MAs. Furthermore, the present study suggested that MA induced an upregulation of ASNS expression and the stimulatory effect of MA on cancer cell proliferation was alleviated upon ASNS downregulation. Activating transcription factor 4 (ATF4), a pivotal transcription factor regulating ASNS, was upregulated when cells were treated with MA supernatant. After ATF4 knockdown, the proliferation of MA-treated GC cells and the expression of ASNS decreased. In addition, the decline in the proliferation of the ATF4-downregulated AGS GC cell line was rescued by ASNS upregulation. The findings indicated that MA could promote the proliferation of GC cells via activation of the ATF4-ASNS axis. Hence, it may be a potential target for treating GC with PM and MA.

Hyperthermic intraperitoneal chemotherapy (HIPEC) plus systemic chemotherapy versus systemic chemotherapy alone in locally advanced gastric cancer after D2 radical resection: a randomized-controlled study

BACKGROUND

Currently, there is a lack of an effective strategy for the prevention of peritoneal metastasis (PM) from locally advanced gastric cancer (AGC). This randomized-controlled study aimed to evaluate the outcome of D2 radical resection with hyperthermic intraperitoneal chemotherapy (HIPEC) plus systemic chemotherapy versus systemic chemotherapy alone in locally AGC patients.

METHODS

All enrolled patients were randomly assigned to receive HIPEC plus systemic chemotherapy (HIPEC group) or systemic chemotherapy alone (non-HIPEC group) after radical gastrectomy. HIPEC was performed intraperitoneally with cisplatin (40 mg/m2) within 72 h after surgery, while systemic chemotherapy based on the SOX regimen (S-1 combined with oxaliplatin) was administered 4-6 weeks after radical surgery. Patterns of recurrence, adverse events, 3-year disease-free survival (DFS), and overall survival (OS) were analyzed.

RESULTS

A total of 134 patients were enrolled in the present study. The 3-year DFS rate was 73.8% in the HIPEC group, which was significantly higher than that in the non-HIPEC group (61.2%, P = 0.031). The 3-year OS rate was 73.9% in the HIPEC group and 77.6% in the non-HIPEC group, with no significant difference (P = 0.737). PM was the most common distant metastasis in both groups. The occurrence rate of PM in the HIPEC group was statistically lower than that in the non-HIPEC group (20.9% vs. 40.3%, P = 0.015). Grade 3 or 4 adverse events occurred in 19 (14.2%) patients, and there was no significant difference between the two groups.

CONCLUSION

Radical surgery followed by HIPEC combined with systemic chemotherapy is a safe and feasible strategy for locally AGC patients and could effectively improve DFS and reduce the occurrence of PM. However, more prospective randomized studies with a large sample size are warranted.

TRIAL REGISTRATION

This study was registered with www.medresman.org.cn as ChiCTR2200055966 on 10/12/2016.

Galectin-4 Is Involved in the Structural Changes of Glycosphingolipid Glycans in Poorly Differentiated Gastric Cancer Cells with High Metastatic Potential

Gastric cancer with peritoneal dissemination is difficult to treat surgically, and frequently recurs and metastasizes. Currently, there is no effective treatment for this disease, and there is an urgent need to elucidate the molecular mechanisms underlying peritoneal dissemination and metastasis. Our previous study demonstrated that galectin-4 participates in the peritoneal dissemination of poorly differentiated gastric cancer cells. In this study, the glycan profiles of cell surface proteins and glycosphingolipids (GSLs) of the original (wild), galectin-4 knockout (KO), and rescue cells were investigated to understand the precise mechanisms involved in the galectin-4-mediated regulation of associated molecules, especially with respect to glycosylation. Glycan analysis of the NUGC4 wild type and galectin-4 KO clones with and without peritoneal metastasis revealed a marked structural change in the glycans of neutral GSLs, but not in N-glycan. Furthermore, mass spectrometry (MS) combined with glycosidase digestion revealed that this structural change was due to the presence of the lacto-type (β1-3Galactosyl) glycan of GSL, in addition to the neolacto-type (β1-4Galactosyl) glycan of GSL. Our results demonstrate that galectin-4 is an important regulator of glycosylation in cancer cells and galectin-4 expression affects the glycan profile of GSLs in malignant cancer cells with a high potential for peritoneal dissemination.

INTRAPERITONEAL CHEMOTHERAPY FOR GASTRIC CANCER WITH PERITONEAL CARCINOMATOSIS: STUDY PROTOCOL OF A PHASE II TRIAL

BACKGROUND

Peritoneal carcinomatosis in gastric cancer is considered a fatal disease, without expectation of definitive cure. As systemic chemotherapy is not sufficient to contain the disease, a multimodal approach associating intraperitoneal chemotherapy with surgery may represent an alternative for these cases.

AIMS

The aim of this study was to investigate the role of intraperitoneal chemotherapy in stage IV gastric cancer patients with peritoneal metastasis.

METHODS

This study is a single institutional single-arm prospective clinical trial phase II (NCT05541146). Patients with the following inclusion criteria undergo implantation of a peritoneal catheter for intraperitoneal chemotherapy: Stage IV gastric adenocarcinoma; age 18-75 years; Peritoneal carcinomatosis with peritoneal cancer index<12; Eastern Cooperative Oncology Group 0/1; good clinical status; and lab exams within normal limits. The study protocol consists of four cycles of intraperitoneal chemotherapy with paclitaxel associated with systemic chemotherapy. After treatment, patients with peritoneal response assessed by staging laparoscopy undergo conversion gastrectomy.

RESULTS

The primary outcome is the rate of complete peritoneal response. Progression-free and overall survivals are other outcomes evaluated. The study started in July 2022, and patients will be screened for inclusion until 30 are enrolled.

CONCLUSIONS

Therapies for advanced gastric cancer patients have been evaluated in clinical trials but without success in patients with peritoneal metastasis. The treatment proposed in this trial can be promising, with easy catheter implantation and ambulatory intraperitoneal chemotherapy regime. Verifying the efficacy and safety of paclitaxel with systemic chemotherapy is an important progress that this study intends to investigate.

CXCL8 and the peritoneal metastasis of ovarian and gastric cancer

CXCL8 is the most representative chemokine produced autocrine or paracrine by tumor cells, endothelial cells and lymphocytes. It can play a key role in normal tissues and tumors by activating PI3K-Akt, PLC, JAK-STAT, and other signaling pathways after combining with CXCR1/2. The incidence of peritoneal metastasis in ovarian and gastric cancer is extremely high. The structure of the peritoneum and various peritoneal-related cells supports the peritoneal metastasis of cancers, which readily produces a poor prognosis, low 5-year survival rate, and the death of patients. Studies show that CXCL8 is excessively secreted in a variety of cancers. Thus, this paper will further elaborate on the mechanism of CXCL8 and the peritoneal metastasis of ovarian and gastric cancer to provide a theoretical basis for the proposal of new methods for the prevention, diagnosis, and treatment of cancer peritoneal metastasis.

Peritoneal Carcinosis: What the Radiologist Needs to Know

Peritoneal carcinosis is a condition characterized by the spread of cancer cells to the peritoneum, which is the thin membrane that lines the abdominal cavity. It is a serious condition that can result from many different types of cancer, including ovarian, colon, stomach, pancreatic, and appendix cancer. The diagnosis and quantification of lesions in peritoneal carcinosis are critical in the management of patients with the condition, and imaging plays a central role in this process. Radiologists play a vital role in the multidisciplinary management of patients with peritoneal carcinosis. They need to have a thorough understanding of the pathophysiology of the condition, the underlying neoplasms, and the typical imaging findings. In addition, they need to be aware of the differential diagnoses and the advantages and disadvantages of the various imaging methods available. Imaging plays a central role in the diagnosis and quantification of lesions, and radiologists play a critical role in this process. Ultrasound, computed tomography, magnetic resonance, and PET/CT scans are used to diagnose peritoneal carcinosis. Each imaging procedure has advantages and disadvantages, and particular imaging techniques are recommended based on patient conditions. Our aim is to provide knowledge to radiologists regarding appropriate techniques, imaging findings, differential diagnoses, and treatment options. With the advent of AI in oncology, the future of precision medicine appears promising, and the interconnection between structured reporting and AI is likely to improve diagnostic accuracy and treatment outcomes for patients with peritoneal carcinosis.

Highly Sensitive Circulating Tumor DNA Assay Aids Clinical Management of Radiographically Occult Isolated Peritoneal Metastases in Patients With GI Cancer

PURPOSE

GI cancers commonly spread to the peritoneal cavity, particularly from primary adenocarcinomas of the stomach and appendix. Peritoneal metastases are difficult to visualize on cross-sectional imaging and cause substantial morbidity and mortality. The purpose of this study was to determine whether serial highly sensitive tumor-informed circulating tumor DNA (ctDNA) measurements could longitudinally track changes in disease burden and inform clinical care.

METHODS

This was a retrospective case series of patients with gastric or appendiceal adenocarcinoma and isolated peritoneal disease that was radiographically occult. Patients underwent quantitative tumor-informed ctDNA testing (Signatera) as part of routine clinical care. No interventions were prespecified based on ctDNA results.

RESULTS

Of 13 patients studied, the median age was 65 (range, 45-75) years, with 7 (54%) women, 5 (38%) patients with gastric, and 8 (62%) patients with appendiceal adenocarcinoma. Eight (62%) patients had detectable ctDNA at baseline measurement, with median value 0.13 MTM/mL (range, 0.06-11.68), and assay was technically unsuccessful in two cases with appendiceal cancer because of limited tumor tissue. Five (100%) patients with gastric cancer and 3 (50%) patients with appendiceal cancer had detectable ctDNA at baseline. Although baseline levels of ctDNA were low, longitudinal assessment tracked with changes in disease burden among patients undergoing chemotherapy for metastatic disease. In two patients undergoing surveillance after definitive surgical management of gastric adenocarcinoma, detection of ctDNA prompted diagnosis of isolated peritoneal disease.

CONCLUSION

Quantitative tumor-informed serial ctDNA testing aids clinical management of patients with isolated peritoneal disease. Low levels of baseline ctDNA suggest a role for highly sensitive ctDNA approaches over panel-based testing. Further exploration of this approach should be considered in patients with isolated peritoneal malignant disease.

Targeting ROR1 Inhibits Glucocorticoid-induced Gastric Cancer Metastasis

Glucocorticoids are commonly used in clinic but are also a double-edged sword. While treating tumors, they are reported to promote tumor growth and metastasis. To explore the role and elucidate the mechanism of dexamethasone in promoting tumor growth and metastasis, we detected the levels of cortisol and adrenocorticotropic hormone (ACTH) in peripheral blood of patients with gastric cancer, and immunohistochemical staining was used to detect the expression of GR and ROR1 in the surgically resected gastric cancer samples. The levels of cortisol and ACTH in peripheral blood of patients with stage III and IV gastric cancer were higher than those of patients with stage I/II gastric cancer. Dexamethasone up-regulated the ROR1 level on gastric cancer cell lines in a concentration-dependent manner. Gastric cancer specimen with high ROR1 had higher rates of relapse and metastasis than gastric adenocarcinomas expressing low levels of ROR1.Gastric cancer patients with high expression of ROR1 had a short survival time. ROR1 was expressed by gastric cancer cell lines, but not on normal gastric epithelial cell line. Suppressing ROR1 in gastric cancer cell lines impaired their invasion, migration, scratch healing and clone formation ability in vitro and slowed down the tumor growth of MKN-45 cells in immunodeficient mice in vivo. Collectively, our study indicated that dexamethasone up-regulated ROR1 levels on gastric cancer cells. ROR1 participated in and mediated the role of dexamethasone in promoting gastric tumor growth, and blocking ROR1 can prevent the tumor growth.

Preoperative neutrophil-to-platelet ratio as a potential prognostic factor for gastric cancer with positive peritoneal lavage cytology in the absence of other non-curative factors: a multi-institutional dataset analysis

PURPOSE

Peritoneal dissemination is the key to the prognosis of gastric cancer (GC) and can be detected early with peritoneal lavage cytology. No studies have examined preoperative prognostic factors in GC patients who have positive cytology but no other non-curative factors.

METHODS

We conducted a retrospective analysis using a multicenter database of 3575 patients who underwent gastrectomy between 2010 and 2014. Patients with positive peritoneal lavage cytology as a sole non-curative factor were retrieved, and correlations between parameters and the prognosis were compared.

RESULTS

A total of 66 patients were identified as eligible. In the receiver operating characteristic (ROC) curve analysis, the neutrophil-to-platelet ratio (NPR) had the greatest area under the curve value and was selected. We divided the NPR into two groups based on the optimal cutoff value of the NPR (2.000), as determined by the ROC curve analysis. A high preoperative NPR was the only prognostic factor. The NPR-high group had shorter overall survival than the NPR-low group (hazard ratio 1.85, 95% confidence interval 1.05-3.28, P = 0.032).

CONCLUSION

Our analysis indicated that the preoperative NPR serves as a prognostic factor in GC patients with positive peritoneal lavage cytology in the absence of other non-curative factors.

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.

Gastric cancer clinical characteristics and their altered trends in South China: An epidemiological study with 2,800 cases spanning 26 years

BACKGROUND

Gastric cancer (GC) is a serious threat to human health. The clinical GC characteristics in China may be impacted by changes in people's lifestyles and the promotion of early GC (EGC) screening. The present study aims to evaluate the recent trends of GC characteristics in South China and search for hazardous factors limiting the survival time of GC patients.

METHODS

Data on GC patients that were hospitalized in the Department of Digestive Center, the First Affiliated Hospital, Sun Yat-sen University, from 1994 to 2019 were collected and divided into two categories according to the time when the EGC screening began in China: the PRE group (previous 13 years, 1994-2006) and the PAS group (past 13 years, 2007-2019).

RESULTS

We found that, although the 5-year survival rate increased in the PAS group compared with the PRE group (P < 0.0001), patients with age ≥60 years or Borrmann type IV still had a worse prognosis. In the PAS group, the larger percentages of elderly patients and patients with Borrmann type IV in the lymphatic metastases (N1) group (41.0% vs. 51.1%, P = 0.0014) and stage IV subgroup (20.7% vs. 32.2%, P = 0.016), respectively, when compared with the PRE group, may have contributed to the poor outcome of GC. By comparing the odds ratio (OR) of 5-year overall survival (OS) in the two 13-year periods, female sex and T2 turned into risk factors because of a greater proportion of Borrmann type IV or elderly patients in the PAS group (OR = 0.983, 95% CI = 0.723-1.336 vs. OR = 1.277, 95% CI = 1.028-1.586 and OR = 1.545, 95% CI = 0.499-4.775 vs. OR = 2.227, 95% CI = 1.124-4.271, respectively).

CONCLUSIONS

Despite the GC epidemiology changes, the overall prognosis of GC patients has improved in South China. However, old age and Borrmann type IV are still the major restrictions affecting the survival of GC patients, a situation which calls for additional attention.

Targeting myeloid villains in the treatment with immune checkpoint inhibitors in gastrointestinal cancer

Despite the clinical outcomes being extremely limited, blocking immune inhibitory checkpoint pathways has been in the spotlight as a promising strategy for treating gastrointestinal cancer. However, a distinct strategy for the successful treatment is obviously needed in the clinical settings. Myeloid cells, such as neutrophils, macrophages, dendritic cells, and mast cells, are the majority of cellular components in the human immune system, but have received relatively less attention for the practical implementation than T cells and NK cells in cancer therapy because of concentration of the interest in development of the immune checkpoint blocking antibody inhibitors (ICIs). Abnormality of myeloid cells must impact on the entire host, including immune responses, stromagenesis, and cancer cells, leading to refractory cancer. This implies that elimination and reprogramming of the tumor-supportive myeloid villains may be a breakthrough to efficiently induce potent anti-tumor immunity in cancer patients. In this review, we provide an overview of current situation of the IC-blocking therapy of gastrointestinal cancer, including gastric, colorectal, and esophageal cancers. Also, we highlight the possible oncoimmunological components involved in the mechanisms underlying the resistance to the ICI therapy, particularly focusing on myeloid cells, including unique subsets expressing IC molecules. A deeper understanding of the molecular and cellular determinants may facilitate its practical implementation of targeting myeloid villains, and improve the clinical outcomes in the ICI therapy of gastrointestinal cancer.

Management of positive peritoneal cytology gastric cancer patients

Prognosis of patients with stage IV gastric cancer remains up to date dramatically poor. A subgroup of these patients has only positive peritoneal cytology in the peritoneal lavage and represents a target issue of the recent ongoing research. The administration of neoadjuvant chemotherapy, either systemic or intraperitoneal or hyperthermic intraoperative peritoneal chemotherapy, with a variety of combinations of drugs has assisted some of these patients to become peritoneal cytology negative, with a significant implication in their prognosis. Staging laparoscopy is widely used to detect occult peritoneal disease and has, therefore, reduced the number of unnecessary laparotomies. However, recent reports point out a low sensitivity of staging laparoscopy and cytological exam in detecting viable cancer cells and focus on the need of more accurate methods of examining the peritoneal fluid by immunohistochemistry or molecular assays. This review focuses on the latest scientific evidence regarding the optimal management of positive peritoneal cytology gastric cancer patients.

Efficacy of AS versus SOX regimen as first-line chemotherapy for gastric cancer patients with peritoneal metastasis: a real-world study

Background

To compare the prognosis of first-line systemic chemotherapy of AS (Albumin-bound paclitaxel and S-1) versus SOX (S-1 and oxaliplatin) regimen in Chinese gastric cancer patients with peritoneal metastasis.

Methods

This was a real-world study of gastric cancer patients with peritoneal metastasis who have been treated with AS or SOX regimen as first-line chemotherapy. Patients were matched by the method of propensity score matching (PSM). The primary and secondary endpoints were overall survival (OS) and progress-free survival (PFS).

Results

A total of 108 gastric cancer patients with peritoneal metastasis were enrolled after PSM analysis. There was no significant difference between AS and SOX regimen based on gender, age, ascites, treatment cycles, gastric cancer resection, received checkpoint inhibitors, and HER-2 expression after PSM analysis. The median OS (14.13 vs. 11.17 months, p = 0.0356) and median PFS (10.30 vs. 6.70 months, p = 0.0003) of patients who received AS regimen were longer than those treated by SOX regimen as first-line systemic chemotherapy. In sub-group analysis, the median OS and median PFS were longer for patients in AS regimen than SOX regimen in Lauren diffuse type. The occurrence of toxicity between the two groups was shown no significant difference.

Conclusions

The results verified that AS regimen was more effective than SOX chemotherapy in gastric cancer patients with peritoneal metastasis, especially in Lauren diffuse type.

Safety and Efficacy of Intraperitoneal Paclitaxel Plus Intravenous Fluorouracil, Leucovorin, and Oxaliplatin (FOLFOX) for Gastric Cancer with Peritoneal Metastasis

BACKGROUND

Peritoneal metastasis (PM) remains a major obstacle in the treatment of stage IV gastric cancer. This is a dose-escalation study of intraperitoneal (IP) paclitaxel combined with intravenous (IV) fluorouracil, leucovorin, and oxaliplatin (FOLFOX) to determine the recommended phase II dose in gastric cancer patients.

METHODS

Patients with gastric adenocarcinoma and PM were enrolled. The recommended phase II dose of IP paclitaxel was determined using the standard "3 + 3" dose escalation with planned doses ranging from 40 to 100 mg/m². IV FOLFOX was administered on the same day (oxaliplatin 100 mg/m² (day 1), leucovorin 100 mg/m² (day 1), fluorouracil 2,400 mg/m² over 46 hours (day 1)). Both IP and IV regimens were repeated every 2 weeks.

RESULTS

Among the 13 patients, there was no DLT at 40 and 60 mg/m². Two patients had grade 3 febrile neutropenia at 80 mg/m², and the recommended phase II dose was 60 mg/m². Other patients underwent IP paclitaxel and FOLFOX without serious adverse events. Seven patients underwent second-look diagnostic laparoscopy, and the average change in PCI score was -7.0 ± 9.7. Conversion surgery rate was 23.1% (n = 3). The median overall survival was 16.6 months (95% confidence interval, 16.6-N/A), and progression-free survival was 9.6 months (95% confidence interval, 4.7-N/A). All adverse events were tolerable and manageable.

CONCLUSIONS

The biweekly regimen of IP paclitaxel and FOLFOX is safe and the recommended dose of IP paclitaxel for a phase II trial is 60 mg/m².

Oncolytic Virotherapy in Peritoneal Metastasis Gastric Cancer: The Challenges and Achievements

Gastric cancer (GC) is the fourth most common cancer and the second leading cause of cancer death globally. Although the mortality rate in some parts of the world, such as East Asia, is still high, new treatments and lifestyle changes have effectively reduced deaths from this type of cancer. One of the main challenges of this type of cancer is its late diagnosis and poor prognosis. GC patients are usually diagnosed in the advanced stages of the disease, which is often associated with peritoneal metastasis (PM) and significantly reduces survival. This type of metastasis in patients with GC poses a serious challenge due to limitations in common therapies such as surgery and tumor resection, as well as failure to respond to systemic chemotherapy. To solve this problem, researchers have used virotherapy such as reovirus-based anticancer therapy in patients with GC along with PM who are resistant to current chemotherapies because this therapeutic approach is able to overcome immune suppression by activating dendritic cells (DCs) and eventually lead to the intrinsic activity of antitumor effector T cells. This review summarizes the immunopathogenesis of peritoneal metastasis of gastric cancer (PMGC) and the details for using virotherapy as an effective anticancer treatment approach, as well as its challenges and opportunities.

Clinical significance of initial treatment for peritoneal lavage cytology-positive gastric cancer: outcomes according to treatment strategy

Background

Although patients with positive lavage cytology (CY1) are classified as having stage IV disease, long-term survival without other unresectable factors (P0CY1) has been reported. Conversion gastrectomy in patients with a change in cytology status after induction chemotherapy might improve survival, but appropriate treatment remains controversial. Here, we reviewed our experience in treating CY1 gastric cancer to evaluate the best treatment strategy.

Methods

Clinical and pathological findings of patients with a diagnosis of P0CY1 gastric cancer at Toranomon Hospital between February 2006 and April 2019 were retrospectively analyzed. Patients were classified into two groups according to initial treatment: a surgery-first group and a chemotherapy-first group. In addition, the patients were categorized into subgroups based on the subsequent treatment pattern. The surgery-first group was divided into two subgroups: adjuvant chemotherapy and palliative gastrectomy only. The chemotherapy-first group was divided into three subgroups with the subsequent treatment pattern depending on the response to chemotherapy: conversion gastrectomy, palliative gastrectomy after induction therapy, and palliative chemotherapy.

Results

In total, 38 patients were eligible for inclusion in this study. After initial assessment of cytology status, 21 patients underwent gastrectomy as initial treatment (surgery first) and 17 received induction chemotherapy (chemotherapy first). Ten patients underwent surgery first with adjuvant chemotherapy, 11 underwent palliative gastrectomy alone, 5 underwent conversion surgery, 5 with CY1 disease after induction chemotherapy underwent palliative gastrectomy, and 7 received palliative chemotherapy only. The 3-year survival rate was 23.4% (median survival, 17.7 months) in the surgery-first group and 27.3% (median survival, 19.7 months) in the chemotherapy-first group. The 3-year survival rate was 75% for conversion gastrectomy, 16.7% for palliative chemotherapy, and 0% for palliative gastrectomy after induction chemotherapy.

Conclusions

There was no significant difference in outcome according to whether surgery or chemotherapy was performed first. The prognosis of conversion surgery with curative resection was better than that of the other types of treatment. However, the outlook after induction chemotherapy was poor. Patients with advanced gastric cancer should be treated cautiously until more effective treatment options become available.

Extracellular Vesicles Promote the Formation of Pre-Metastasis Niche in Gastric Cancer

Globally, gastric cancer (GC) ranks fourth in the incidence of malignant tumors. The early clinical manifestations of GC lack specificity. Most patients are already at an advanced stage when they are first diagnosed, and their late progression is mainly due to peritoneal metastasis. A pre-metastatic microenvironment is formed, before the macroscopic tumor metastasis. Extracellular vesicles (EVs) are nanovesicles released by cells into body fluids. Recent studies have shown that EVs can affect the tumor microenvironment by carrying cargos to participate in cell-to-cell communication. EVs derived from GC cells mediate the regulation of the pre-metastasis niche and act as a coordinator between tumor cells and normal stroma, immune cells, inflammatory cells, and tumor fibroblasts to promote tumor growth and metastasis. This review highlights the regulatory role of EVs in the pre-metastatic niche of GC and mulls EVs as a potential biomarker for liquid biopsy.

The Development of Peritoneal Metastasis from Gastric Cancer and Rationale of Treatment According to the Mechanism

In the present article, we describe the normal structure of the peritoneum and review the mechanisms of peritoneal metastasis (PM) from gastric cancer (GC). The structure of the peritoneum was studied by a double-enzyme staining method using alkaline-phosphatase and 5'-nucreotidase, scanning electron microscopy, and immunohistological methods. The fundamental structure consists of three layers, mesothelial cells and a basement membrane (layer 1), macula cribriformis (MC) (layer 2), and submesothelial connective tissue containing blood vessels and initial lymphatic vessels, attached to holes in the MC (layer 3). Macro molecules and macrophages migrate from mesothelial stomata to the initial lymphatic vessels through holes in the MC. These structures are characteristically found in the diaphragm, omentum, paracolic gutter, pelvic peritoneum, and falciform ligament. The first step of PM is spillage of cancer cells (peritoneal free cancer cells; PFCCs) into the peritoneal cavity from the serosal surface of the primary tumor or cancer cell contamination from lymphatic and blood vessels torn during surgical procedures. After PFCCs adhere to the peritoneal surface, PMs form by three processes, i.e., (1) trans-mesothelial metastasis, (2) trans-lymphatic metastasis, and (3) superficial growing metastasis. Because the intraperitoneal (IP) dose intensity is significantly higher when generated by IP chemotherapy than by systemic chemotherapy, IP chemotherapy has a great role in the treatment of PFCCs, superficial growing metastasis, trans-lymphatic metastasis and in the early stages of trans-mesothelial metastasis. However, an established trans-mesothelial metastasis has its own interstitial tissue and vasculature which generate high interstitial pressure. Accordingly, it is reasonable to treat established trans-mesothelial metastasis by bidirectional chemotherapy from both IP and systemic chemotherapy.

Exploration of predictors of benefit from nivolumab monotherapy for patients with pretreated advanced gastric and gastroesophageal junction cancer: post hoc subanalysis from the ATTRACTION-2 study

BACKGROUND

The phase 3 ATTRACTION-2 study demonstrated that nivolumab monotherapy was superior to placebo for patients with pretreated advanced gastric or gastroesophageal junction cancer, but early progression of tumors in some patients was of concern.

METHODS

This post hoc analysis statistically explored the baseline characteristics of the ATTRACTION-2 patients and extracted a single-factor and double-factor combinations associated with early disease progression or early death. In the extracted patient subgroups, the 3-year restricted mean survival times of progression-free survival and overall survival were compared between the nivolumab and placebo arms.

RESULTS

Two single factors (age and peritoneal metastasis) were extracted as independent predictors of early progression, but none of them, as a single factor, stratified patients into two subgroups with significant differences in restricted mean survival time. In contrast, two double-factor combinations (serum sodium level and white blood cell count; serum sodium level and neutrophil-lymphocyte ratio) stratifying patients into two subgroups with significant differences in the restricted mean survival time were extracted. Additional exploratory analysis of a triple-factor combination showed that patients aged < 60 years with peritoneal metastasis and low serum sodium levels (approximately 7% of all patients) might receive less benefit from nivolumab, and patients aged ≥ 60 years with no peritoneal metastasis and normal serum sodium levels might receive higher benefit.

CONCLUSIONS

A combination of age, peritoneal metastasis, and serum sodium level might predict benefit from nivolumab as salvage therapy in advanced gastric or gastroesophageal junction cancer patients, especially less benefit for patients having all three risk factors.

The impact of hyperthermic intraperitoneal chemotherapy and cytoreductive surgery on clinical outcomes and quality of life of patients with peritoneal carcinomatosis

AIM OF THE STUDY

To investigate the impact of hyperthermic intraperitoneal chemotherapy (HIPEC) on the clinical and oncological outcomes and quality of life (QOL) of patients with peritoneal carcinomatosis (PC).

MATERIAL AND METHODS

The study involved 304 patients with PC of different origin, who were divided into 2 groups: Group I - cytoreductive surgery (CRS) + adjuvant chemotherapy (ACT) - 247 patients; Group II - CRS + HIPEC + ACT - 57 patients. Intraoperative characteristics and postoperative complications were compared. Patients' QOL was assessed at all phases of treatment using the international scales the Short Form-36 Health Survey (SF-36) and European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire for Breast Cancer Core 30 (EORTC QLQ-C30).

RESULTS

No statistically significant differences were observed between the 2 groups comparing the average blood loss and the total rate of postoperative complications, although the rates of hyperthermia and acute renal failure in the early postoperative period were higher in the HIPEC group. The use of HIPEC significantly contributed to the worse restoration of intestinal function in the postoperative period and to prolonged hospital stay. Assessment of the QOL of patients in Group II using SF-36 showed no significant difference between the physical and psychological components of health compared with the control group. The analysis of EORTC data showed a significant deterioration in the QOL of patients in Group II due to increased scales of pain, nausea and vomiting, and constipation in the early postoperative period. No difference in QOL was observed in the subsequent phases of treatment and after its completion. Overall survival and disease-free survival of patients with ovarian cancer who underwent HIPEC were significantly better compared with CRS + ACT alone.

CONCLUSIONS

The proposed HIPEC technique has demonstrated its clinical safety in the treatment of PC, no long-term negative impact on the QOL of patients, and better oncological results for ovarian cancer.

Targeting AURKA in treatment of peritoneal tumor dissemination in gastrointestinal cancer

Intraperitoneal (i.p.) tumor dissemination and the consequent malignant ascites remain unpredictable and incurable in patients with gastrointestinal (GI) cancer, and practical advances in diagnosis and treatment are urgently needed in the clinical settings. Here, we explored tumor biological and immunological mechanisms underlying the i.p. tumor progression for establishing more effective treatments. We established mouse tumor ascites models that murine and human colorectal cancer cells were both i.p. and subcutaneously (s.c.) implanted in mice, and analyzed peritoneal exudate cells (PECs) obtained from the mice. We then evaluated anti-tumor efficacy of agents targeting the identified molecular mechanisms using the ascites models. Furthermore, we validated the clinical relevancy of the findings using peritoneal lavage fluids obtained from gastric cancer patients. I.p. tumor cells were giant with large nuclei, and highly express AURKA, but less phosphorylated TP53, as compared to s.c. tumor cells, suggesting polyploidy-like cells. The i.p. tumors impaired phagocytic activity and the consequent T-cell stimulatory activity of CD11b⁺Gr1⁺PD1⁺ myeloid cells by GDF15 that is regulated by AURKA, leading to treatment resistance. Blocking AURKA with MLN8237 or siRNAs, however, abrogated the adverse events, and induced potent anti-tumor immunity in the ascites models. This treatment synergized with anti-PD1 therapy. The CD11b⁺PD1⁺ TAMs are also markedly expanded in the PECs of gastric cancer patients. These suggest AURKA is a determinant of treatment resistance of the i.p. tumors. Targeting the AURKA-GDF15 axis could be a promising strategy for improving clinical outcome in the treatment of GI cancer.

Implementation of the enhanced recovery after surgery protocol for patients with peritoneal carcinomatosis undergoing cytoreductive surgery and hyperthermic intraperitoneal chemoperfusion

Aim of the study

To investigate the feasibility of enhanced recovery after surgery (ERAS) protocol for patients with primary peritoneal carcinomatosis (PC) undergoing cytoreductive surgery with hyperthermic intraperitoneal chemoperfusion (HIPEC) based on the length of hospital stay (LOS), return of bowel function, the incidence of postoperative complications, and quality of life (QLQ) analysis.

Material and methods

The study included a total of 37 patients with primary PC of different origin, who underwent cytoreductive surgery plus HIPEC. Patients were divided into 2 groups: Group I (nonERAS) – 20 patients and Group II (ERAS) – 17 patients.

Results

The median LOS in Group I (nonERAS) (12.35 ± 3.9) was longer than in Group II (ERAS) (6.8 ± 1.9) (p < 0.01). The use of the ERAS protocol significantly contributed to the faster return of bowel function (peristalsis and stool) in the postoperative period (p < 0.01). There was no statistically significant difference in the incidence of postoperative complications between the ERAS and nonERAS groups, which supports its clinical safety. Improved QLQ according to the obtained data has also been achieved due to the introduction of the principles of the ERAS protocol.

Conclusions

The obtained results prove the expediency and feasibility of the implementation of the ERAS protocol among patients undergoing cytoreductive surgery in combination with HIPEC.

Gastric cancer with positive peritoneal cytology: survival benefit after induction chemotherapy and conversion to negative peritoneal cytology

Background

The optimal treatment in patients with gastric cancer and peritoneal disease remains controversial. Some guidelines indicate palliative treatment only, while others consider surgical treatment in case of positive lavage cytology (CY+) or limited peritoneal disease. Here, we analyzed the role of peritoneal disease in patients with gastric cancer, and the prognostic relevance of response to neoadjuvant therapy.

Methods

In this retrospective cohort analysis, we analyzed patients with adenocarcinoma of the stomach or esophago-gastric junction from a single center operated between 2011 and 2019. According to histology and lavage cytology, patients were classified into four risk groups: (A) no peritoneal disease, (B) CY+ who converted to negative lavage cytology (CY−) after neoadjuvant chemotherapy, (C) CY+ without conversion after chemotherapy, and (D) patients with visible peritoneal metastasis.

Results

Overall, n = 172 patients were included. At initial presentation, n = 125 (73%) had no peritoneal disease, and about a third of patients (n = 47, 27%) had microscopic or macroscopic peritoneal disease. Among them, n = 14 (8%) were CY+ without visible peritoneal metastasis, n = 9 converted to CY− after chemotherapy, and in n = 5 no conversion was observed. Median overall survival was not reached in patients who had initially no peritoneal disease and in patients who converted after chemotherapy, resulting in 3-year survival rates of 65% and 53%. In contrast, median overall survival was reduced to 13 months (95% CI 8.7–16.7) in patients without conversion and was 16 months (95% CI 12–20.5) in patients with peritoneal metastasis without difference between the two groups (p = .364). The conversion rate from CY+ to CY− was significantly higher after neoadjuvant treatment with FLOT (5-fluorouracil plus leucovorin, oxaliplatin, and docetaxel) compared to ECF (epirubicin, cisplatin, and 5-fluorouracil) (p = 0.027).

Conclusion

Conversion of CY+ to CY− after neoadjuvant chemotherapy with FLOT is a significant prognostic factor for a better overall survival. Surgical treatment in well-selected patients should therefore be considered. However, peritoneal recurrence remains frequent despite conversion, urging for a better local control.

A novel prognostic model based on epithelial-mesenchymal transition-related genes predicts patient survival in gastric cancer

Background

Gastric cancer (GC) represents a major malignancy and is the third deathliest cancer globally. Several lines of evidence indicate that the epithelial-mesenchymal transition (EMT) has a critical function in the development of gastric cancer. Although plentiful molecular biomarkers have been identified, a precise risk model is still necessary to help doctors determine patient prognosis in GC.

Methods

Gene expression data and clinical information for GC were acquired from The Cancer Genome Atlas (TCGA) database and 200 EMT-related genes (ERGs) from the Molecular Signatures Database (MSigDB). Then, ERGs correlated with patient prognosis in GC were assessed by univariable and multivariable Cox regression analyses. Next, a risk score formula was established for evaluating patient outcome in GC and validated by survival and ROC curves. In addition, Kaplan-Meier curves were generated to assess the associations of the clinicopathological data with prognosis. And a cohort from the Gene Expression Omnibus (GEO) database was used for validation.

Results

Six EMT-related genes, including CDH6, COL5A2, ITGAV, MATN3, PLOD2, and POSTN, were identified. Based on the risk model, GC patients were assigned to the high- and low-risk groups. The results revealed that the model had good performance in predicting patient prognosis in GC.

Conclusions

We constructed a prognosis risk model for GC. Then, we verified the performance of the model, which may help doctors predict patient prognosis.

UHPLC-ESI-MS/MS Quantification of Relevant Substrates and Metabolites of the Kynurenine Pathway Present in Serum and Peritoneal Fluid from Gastric Cancer Patients-Method Development and Validation

Metabolites and enzymes involved in the kynurenine pathway (KP) are highly promising targets for cancer treatment, including gastrointestinal tract diseases. Thus, accurate quantification of these compounds in body fluids becomes increasingly important. The aim of this study was the development and validation of the UHPLC-ESI-MS/MS methods for targeted quantification of biologically important KP substrates (tryptophan and nicotinamide) and metabolites(kynurenines) in samples of serum and peritoneal fluid from gastric cancer patients. The serum samples were simply pretreated with trichloroacetic acid to precipitate proteins. The peritoneal fluid was purified by solid-phase extraction before analysis. Validation was carried out for both matrices independently. Analysis of the samples from gastric cancer patients showed different accumulations of tryptophan and its metabolites in different biofluids of the same patient. The protocols will be used for the evaluation of tryptophan and kynurenines in blood and peritoneal fluid to determine correlation with the clinicopathological status of gastric cancer or the disease's prognosis.

High FAM189B Expression and Its Prognostic Value in Patients with Gastric Cancer

The clinical significance of the family with sequence similarity 189 member B (FAM189B) gene remains largely unknown in gastric cancer (GC). A comprehensive investigation combining multiple detection methods was carried out in the current study to unveil the clinical implications and prospective molecular characterization of FAM189B protein and mRNA in GC. The protein level of FAM189B was clearly upregulated in the tumor tissues of GC as compared to noncancerous gastric tissues with 179 GC cases and 147 noncancerous gastric controls assessed by immunohistochemistry. The upregulation of the FAM189B protein was also found in the more deteriorating period of the tumor, as there were increasing trends in the groups of larger tumors, with lymph node metastasis, a further advanced clinical stage, and a higher histological grade. Next, we focused on the mRNA level of FAM189B in GC tissues using various high-throughput data. After the screening of GEO, ArrayExpress, and SRA, we finally achieved 18 datasets, including an RNA sequencing dataset of TCGA. Altogether, 1095 cases of GC tissue samples were collected, with 305 unique examples of noncancerous controls. Concerning the mRNA level of FAM189B in GC, the final standard mean difference (SMD) was 0.46 and the area under the curve (AUC) was 0.79 for the upregulation of FAM189B mRNA, which confirmed that the FAM189B mRNA level was also markedly upregulated in GC tissues and comparable to its protein level. The survival analysis showed that the higher expression of FAM189B was a risk factor for the overall survival, first progression, and postprogression survival of GC. For the Affymetrix ID 1555515_a_at of FAM189B, the higher expression level of FAM189B predicted a lower overall survival, first progression survival, and postprogression survival with the hazard ratio (HR) being 1.56 (1.24, 1.95), 1.69 (1.32, 2.17), and 1.97 (1.5, 2.6), respectively. For the Affymetrix ID 203550_s_at of FAM189B, a similar result could be found with corresponding HR being 1.49 (1.24, 1.8), 1.49 (1.21, 1.83), and 1.66 (1.32, 2.08), respectively. The interaction of MEM, COXPRESdb coexpressed genes, and DEGs of GC finally generated 368 genes, and the pathway of the cell cycle was the top pathway enriched by KEGG. In conclusion, the overexpression of the FAM189B protein and mRNA might enhance the incidence of GC.

The Emerging Role of Liquid Biopsy in Gastric Cancer

(1) Background: Liquid biopsy (LB) is a novel diagnostic method with the potential of revolutionizing the prevention, diagnosis, and treatment of several solid tumors. The present paper aims to summarize the current knowledge and explore future possibilities of LB in the management of metastatic gastric cancer. (2) Methods: This narrative review examined the most recent literature on the use of LB-based techniques in metastatic gastric cancer and the current LB-related clinical trial landscape. (3) Results: In gastric cancer, the detection of circulating cancer cells (CTCs) has been recognized to have a prognostic role in all the disease stages. In the setting of localized disease, cell-free DNA (cfDNA) and circulating tumor DNA (ctDNA) qualitative and quantitative detection have the potential to inform on the risk of cancer recurrence and metastatic dissemination. In addition, gastric cancer-released exosomes may play an essential part in metastasis formation. In the metastatic setting, the levels of cfDNA show a positive correlation with tumor burden. There is evidence that circulating tumor microemboli (CTM) in the blood of metastatic patients is an independent prognostic factor for shorter overall survival. Gastric cancer-derived exosomal microRNAs or clonal mutations and copy number variations detectable in ctDNA may contribute resistance to chemotherapy or targeted therapies, respectively. There is conflicting and limited data on CTC-based PD-L1 verification and cfDNA-based Epstein-Barr virus detection to predict or monitor immunotherapy responses. (4) Conclusions: Although preliminary studies analyzing LBs in patients with advanced gastric cancer appear promising, more research is required to obtain better insights into the molecular mechanisms underlying resistance to systemic therapies. Moreover, validation and standardization of LB methods are crucial before introducing them in clinical practice. The feasibility of repeatable, minimally invasive sampling opens up the possibility of selecting or dynamically changing therapies based on prognostic risk or predictive biomarkers, such as resistance markers. Research is warranted to exploit a possible transforming area of cancer care.

LIMK1 promotes peritoneal metastasis of gastric cancer and is a therapeutic target

Peritoneal metastasis is a common form of metastasis among advanced gastric cancer patients. In this study, we reported the identification of LIM domain kinase 1 (LIMK1) as a promoter of gastric cancer peritoneal metastasis, and its potential to be a therapeutic target of dabrafenib (DAB). Using transcriptomic sequencing of paired gastric cancer peritoneal metastasis, primary tumors, and normal gastric tissues, we first unveiled that LIMK1 is selectively up-regulated in metastatic tumors. Increased LIMK1 in gastric cancer peritoneal metastasis was validated by immunohistochemistry analysis of an independent patient cohort. In vitro functional studies demonstrated that LIMK1 knockout or knockdown significantly inhibited cell migration and invasion of gastric cancer cells. LIMK1 knockout also abrogated peritoneal and liver metastases of gastric cancer cells in nude mice in vivo. Dabrafenib, a small molecule targeting LIMK1, was found to decrease cell migration and invasion of gastric cancer cells in vitro and abolish peritoneal and liver metastasis formation in vivo. Mechanistically, either LIMK1 knockout or Dabrafenib inhibited LIMK1 expression and phosphorylation of its downstream target cofilin. Taken together, our results demonstrated that LIMK1 functions as a metastasis promoter in gastric cancer by inhibiting LIMK1-p-cofilin and that Dabrafenib has the potential to serve as a novel treatment for gastric cancer peritoneal metastasis.

Beyond the Guidelines: The Grey Zones of the Management of Gastric Cancer. Consensus Statements from the Gastric Cancer Italian Network (GAIN)

BACKGROUND

Management of gastric and gastroesophageal junction (GEJ) adenocarcinoma remains challenging, because of the heterogeneity in tumor biology within the upper gastrointestinal tract. Daily clinical practice is full of grey areas regarding the complexity of diagnostic, staging, and therapeutic procedures. The aim of this paper is to provide a guide for clinicians facing challenging situations in routine practice, taking a multidisciplinary consensus approach based on available literature.

METHODS

The GAIN (GAstric cancer Italian Network) group was established with the aims of reviewing literature evidence, discussing key issues in prevention, diagnosis, and management of gastric and GEJ adenocarcinoma, and offering a summary of statements. A Delphi consensus method was used to obtain opinions from the expert panel of specialists.

RESULTS

Forty-nine clinical questions were identified in six areas of interest: role of multidisciplinary team; risk factors; diagnosis; management of early gastric cancer and multimodal approach to localized gastric cancer; treatment of elderly patients with locally advanced resectable disease; and treatment of locally advanced and metastatic cancer.

CONCLUSIONS

The statements presented may guide clinicians in practical management of this disease.

Exosomal NNMT from peritoneum lavage fluid promotes peritoneal metastasis in gastric cancer

Peritoneal metastasis (PM) is the major cause of recurrence in patients with gastric cancer (GC) and is associated with poor prognosis. The oncogenic role of Nicotinamide N-methyltransferase (NNMT) in GC has been reported, but the role of secreted NNMT that is transported by exosomes remains unknown. In this study, exosomes were isolated from GC patients with or without PM and from GC cell line, including GC-114, GC-026, MKN45, and SNU-16 cells. The contents of NNMT were significantly enhanced in exosomes isolated from GC patients with PM compared with those from GC patients without PM. Furthermore, the levels of NNMT were significantly enhanced in exosomes from GC cell lines relative to those from normal human gastric epithelial cell line GES-1 cells. These data indicate that NNMT may be involved in intercellular communication for peritoneal dissemination. Moreover, colocalization of GC-derived exosomal NNMT was found in human peritoneal mesothelial cell line HMrSV5 cells. Additionally, relative to GES-1 exosomes, SNU-16 exosomes significantly activated TGF-β/smad2 signaling in HMrSV5 cells. However, when NNMT was silenced, the activation of TGF-β/smad2 by SNU-16 exosomes was abolished in HMrSV5 cells. We propose that NNMT-containing exosomes derived from GC cells could promote peritoneal metastasis via TGF-β/smad2 signaling.

Extracellular vesicle derived miR-544 downregulates expression of tumor suppressor promyelocytic leukemia zinc finger resulting in increased peritoneal metastasis in gastric cancer

Peritoneal metastasis (PM) is the main cause of poor prognosis in patients with advanced gastric cancer (GC). Increasing evidence has suggested that cancer-associated EVs in body fluids may assist in the diagnosis and treatment of GC. Here, we investigated the role of GC-derived EVs in PM development. Our results demonstrate that expression of the tumor suppressor promyelocytic leukemia zinc finger (PLZF) is decreased in GC tissues and PM lesions from GC patients. PLZF suppression promoted migration and invasion of peritoneal mesothelial HMrSV5 cells, while PLZF overexpression suppressed HMrSV5 cell migration and invasion. Microarray analysis revealed significantly upregulated expression of several miRNAs in EVs isolated from GC patients with PM, including miR-544. The increased miR-544 expression was confirmed in GC tissues and PM-derived EVs. Transfection with miR-544 reduced PLZF expression in HMrSV5 cells, while miR-544 inhibition increased PLZF expression. Incubation of GC cells with peritoneal mesothelial HMrSV5 cells showed that miR-544 could be transferred from GC-derived EVs to peritoneal cells, where it suppressed the PLZF expression. These findings indicate that EV-mediated transfer of miR-544 decreases the PLZF expression in PM lesions, which suggests miR-544 could potentially serve as a diagnostic biomarker and therapeutic target for treatment of GC patients.

Upregulated β-arrestin1 predicts poor prognosis and promotes metastasis via AKT/ERK signaling pathway in gastric cancer

BACKGROUND

β-Arrestins have been found to regulate cell proliferation, invasion and migration; transmit anti-apoptotic survival signals; and affect other characteristics of tumours. However, their role in gastric cancer (GC) is not clear. We investigated the role and mechanism of β-arrestins in the regulation of GC.

METHODS

We first examined β-arrestins mRNA levels in 17 pairs of GC tissues by qRT-PCR. We also used immunohistochemistry to further examine the expression of β-arrestins in 60 paraffin-embedded primary GC tissues and 20 normal gastric tissues. Then, the function of β-arrestin1 was investigated in vitro and in vivo.

RESULTS

β-Arrestin1 was upregulated in GC tissue and was associated with tumour stage, lymph node metastasis, invasion depth and patient sex. High expression of β-arrestin1 expression predicted poor prognosis in GC. β-Arrestin1 promoted GC cell proliferation, migration and invasion, and it suppressed E-cadherin expression and upregulated Vimentin expression via AKT/ERK signalling pathway. The in vivo metastasis assays showed that knockdown of β-arrestin1 reduced lung metastasis and inhibited EMT.

CONCLUSION

The upregulation of β-arrestin1 predicts poor prognosis and promotes metastasis and epithelial-mesenchymal transition in GC through AKT/ERK signalling pathway. This study may provide therapeutic advances for the treatment and early diagnosis of patients with metastatic GC.

Hypoxic gastric cancer-derived exosomes promote progression and metastasis via MiR-301a-3p/PHD3/HIF-1α positive feedback loop

Hypoxic tumor microenvironment(TME) is a universal feature in solid carcinoma and is associated with unfavorable prognosis. Tumor-derived exosomes are now significantly implicating in mediating cellular communication and interactions in TME. The aim of this study was to identify exosomal miR-301a-3p involved in gastric cancer(GC) progression and metastasis. Here, we found hypoxia promote GC exosomes release and miR-301a-3p expression in an HIF-1α-dependent manner. In hypoxic TME, enriched miR-301a-3p could be transmitted between GC cells via exosomes and then contributed to inhibit HIF-1α degradation through targeting PHD3, that were capable to hydroxylate HIF-1α subunits to ubiquitinate degradation. This synergistical positive feedback loop between HIF-1α and miR-301a-3p facilitated GC proliferation, invasion, migration, and epithelial-mesenchymal transition. In clinical samples, we further discovered circulating exosomal miR-301a-3p in serum was positively related with peritoneal metastasis. Collectively, these data indicate that GC cells could generate miR-301a-3p-rich exosomes in the hypoxic TME, which then help to HIF-1α accumulation and promote GC malignant behaviors and metastasis. Exosomal miR-301a-3p/HIF-1α signaling axis may serve as a promising predictor and potential therapeutic target of GC with metastasis.