Surgical management of metastatic gastric cancer: moving beyond the guidelines

Top Peritoneal Surface Malignancy Articles from 2022 to Inform your Cancer Practice

Over the last few decades, the role of cytoreductive surgery (CRS) with or without regional-based peritoneal therapies such as hyperthermic intraperitoneal chemotherapy (HIPEC) has evolved in the management of patients with peritoneal surface malignances (PSMs). Despite the benefit of CRS in improving oncologic outcomes, significant challenges remain in the treatment of patients with advanced PSMs, and the role of HIPEC continues to be questioned. Additionally, while there has been improvement in perioperative outcomes, long-term survival remains poor. As a result, there is much need to improve our understanding of the processes that drive tumor biology, thereby improving patient selection for various treatment approaches. Additionally, newer therapies are needed for patients who remain poor surgical candidates and who progress on systemic therapy. This article highlights recently published studies that we consider impactful in the care of patients with PSMs.

G-protein-coupled estrogen receptor 1 promotes peritoneal metastasis of gastric cancer through nicotinamide adenine dinucleotide kinase 1-mediated redox modulation

Adipose tissue is the second most important site of estrogen production, where androgens are converted into estrogen by aromatase. While gastric cancer patients often develop adipocyte-rich peritoneal metastasis, the underlying mechanism remains unclear. In this study, we identified the G-protein-coupled estrogen receptor (GPER1) as a promoter of gastric cancer peritoneal metastasis. Functional in vitro studies revealed that β-Estradiol (E2) or the GPER1 agonist G1 inhibited anoikis in gastric cancer cells. Additionally, genetic overexpression or knockout of GPER1 significantly inhibited or enhanced gastric cancer cell anoikis in vitro and peritoneal metastasis in vivo, respectively. Mechanically, GPER1 knockout disrupted the NADPH pool and increased reactive oxygen species (ROS) generation. Conversely, overexpression of GPER1 had the opposite effects. GPER1 suppressed nicotinamide adenine dinucleotide kinase 1(NADK1) ubiquitination and promoted its phosphorylation, which were responsible for the elevated expression of NADK1 at protein levels and activity, respectively. Moreover, genetic inhibition of NADK1 disrupted NADPH and redox homeostasis, leading to high levels of ROS and significant anoikis, which inhibited lung and peritoneal metastasis in cell-based xenograft models. In summary, our study suggests that inhibiting GPER1-mediated NADK1 activity and its ubiquitination may be a promising therapeutic strategy for peritoneal metastasis of gastric cancer.

LncRNA-CCAT5-mediated crosstalk between Wnt/β-Catenin and STAT3 signaling suggests novel therapeutic approaches for metastatic gastric cancer with high Wnt activity

BACKGROUND

Although the constitutively activated Wnt/β-catenin signaling pathway plays vital roles in gastric cancer (GC) progression, few Wnt inhibitors are approved for clinical use. Additionally, the clinical significance of long non-coding RNAs (lncRNAs) in GC intraperitoneal dissemination (IPD) remains elusive. Here, we investigated the function and therapeutic potential of Wnt-transactivated lncRNA, colon cancer-associated transcript 5 (CCAT5), in GC metastasis.

METHODS

LncRNA-sequencing assay was performed to document abundance changes of lncRNAs induced by Wnt family member 3A (Wnt3a) and degradation-resistant β-catenin (S33Y mutated) in ascites-derived GC cells with low Wnt activity. Luciferase reporter, Chromatin immunoprecipitation (ChIP)-re-ChIP assays were performed to determine how CCAT5 was transcribed. The clinical significance of CCAT5 was examined in 2 cohorts of GC patients. The biological function of CCAT5 was investigated through gain- and loss-of-function studies. The molecular mechanism was explored through RNA-sequencing, mass spectrometry, and CRISPR/Cas9-knocknout system. The therapeutic potential of CCAT5 was examined through RNAi-based cell xenograft model and patient-derived xenograft (PDX) model of IPD.

RESULTS

We identified a novel Wnt-regulated lncRNA, CCAT5, which was transactivated by the β-catenin/transcription factor 3 (TCF3) complex. CCAT5 was significantly upregulated in GC and predicted poor prognosis. Functional studies confirmed the promotive role of CCAT5 in GC growth and metastasis. Mechanistically, CCAT5 bound to the C-end domain of signal transducer and activator of transcription 3 (STAT3) and blocks Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP-1)-mediated STAT3Y705 dephosphorylation, leading to STAT3 nuclear entry and transactivation, thus accelerating GC progression. Furthermore, we demonstrated that both Wnt3a and β-catenin acted as activator of STAT3 signaling pathway, and the interplay between CCAT5 and STAT3 was functionally essential for Wnt-drived STAT3 signaling and tumor evolution. Finally, we revealed in vivo si-CCAT5 selectively attenuated growth and metastasis of Wnthigh GC, but not Wntlow GC. The combination of si-CCAT5 and oxaliplatin displayed obvious synergistic therapeutic effects on Wnthigh PDX mice.

CONCLUSIONS

We identified a novel Wnt-transactivated lncRNA, CCAT5. Our study revealed a mechanism of STAT3 signaling regulation via canonical Wnt signaling and the functional significance of CCAT5 as critical mediator. We provided conceptual advance that lncRNAs serve as therapeutic targets reversing GC progression.

Surgery for locally advanced gastric cancer in the era of neoadjuvant therapies: something new?

BACKGROUND

Locally advanced gastric cancer (LAGC) represents a therapeutic challenge, particularly as it often involves adjacent organs. The necessity of neoadjuvant treatments for LAGC patients is still controversial. The aim of this study was to analyze the factors affecting prognosis and survival in patients with LAGC with particular regard to the effect of neoadjuvant therapies.

METHODS

Between January 2005 and December 2018, the medical records of 113 patients with LAGC who underwent curative resection were retrospectively reviewed. Patient characteristics, related complications, long-term survival, and prognostic factors were analyzed at uni- and multivariate analyses.

RESULTS

Postoperative mortality and morbidity rates of patients undergoing neo-adjuvant therapies were 2.3% and 43.2%, respectively. Whereas in patients undergoing upfront surgery were 4.6% and 26.1%, respectively. R0 resection was achieved 79.5% and in 73.9% of patients undergoing neoadjuvant therapy and upfront surgery, respectively (P<0.001). Multivariate analysis revealed that neoadjuvant therapy, completeness of resection (R0), number of lymph nodes retrieved, N status and the adoption of hyperthermic intraperitoneal chemotherapy were independent prognostic factors associated with longer survival. Five-year overall survival for NAC group and upfront surgery group was 46% and 32%, respectively (P=0.04). Five-year disease-free survival for NAC group and upfront surgery group was 38% and 25%, respectively (P=0.02).

CONCLUSIONS

Patients with LAGC undergoing surgery plus neoadjuvant therapy had a better OS and DFS with respect to patients treated with surgery alone.

Long-term survival after multidisciplinary treatments for HER2-positive advanced gastric cancer with multiple liver and lung metastases

BACKGROUND

Trastuzumab-based chemotherapy is a standard treatment regimen for human epithelial growth factor 2 (HER2)-positive gastric cancer. This is a case of a patient who has survived 12 years after being diagnosed with advanced gastric cancer with multiple liver and lung metastases.

CASE PRESENTATION

A woman in her 70s underwent total gastrectomy, cholecystectomy, and left hepatic lobectomy for gastric cancer with liver metastasis. One month after the surgery, multiple liver metastases appeared. After two courses of S-1 + CDDP chemotherapy, the liver metastases disappeared, and new lung metastases occurred. Because the primary tumor was HER2 positive, S-1 + CDDP + trastuzumab chemotherapy was performed. After one course of chemotherapy, the blood test showed pancytopenia, and CDDP was discontinued. S-1 + trastuzumab chemotherapy was then initiated, and as a result, the lung metastases disappeared. The patient is alive without recurrence 12 years after the surgery.

CONCLUSIONS

We encountered a case of long-term survival after multidisciplinary treatments for HER2-positive advanced gastric cancer with multiple liver and lung metastases.

Gastrectomy with or without Complete Omentectomy for Advanced Gastric Cancer: A Meta-Analysis

Background and Objectives: Surgery remains the only possible curative treatment for advanced gastric cancer (AGC). Peritoneal metastases are estimated to occur in approximately 55–60% AGC patients. Greater omentum is the most common metastatic area in AGC. At present, omentectomy alone or bursectomy are usually carried out during gastric cancer surgery. We performed a meta-analysis in order to evaluate long-term and short-term outcomes among AGC patients, who have undergone radical gastrectomy with or without complete omentectomy (CO). Materials and Methods: We performed a systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Meta-analysis was performed by use of RevMan (Computer program) Version 5.4. Results: The eight included studies covered an approximately 20 years long study period (2000–2018). Almost all included studies were retrospective ones and originated from Asian countries. Meta-analysis indicated gastrectomy without CO as significantly associated with longer 3-year (RR: 0.94, 95% CI: 0.90–0.98, p = 0.005) and 5-year overall survivals (OS) (RR: 0.93, 95% CI: 0.88–0.98, p = 0.007). Moreover, we found longer operative time (MD: 24.00, 95% CI: −0.45–48.45, p = 0.05) and higher estimated blood loss (MD: 194.76, 95% CI: 96.40–293.13, p = 0.0001) in CO group. Conclusions: Non-complete omentectomy (NCO) group had a statistically greater rate in 3-year and 5-year OSs than the CO group, while the CO group had significantly longer operative time and higher estimated blood loss than the NCO group. Further randomized, possibly multi-center trials may turn out of paramount importance in confirming our results.

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

BACKGROUND

The multidisciplinary treatment including induction chemotherapy plus conversion surgery (CS) has attracted attention as a new strategy to improve the outcome of metastatic gastric cancer (MGC). However, it is unclear which patients achieve a good response to chemotherapy and successful CS. Tumor-infiltrating immune cells (TIICs) have been reported to be both prognostic and predictive biomarkers not only in immunotherapy but also in chemotherapy in many cancer types. However, there have been no reports on the usefulness of TIICs as biomarkers in conversion surgery for MGC. The aim of the present study was to evaluate the association between the TIICs and treatment outcome for the multidisciplinary treatment in MGC.

METHODS

We retrospectively analyzed 68 MGC patients who received docetaxel plus cisplatin plus S-1 (DCS) therapy between April 2006 and March 2019 in our institute. The number of tumor-infiltrating CD4+, CD8+, Foxp3+lymphocytes, CD68+, CD163+macrophages in pre-treatment endoscopic biopsy samples were evaluated to investigate their predictive value for multidisciplinary treatment.

RESULTS

Fifty patients underwent CS following DCS therapy (CS group), whereas 18 patients underwent DCS therapy alone (non-CS group). The median survival time (MST) of CS group was 33.3 months, which was significantly longer than the MST of 9.0 months in non-CS group (p < 0.01). The number of CD163+macrophages was extracted as an independent prognostic factor for overall survival in all patients. There were more cases of high infiltration of CD163+macrophages in non-CS group than in CS group. Furthermore, in CS group, pathological responders to DCS therapy showed low infiltration of CD163+ macrophages, and high infiltration of CD8+lymphocyte. CD163 low group showed a significant prolonged survival compared with CD163 high group in patients who underwent CS (p = 0.02).

CONCLUSIONS

The pre-treatment CD163+macrophages infiltration would be a pivotal biomarker for predicting prognosis and pathological response to multidisciplinary treatment among TIICs in MGC. Thus, for patients with low CD163+macrophage infiltration in pre-treatment biopsy sample, diagnostic imaging should be performed frequently during chemotherapy to avoid missing the optimal timing for CS, and CS should be aggressively considered as a treatment option if curative resection is deemed feasible.

Development of the PERI-Gastric (PEritoneal Recurrence Index) and PERI-Gram (Peritoneal Recurrence Index NomoGRAM) for predicting the risk of metachronous peritoneal carcinomatosis after gastrectomy with curative intent for gastric cancer

BACKGROUND

A model that quantifies the risk of peritoneal recurrence would be a useful tool for improving decision-making in patients undergoing curative-aim gastrectomy for gastric cancer (GC).

METHODS

Five Italian centers participated in this study. Two risk scores were created according to the two most widely used pathologic classifications of GC (the Lauren classification and the presence of signet-ring-cell features). The risk scores (the PERI-Gastric 1 and 2) were based on the results of multivariable logistic regressions and presented as nomograms (the PERI-Gram 1 and 2). Discrimination was assessed with the area under the curve (AUC) of receiver operating curves. Calibration graphs were constructed by plotting the actual versus the predicted rate of peritoneal recurrence. Internal validation was performed with a bootstrap resampling method (1000 iterations).

RESULTS

The models were developed based on a population of 645 patients (selected from 1580 patients treated from 1998 to 2018). In the PERI-Gastric 1, significant variables were linitis plastica, stump GC, pT3-4, pN2-3 and the Lauren diffuse histotype, while in the PERI-Gastric 2, significant variables were linitis plastica, stump GC, pT3-4, pN2-3 and the presence of signet-ring cells. The AUC was 0,828 (0.778-0.877) for the PERI-Gastric 1 and 0,805 (0.755-0.855) for the PERI-Gastric 2. After bootstrap resampling, the PERI-Gastric 1 had a mean AUC of 0.775 (0.721-0.830) and a 95%CI estimate for the calibration slope of 0.852-1.505 and the PERI-Gastric 2 a mean AUC of 0.749 (0.693-0.805) and a 95%CI estimate for the slope of 0.777-1.351. The models are available at www.perigastric.org .

CONCLUSIONS

We developed the PERI-Gastric and the PERI-Gram as instruments to determine the risk of peritoneal recurrence after curative-aim gastrectomy. These models could direct the administration of prophylactic intraperitoneal treatments.

Identifying Optimal Surgical Intervention-Based Chemotherapy for Gastric Cancer Patients With Liver Metastases

Background

This study aimed at evaluating the effects of surgical treatments-based chemotherapy in the treatment of gastric cancer with liver metastases (GCLM). It has not been established whether Liver-directed treatment (LDT) options such as hepatectomy and gastrectomy plus chemotherapy (HGCT), radiofrequency ablation and gastrectomy plus chemotherapy (RFAG), transarterial chemoembolization and gastrectomy plus chemotherapy (TACEG), gastrectomy plus chemotherapy (GCT) enhance the survival of GCLM patients.

Methods

We performed systematic literature searches in PubMed, EMBASE, and Cochrane library from inception to September 2021. We created a network plot to comprehensively analyze the direct and indirect evidence, based on a frequentist method. A contribution plot was used to determine inconsistencies, a forest plot was used to evaluate therapeutic effects, the publication bias was controlled by funnel plot, while the value of surface under the cumulative ranking curves (SUCRA) was calculated to estimate rank probability.

Results

A total of 23 retrospective studies were identified, involving 5472 GCLM patients. For OS and 1-, 2-, 3-year survival rate of all trials, meta-analysis of the direct comparisons showed significant better for HGCT treatments compared with GCT or PCT. In the comparison of the 5 treatments for 1-, 2-, 3-year survival rate, HGCT and RFAG were found to be more effective than GCT and PCT, respectively. By OS and 2-, 3-year survival rate analysis, RFAG was identified as the best option, followed by HGCT, TACEG, GCT and PCT. By 1-year survival rate analysis, HGCT and RFAG were identified as the most effective options.

Conclusion

HGCT and RFAG has remarkable survival benefits for GCLM patients when compared to TACEG, GCT and PCT. HGCT was found to exhibit superior therapeutic effects for GCLM patients for 1-year survival rate while RFAG was found to be a prospective therapeutic alternative for OS and 2-, 3-year survival rate.

Systematic Review Registration

identifier [10.37766/inplasy2020.12.0009].

Lemur tyrosine kinase 2 silencing inhibits the proliferation of gastric cancer cells by regulating GSK-3β phosphorylation and β-catenin nuclear translocation

Previous studies on the mechanism of proliferation and cell cycle progression of gastric cancer cells have shown promising perspectives for the prevention and treatment of gastric cancer. The aim of the present study was to investigate the role of lemur tyrosine kinase 2 (LMTK2) in gastric cancer cell proliferation and cell cycle progression, as well as in tumor-bearing nude mouse models. The expression levels of LMTK2 were determined in gastric cancer cell lines. In addition, the effects of LMTK2 silencing or overexpression on cell proliferation were measured using Cell Counting Kit-8, BrdU and colony formation assays. Cell cycle progression was analyzed using flow cytometry and western blotting. The expression levels of proteins associated with the β-catenin pathway were assessed using western blot analysis. A tumor-bearing nude mouse model was established by injecting gastric cancer cells, and the effect of LMTK2 knockdown or overexpression on tumor growth was examined. The expression levels of LMTK2 were found to be upregulated in all gastric cancer cell lines. Moreover, LMTK2 knockdown inhibited cell proliferation, colony formation and cell cycle progression. LMTK2 knockdown also inhibited the activation of GSK-3β/β-catenin signaling, as evidenced by reduced GSK-3β phosphorylation and nuclear β-catenin levels. LMTK2 knockdown also suppressed tumor growth, whereas overexpression accelerated this process. In conclusion, LMTK2 silencing can inhibit the proliferation of gastric cancer cells in vitro and tumor growth in vivo by regulating GSK-3β phosphorylation and β-catenin nuclear translocation.

Utility of 211At-Trastuzumab for the Treatment of Metastatic Gastric Cancer in the Liver: Evaluation of a Preclinical α-Radioimmunotherapy Approach in a Clinically Relevant Mouse Model

A liver metastasis from a primary gastric cancer (LMGC) is relatively common and results in an extremely poor prognosis due to a lack of effective therapeutics. We here demonstrate in a clinically relevant mouse model that an α-particle radioimmunotherapy approach with 211At-labeled trastuzumab has efficacy against LMGCs that are positive for human epidermal growth factor receptor 2 (HER2). Methods:211At was produced in a cyclotron via a 209Bi (α,2n) 211At reaction. 211At-trastuzumab was subsequently generated using a single-step labeling method. NCI-N87 cells (HER2-positive human gastric cancer cells) carrying a luciferase gene were intrasplenically transplanted into severe combined immunodeficiency mice to generate an HER2-positive LMGC model. A biodistribution study was then conducted through the intravenous injection of 211At-trastuzumab (1 MBq) into these LMGC xenograft mice. In parallel with this experimental therapy, phosphate-buffered saline, intact trastuzumab, or 211At-nonspecific human IgG (1 MBq) was injected into control groups. The therapeutic efficacy was evaluated by monitoring tumor changes by chemiluminescence imaging. Body weights, white blood cell counts, and serum markers of tissue damage were monitored at regular intervals. Microdosimetry using a CR-39 plastic detector was also performed. Results: The biodistribution analysis revealed an increased uptake of 211At-trastuzumab in the metastasized tumors that reached approximately 12% of the injected dose per gram of tissue (%ID/g) at 24 h. In contrast, its uptake to the surrounding liver was about 4 %ID/g. The LMGCs in the mouse model reduced dramatically at 1 wk after the single systemic injection of 211At-trastuzumab. No recurrences were observed in 6 of 8 mice treated with this single injection, and their survival time was significantly prolonged compared with the control groups, including the animals treated with 211At-nonspecific antibodies. No severe toxicities or abnormalities in terms of body weight, white blood cell number, liver function, or kidney parameters were observed in the 211At-trastuzumab group. Microdosimetric studies further revealed that 211At-trastuzumab had been delivered at an 11.5-fold higher dose to the LMGC lesions than to the normal liver. Conclusion: α-radioimmunotherapy with 211At-trastuzumab has considerable potential as an effective and safe therapeutic option for LMGC.

Advances in the surgical management of gastric and gastroesophageal junction cancer

Since Theodore Billroth and Cesar Roux perfected the methods of post-gastrectomy reconstruction in the late 19^th century, surgical management of gastric and gastroesophageal cancer has made incremental progress. The majority of patients with localized disease are treated with perioperative combination chemotherapy or neoadjuvant chemoradiation. Staging laparoscopy before initiation of treatment or before surgical resection has improved staging accuracy and can drastically inform treatment decisions. The longstanding and contentious debate on the optimal extent of lymph node dissection for gastric cancer appears to have settled in favor of D2 dissection with the recently published 15-year follow-up of the Dutch randomized trial. Minimally invasive gastric and gastroesophageal resections are performed routinely in most centers affording faster recovery and equivalent oncologic outcomes. Pylorus-preserving distal (central) gastrectomy has emerged as a less invasive, function-preserving option for T1N0 middle-third gastric cancers, while randomized data on its oncologic adequacy are pending. Multi-visceral resections and cytoreductive surgery with hyperthermic intraperitoneal chemotherapy has been utilized selectively for patients with locally advanced tumors who have demonstrated disease control on preoperative chemotherapy. This review summarizes the current standard of surgical care for gastroesophageal junction and gastric cancer as well as highlights recent and upcoming advances to the field.

Nomogram for Predicting Survival in Advanced Gastric Cancer after Neoadjuvant Chemotherapy and Radical Surgery

BACKGROUND

Neoadjuvant chemotherapy (NAC) with subsequent radical surgery has become a popular treatment modality for advanced gastric cancer (AGC) worldwide. However, the survival benefit is still controversial, and prognostic factors remain undetermined.

AIM

To identify clinical parameters that are associated with the survival of AGC patients after NAC and radical surgery and to establish a nomogram integrating multiple factors to predict survival.

METHODS

We reviewed the medical profiles of 215 AGC patients who received NAC and radical resection, and clinical parameters concerning NAC, surgery, pathological findings, and adjuvant chemotherapy were analyzed using a Cox regression model to determine their impact on survival. Based on these factors, a nomogram was developed and validated.

RESULTS

The overall 1-year and 3-year survival rates were 85.8% and 55.6%, respectively. Younger age (<60 years old), increased examined lymph nodes (exLNs), successful R0 resection, the achievement of pathological complete response (pCR), and acceptance of adjuvant chemotherapy were positive predictors of survival. The C-index of the established nomogram was 0.785. The area under receiver operating curve (ROC) at 1/3 years of prediction was 0.694/0.736, respectively. The model showed an ideal calibration following internal bootstrap validation.

CONCLUSION

A nomogram predicting survival after NAC and surgery was established. Since this nomogram exhibited satisfactory and stable predictive power, it can be inferred that this is a practical tool for predicting AGC patient survival after NAC and radical surgery.

Prognostic Value of the Site of Distant Metastasis and Surgical Interventions in Metastatic Gastric Cancer: A Population-Based Study

BACKGROUND

Studies on the prognostic significance of site-specific distant metastasis, multiple-site metastases, and the impact of surgery of the primary tumor and metastatic lesion on survival outcomes of patients with metastatic gastric cancer (GC) remain elusive. Therefore, this study aimed to investigate the prognostic significance of the site of distant metastasis among patients with metastatic GC. Furthermore, the effect of surgery of the primary tumor and metastatic lesion on the prognosis of metastatic GC was also analyzed.

METHODS

The data of 4,221 eligible patients, who were diagnosed with metastatic GC between 2010 and 2015, were identified from the Surveillance Epidemiology and End Results (SEER) database. Multivariate logistic regression analysis was performed to assess the association between potential prognostic factors, including the site of metastasis and surgery, and survival of patients with metastatic GC. Overall survival (OS) and cause-specific survival (CSS) were determined using the Kaplan-Meier survival curves and differences were assessed using the Log-rank test.

RESULTS

Out of the total 4,221 GC patients with definite organ metastases, 3312 patients had single-site metastasis while 909 patients had multiple-site metastases. GC patients with single-site metastasis of liver or lung exhibited better CSS and OS compared to those with bone metastasis. Furthermore, GC patients with liver metastasis benefited from surgery of both the primary and metastatic lesions, while those with lung metastasis benefited from surgery of metastasis resection only. Multivariate Cox regression analysis revealed that GC patients with single-site metastasis, well-differentiated tumors, GC patients who underwent surgery of the primary tumor and those who received chemotherapy exhibited favorable prognosis.

CONCLUSIONS

The site of metastasis was an independent prognostic factor for metastatic GC. Surgery had survival benefits in certain cases of metastatic GC; however, further studies are warranted to clarify these benefits in carefully selected patients.

CLDN4 silencing promotes proliferation and reduces chemotherapy sensitivity of gastric cancer cells through activation of the PI3K/Akt signalling pathway

NEW FINDINGS

What is the central question of this study? What is the influence of the interaction between the matrix protein CLDN4 and the PI3K/Akt signalling pathway on tumour progression and chemotherapy sensitivity in gastric cancer? What is the main finding and its importance? Silencing of CLDN4 can promote the growth and proliferation of gastric cancer cells by activating the PI3K/Akt signalling pathway, and thus reduce the sensitivity of gastric cancer cells to chemotherapy.

ABSTRACT

Gastric cancer (GC) is one of the most common cancers worldwide and has a high mortality rate, accompanied by metastasis. Claudins (CLDNs) are major tight-junction proteins that mediate cellular polarity and differentiation. In the present study, we investigated the role of claudin 4 (CLDN4) in modulating cell proliferation and chemotherapeutic sensitivity in GC. Immunohistochemistry and RT-qPCR were initially used to detect the expression of CLDN4 in cancer tissues and adjacent normal tissues collected from GC patients. GC cell lines with the highest and the lowest CLDN4 expression were selected for subsequent experiments. The effects of CLDN4 on GC cell chemosensitivity, proliferation, invasion, migration, apoptosis and tumourigenic capacity were evaluated by conducting gain- and loss-of-function studies of CLDN4. Expression of CLDN4 was significantly decreased in GC tissues and cell lines compared to adjacent normal tissues or gastric epithelial cells. Silencing of CLDN4 increased the extent of PI3K and Akt phosphorylation, and also the proliferation, migration, invasion and tumourigenesis of GC cells; at the same time apoptosis and the sensitivity of GC cells to chemotherapy were reduced. In conclusion, CLDN4 may play a pivotal role in attenuating GC cell proliferation and enhancing sensitivity of GC cells to chemotherapy by inactivating the PI3K/Akt signalling pathway.

Targeting Wnt Signaling for the Treatment of Gastric Cancer

The Wnt signaling pathway is evolutionarily conserved, regulating both embryonic development and maintaining adult tissue homeostasis. Wnt signaling controls several fundamental cell functions, including proliferation, differentiation, migration, and stemness. It therefore plays an important role in the epithelial homeostasis and regeneration of the gastrointestinal tract. Often, both hypo- or hyper-activation of the pathway due to genetic, epigenetic, or receptor/ligand alterations are seen in many solid cancers, such as breast, colorectal, gastric, and prostate. Gastric cancer (GC) is the fourth commonest cause of cancer worldwide and is the second leading cause of cancer-related death annually. Although the number of new diagnoses has declined over recent decades, prognosis remains poor, with only 15% surviving to five years. Geographical differences in clinicopathological features are also apparent, with epidemiological and genetic studies revealing GC to be a highly heterogeneous disease with phenotypic diversity as a result of etiological factors. The molecular heterogeneity associated with GC dictates that a single 'one size fits all' approach to management is unlikely to be successful. Wnt pathway dysregulation has been observed in approximately 50% of GC tumors and may offer a novel therapeutic target for patients who would otherwise have a poor outcome. This mini review will highlight some recent discoveries involving Wnt signaling in GC.

Spontaneous acute epidural hematoma associated with chronic subdural hematoma due to dural metastasis of gastric carcinoma: a case report and literature review

Background: Non-traumatic spontaneous acute epidural hematoma (EDH) happening to chronic subdural hematoma (SDH) caused by dural metastases is a rare entity. Pathogenesis can be derived from infection, coagulopathy, and inflammation. Malignant tumors metastasize to dura mater is one of the most infrequent causes. The exact mechanism remains elusive in spite of several possible speculations. The clinical manifestations, management and outcomes vary among reported cases.Case Description: A 45-year-old woman without history of trauma presented with headache, vomiting and disturbance of consciousness and developed brain hernia rapidly. On arival, she has lost into coma with Glasgow coma scale (GCS) score 5, bilateral pupils were not equal, with disappeared reflectance. Emergency imaging prompted large acute EDH, combined with SDH, arising from dural granular neoplasm confirmed intraoperatively. Four days after surgery, the bilateral pupils were equal in size and sensitive to light reflection.Conclusion: Dural metastases can cause EDH, chronic SDH can also be resulted from metastatic tumors of dura mater. When dealing with spontaneous non-traumatic hematoma around the dura mater, to make the precise diagnosis is sometimes doubtful and confusing. The stream of diagnostic thinking should be opened, including medical diseases such as liver and kidney disease, drug history, history of cancer and other possible clues. Thus, a detailed and purposeful systematic medical history review and physical examination is important in order to make more appropriate strategies for the clinic.

Retrospective imaging studies of gastric cancer: Study protocol clinical trial (SPIRIT Compliant)

INTRODUCTION

Peritoneal metastasis (PM) is a frequent condition in patients presenting with gastric cancer, especially in younger patients with advanced tumor stages. Computer tomography (CT) is the most common noninvasive modality for preoperative staging in gastric cancer. However, the challenges of limited CT soft tissue contrast result in poor CT depiction of small peritoneal tumors. The sensitivity for detecting PM remains low. About 16% of PM are undetected. Deep learning belongs to the category of artificial intelligence and has demonstrated amazing results in medical image analyses. So far, there has been no deep learning study based on CT images for the diagnosis of PM in gastric cancer.

WE PROPOSED A HYPOTHESIS

CT images in the primary tumor region of gastric cancer had valuable information that could predict occult PM of gastric cancer, which could be extracted effectively through deep learning.

OBJECTIVE

To develop a deep learning model for accurate preoperative diagnosis of PM in gastric cancer.

METHOD

All patients with gastric cancer were retrospectively enrolled. All patients were initially diagnosed as PM negative by CT and later confirmed as positive through surgery or laparoscopy. The dataset was randomly split into training cohort (70% of all patients) and testing cohort (30% of all patients). To develop deep convolutional neural network (DCNN) models with high generalizability, 5-fold cross-validation and model ensemble were utilized. The area under the receiver operating characteristic curve, sensitivity and specificity were used to evaluate DCNN models on the testing cohort.

DISCUSSION

This study will help us know whether deep learning can improve the performance of CT in diagnosing PM in gastric cancer.

Deep Convolutional Neural Network Based on Computed Tomography Images for the Preoperative Diagnosis of Occult Peritoneal Metastasis in Advanced Gastric Cancer

We aimed to develop a deep convolutional neural network (DCNN) model based on computed tomography (CT) images for the preoperative diagnosis of occult peritoneal metastasis (OPM) in advanced gastric cancer (AGC). A total of 544 patients with AGC were retrospectively enrolled. Seventy-nine patients were confirmed with OPM during surgery or laparoscopy. CT images collected during the initial visit were randomly split into a training cohort and a testing cohort for DCNN model development and performance evaluation, respectively. A conventional clinical model using multivariable logistic regression was also developed to estimate the pretest probability of OPM in patients with gastric cancer. The DCNN model showed an AUC of 0.900 (95% CI: 0.851-0.953), outperforming the conventional clinical model (AUC = 0.670, 95% CI: 0.615-0.739; p < 0.001). The proposed DCNN model demonstrated the diagnostic detection of occult PM, with a sensitivity of 81.0% and specificity of 87.5% using the cutoff value according to the Youden index. Our study shows that the proposed deep learning algorithm, developed with CT images, may be used as an effective tool to preoperatively diagnose OPM in AGC.