Although the tumor stroma in solid tumors like gastric cancer (GC) plays a crucial role in chemo-resistance, specific targets to inhibit the interaction between the stromal and cancer cells have not ...yet been utilized in clinical practice. The present study aims to determine whether cancer-associated fibroblasts (CAFs), a major component of the tumor stroma, confer chemotherapeutic resistance to GC cells, and to discover potential targets to improve chemo-response in GC.
To identify CAF-specific proteins and signal transduction pathways affecting chemo-resistance in GC cells, secretome and transcriptome analyses were performed. We evaluated the inhibiting effect of CAF-specific protein in in vivo and in vitro models and investigated the expression of CAF-specific protein in human GC tissues.
Secretome and transcriptome data revealed that interleukin-6 (IL-6) is a CAF-specific secretory protein that protects GC cells via paracrine signaling. Furthermore, CAF-induced activation of the Janus kinase 1-signal transducer and activator of transcription 3 signal transduction pathway confers chemo-resistance in GC cells. CAF-mediated inhibition of chemotherapy-induced apoptosis was abrogated by the anti-IL-6 receptor monoclonal antibody tocilizumab in various experimental models. Clinical data revealed that IL-6 was prominently expressed in the stromal portion of GC tissues, and IL-6 upregulation in GC tissues was correlated with poor responsiveness to chemotherapy.
Our data provide plausible evidence for crosstalk between GC cells and CAFs, wherein IL-6 is a key contributor to chemoresistance. These findings suggest the potential therapeutic application of IL-6 inhibitors to enhance the responsiveness to chemotherapy in GC.
Abstract
Textbook outcome is a composite quality measurement of short-term outcomes for evaluating complex surgical procedures. We compared textbook outcome and survival of robotic total gastrectomy ...(RTG) with those of laparoscopic total gastrectomy (LTG). We retrospectively reviewed 395 patients (RTG, n = 74; LTG, n = 321) who underwent curative total gastrectomy for gastric cancer via minimally invasive approaches from 2009 to 2018. We performed propensity score matched analysis to adjust for potential selection bias. Textbook outcome included a negative resection margin, no intraoperative complication, retrieved lymph nodes > 15, no severe complication, no reintervention, no unplanned intensive care unit admission, hospitalization ≤ 21 days, no readmission after discharge, and no postoperative mortality. Survival outcomes included 3-year overall and relapse-free survival rates. After matching, 74 patients in each group were selected. Textbook outcome was similar in the RTG and LTG groups (70.3% and 75.7%, respectively), although RTG required a longer operative time. The quality metric least often achieved was the presence of severe complications in both groups (77.0% in both groups). There were no differences in the 3-year overall survival rate (98.6% and 89.7%, respectively; log-rank P = 0.144) and relapse-free survival rate between the RTG and LTG groups (97.3% and 87.0%, respectively; log-rank P = 0.167). Textbook outcome and survival outcome of RTG were similar to those of LTG for gastric cancer.
It is unclear whether laparoscopic distal gastrectomy for locally advanced gastric cancer is oncologically equivalent to open distal gastrectomy. The noninferiority of laparoscopic subtotal ...gastrectomy with D2 lymphadenectomy for locally advanced gastric cancer compared with open surgery in terms of 3-year relapse-free survival rate was evaluated.
A phase III, open-label, randomized controlled trial was conducted for patients with histologically proven locally advanced gastric adenocarcinoma suitable for distal subtotal gastrectomy. The primary end point was the 3-year relapse-free survival rate; the upper limit of the hazard ratio (HR) for noninferiority was 1.43 between the laparoscopic and open distal gastrectomy groups.
From November 2011 to April 2015, 1,050 patients were randomly assigned to laparoscopy (n = 524) or open surgery (n = 526). After exclusions, 492 patients underwent laparoscopic surgery and 482 underwent open surgery and were included in the analysis. The laparoscopy group, compared with the open surgery group, suffered fewer early complications (15.7%
23.4%, respectively;
= .0027) and late complications (4.7%
9.5%, respectively;
= .0038), particularly intestinal obstruction (2.0%
4.4%, respectively;
= .0447). The 3-year relapse-free survival rate was 80.3% (95% CI, 76.0% to 85.0%) for the laparoscopy group and 81.3% (95% CI, 77.0% to 85.0%; log-rank
= .726) for the open group. Cox regression analysis after stratification by the surgeon revealed an HR of 1.035 (95% CI, 0.762 to 1.406; log-rank
= .827;
for noninferiority = .039). When stratified by pathologic stage, the HR was 1.020 (95% CI, 0.751 to 1.385; log-rank
= .900;
for noninferiority = .030).
Laparoscopic distal gastrectomy with D2 lymphadenectomy was comparable to open surgery in terms of relapse-free survival for patients with locally advanced gastric cancer. Laparoscopic distal gastrectomy with D2 lymphadenectomy could be a potential standard treatment option for locally advanced gastric cancer.
Histologic features of diffuse-type gastric cancer indicate that the tumor microenvironment (TME) may substantially impact tumor invasiveness. However, cellular components and molecular features ...associated with cancer invasiveness in the TME of diffuse-type gastric cancers are poorly understood.
We performed single-cell RNA-sequencing (scRNA-seq) using tissue samples from superficial and deep invasive layers of cancerous and paired normal tissues freshly harvested from five patients with diffuse-type gastric cancer. The scRNA-seq results were validated by immunohistochemistry (IHC) and duplex
hybridization (ISH) in formalin-fixed paraffin-embedded tissues.
Seven major cell types were identified. Fibroblasts, endothelial cells, and myeloid cells were categorized as being enriched in the deep layers. Cell type-specific clustering further revealed that the superficial-to-deep layer transition is associated with enrichment in inflammatory endothelial cells and fibroblasts with upregulated
transcripts. IHC and duplex ISH revealed the distribution of the major cell types and CCL2-expressing endothelial cells and fibroblasts, indicating tumor invasion. Elevation of CCL2 levels along the superficial-to-deep layer axis revealed the immunosuppressive immune cell subtypes that may contribute to tumor cell aggressiveness in the deep invasive layers of diffuse-type gastric cancer. The analyses of public datasets revealed the high-level coexpression of stromal cell-specific genes and that
correlated with poor survival outcomes in patients with gastric cancer.
This study reveals the spatial reprogramming of the TME that may underlie invasive tumor potential in diffuse-type gastric cancer. This TME profiling across tumor layers suggests new targets, such as CCL2, that can modify the TME to inhibit tumor progression in diffuse-type gastric cancer.
.
Background
The effects of cancer-associated fibroblasts (CAF) on the progression of gastric carcinoma (GC) has recently been demonstrated. However, agents targeting the interaction between CAF and GC ...cells have not been applied in a clinical setting. Here, we examined if inhibition for Axl receptor tyrosine kinase (AXL) can suppress CAF-induced aggressive phenotype in GC.
Methods
We investigated the function of CAF-derived growth arrest-specific 6 (GAS6), a major ligand of AXL, on the migration and proliferation of GC cells. The effect of the AXL inhibitor, BGB324, on the CAF-induced aggressive phenotype of GC cells was also investigated. In addition, we performed immunohistochemistry to examine the expression of phosphorylated AXL protein in 175 GC tissues and evaluated its correlation with the prognosis.
Results
The qPCR and western blot analysis showed that GAS6 expression was higher in CAF relative to other cells. We found that co-culture with CAF increased the phosphorylation of AXL (P-AXL), differentiation into a mesenchymal-like phenotype, and cell survival in GC cell lines. When the expression of
AXL
was genetically inhibited in GC cells, the effect of CAF was reduced. BGB324, a small molecule inhibitor of AXL, suppressed the effects of CAF on GC cell lines. In GC tissues, high levels of P-AXL were significantly associated with poor overall survival (
P
= 0.022).
Conclusions
We concluded that CAF are a major source of GAS6 and that GAS6 promotes an aggressiveness through AXL activation in GC. We suggested that an AXL inhibitor may be a novel agent for GC treatment.
Summary Background Chemotherapy is the standard of care for incurable advanced gastric cancer. Whether the addition of gastrectomy to chemotherapy improves survival for patients with advanced gastric ...cancer with a single non-curable factor remains controversial. We aimed to investigate the superiority of gastrectomy followed by chemotherapy versus chemotherapy alone with respect to overall survival in these patients. Methods We did an open-label, randomised, phase 3 trial at 44 centres or hospitals in Japan, South Korea, and Singapore. Patients aged 20–75 years with advanced gastric cancer with a single non-curable factor confined to either the liver (H1), peritoneum (P1), or para-aortic lymph nodes (16a1/b2) were randomly assigned (1:1) in each country to chemotherapy alone or gastrectomy followed by chemotherapy by a minimisation method with biased-coin assignment to balance the groups according to institution, clinical nodal status, and non-curable factor. Patients, treating physicians, and individuals who assessed outcomes and analysed data were not masked to treatment assignment. Chemotherapy consisted of oral S-1 80 mg/m2 per day on days 1–21 and cisplatin 60 mg/m2 on day 8 of every 5-week cycle. Gastrectomy was restricted to D1 lymphadenectomy without any resection of metastatic lesions. The primary endpoint was overall survival, analysed by intention to treat. This study is registered with UMIN-CTR, number UMIN000001012. Findings Between Feb 4, 2008, and Sept 17, 2013, 175 patients were randomly assigned to chemotherapy alone (86 patients) or gastrectomy followed by chemotherapy (89 patients). After the first interim analysis on Sept 14, 2013, the predictive probability of overall survival being significantly higher in the gastrectomy plus chemotherapy group than in the chemotherapy alone group at the final analysis was only 13·2%, so the study was closed on the basis of futility. Overall survival at 2 years for all randomly assigned patients was 31·7% (95% CI 21·7–42·2) for patients assigned to chemotherapy alone compared with 25·1% (16·2–34·9) for those assigned to gastrectomy plus chemotherapy. Median overall survival was 16·6 months (95% CI 13·7–19·8) for patients assigned to chemotherapy alone and 14·3 months (11·8–16·3) for those assigned to gastrectomy plus chemotherapy (hazard ratio 1·09, 95% CI 0·78–1·52; one-sided p=0·70). The incidence of the following grade 3 or 4 chemotherapy-associated adverse events was higher in patients assigned to gastrectomy plus chemotherapy than in those assigned to chemotherapy alone: leucopenia (14 patients 18% vs two 3%), anorexia (22 29% vs nine 12%), nausea (11 15% vs four 5%), and hyponatraemia (seven 9% vs four 5%). One treatment-related death occurred in a patient assigned to chemotherapy alone (sudden cardiopulmonary arrest of unknown cause during the second cycle of chemotherapy) and one occurred in a patient assigned to chemotherapy plus gastrectomy (rapid growth of peritoneal metastasis after discharge 12 days after surgery). Interpretation Since gastrectomy followed by chemotherapy did not show any survival benefit compared with chemotherapy alone in advanced gastric cancer with a single non-curable factor, gastrectomy cannot be justified for treatment of patients with these tumours. Funding The Ministry of Health, Labour and Welfare of Japan and the Korean Gastric Cancer Association.
We report proteogenomic analysis of diffuse gastric cancers (GCs) in young populations. Phosphoproteome data elucidated signaling pathways associated with somatic mutations based on ...mutation-phosphorylation correlations. Moreover, correlations between mRNA and protein abundances provided potential oncogenes and tumor suppressors associated with patient survival. Furthermore, integrated clustering of mRNA, protein, phosphorylation, and N-glycosylation data identified four subtypes of diffuse GCs. Distinguishing these subtypes was possible by proteomic data. Four subtypes were associated with proliferation, immune response, metabolism, and invasion, respectively; and associations of the subtypes with immune- and invasion-related pathways were identified mainly by phosphorylation and N-glycosylation data. Therefore, our proteogenomic analysis provides additional information beyond genomic analyses, which can improve understanding of cancer biology and patient stratification in diffuse GCs.
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•Mutation-phosphorylation correlation suggests possible signaling interplays in EOGCs•mRNA-protein correlation suggests genes with high association with patient survival•Integrated analysis of mRNA and protein data identified four subtypes•Phosphorylation data provide cellular signaling pathways underlying the subtypes
Mun et al. perform proteogenomic analysis of diffuse gastric cancers (DGC) in a young population, identifying that correlations of mRNA-protein abundance associate with survival and defining four subtypes of DGC. The associations of some subtypes with related pathways are identified mainly by the proteomic data.
Background
We aimed to evaluate the safety and efficacy of a clinical pathway (CP) for enhanced recovery after surgery (ERAS) in gastric cancer patients, including early oral feeding and discharge on ...postoperative day 4.
Methods
We performed a prospective, single‐center, phase II clinical trial. Based on proposed indications for an ERAS CP in our retrospective study, we enrolled 133 patients younger than 65 years who were undergoing minimally invasive subtotal gastrectomy. The primary endpoint was the ERAS CP completion rate. Secondary endpoints included complication, mortality, hospital stay, and readmission.
Results
Among 133 patients, six patients were dropped out from this study. The ERAS CP completion rate (77.2%, 98 of 127) was comparable to the historical control group that completed a conventional CP (85.4%, P = .085). The postoperative complication incidence (13.4%, 15 of 127) was also similar to that of the conventional CP group (9.5%, P = .174). We identified reduced hospital stays (4.7 ± 1.3 vs 7.2±2.3 days; P < .001) and lower hospital costs ($7771 vs 8539; P < .001) in the ERAS CP group compared with the conventional CP group.
Conclusions
An ERAS CP can be safely and effectively adopted for patients with gastric cancer without increasing the complication rate and could shorten hospital stays.
Trial Registration
ClinicalTrials.gov (NCT01642953).
Background
With improved short-term surgical outcomes, laparoscopic distal gastrectomy has rapidly gained popularity. However, the safety and feasibility of laparoscopic total gastrectomy (LTG) has ...not yet been proven due to the difficulty of the technique. This single-arm prospective multi-center study was conducted to evaluate the use of LTG for clinical stage I gastric cancer.
Methods
Between October 2012 and January 2014, 170 patients with pathologically proven, clinical stage I gastric adenocarcinoma located at the proximal stomach were enrolled. Twenty-two experienced surgeons from 19 institutions participated in this clinical trial. The primary end point was the incidence of postoperative morbidity and mortality at postoperative 30 days. The severity of postoperative complications was categorized according to Clavien–Dindo classification, and the incidence of postoperative morbidity and mortality was compared with that in a historical control.
Results
Of the enrolled patients, 160 met criteria for inclusion in the full analysis set. Postoperative morbidity and mortality rates reached 20.6% (33/160) and 0.6% (1/160), respectively. Fifteen patients (9.4%) had grade III or higher complications, and three reoperations (1.9%) were performed. The incidence of morbidity after LTG in this trial did not significantly differ from that reported in a previous study for open total gastrectomy (18%).
Conclusions
LTG performed by experienced surgeons showed acceptable postoperative morbidity and mortality for patients with clinical stage I gastric cancer.
To determine the safety of laparoscopy-assisted distal gastrectomy (LADG) compared with open distal gastrectomy (ODG) in patients with clinical stage I gastric cancer in Korea.
There is still a lack ...of large-scale, multicenter randomized trials regarding the safety of LADG.
A large-scale, phase 3, multicenter, prospective randomized controlled trial was conducted. The primary end point was 5-year overall survival. Morbidity within 30 postoperative days and surgical mortality were compared to evaluate the safety of LADG as a secondary end point
: A total of 1416 patients were randomly assigned to the LADG group (n = 705) or the ODG group (n = 711) between February 1, 2006, and August 31, 2010, and 1384 patients were analyzed for modified intention-to-treat analysis (ITT) and 1256 were eligible for per protocol (PP) analysis (644 and 612, respectively). In the PP analysis, 6 patients (0.9%) needed open conversion in the LADG group. The overall complication rate was significantly lower in the LADG group (LADG vs ODG; 13.0% vs 19.9%, P = 0.001). In detail, the wound complication rate of the LADG group was significantly lower than that of the ODG group (3.1% vs 7.7%, P < 0.001). The major intra-abdominal complication (7.6% vs 10.3%, P = 0.095) and mortality rates (0.6% vs 0.3%, P = 0.687) were similar between the 2 groups. Modified ITT analysis showed similar results with PP analysis.
LADG for patients with clinical stage I gastric cancer is safe and has a benefit of lower occurrence of wound complication compared with conventional ODG.
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