Hyperactivation of mTOR/eIF4E Signaling Pathway Promotes the Production of Tryptophan-To-Phenylalanine Substitutants in EBV-Positive Gastric Cancer.

Although messenger RNA translation is tightly regulated to preserve protein synthesis and cellular homeostasis, chronic exposure to interferon-γ (IFN-γ) in several cancers can lead to tryptophan (Trp) shortage via the indoleamine-2,3-dioxygenase (IDO)- kynurenine pathway and therefore promotes the production of aberrant peptides by ribosomal frameshifting and tryptophan-to-phenylalanine (W>F) codon reassignment events (substitutants) specifically at Trp codons. However, the effect of Trp depletion on the generation of aberrant peptides by ribosomal mistranslation in gastric cancer (GC) is still obscure. Here, it is shows that the abundant infiltrating lymphocytes in EBV-positive GC continuously secreted IFN-γ, upregulated IDO1 expression, leading to Trp shortage and the induction of W>F substitutants. Intriguingly, the production of W>F substitutants in EBV-positive GC is linked to antigen presentation and the activation of the mTOR/eIF4E signaling pathway. Inhibiting either the mTOR/eIF4E pathway or EIF4E expression counteracted the production and antigen presentation of W>F substitutants. Thus, the mTOR/eIF4E pathway exposed the vulnerability of gastric cancer by accelerating the production of aberrant peptides and boosting immune activation through W>F substitutant events. This work proposes that EBV-positive GC patients with mTOR/eIF4E hyperactivation may benefit from anti-tumor immunotherapy.

Anti-Helicobacter pylori Treatment in Patients With Gastric Cancer After Radical Gastrectomy.

Importance: Whether anti-Helicobacter pylori treatment can provide survival benefits for patients with gastric cancer who are diagnosed with H pylori infection is an area with limited research. Objective: To explore the potential survival benefits of anti-H pylori treatment after radical gastrectomy in patients with gastric cancer and presurgical confirmation of H pylori infection. Design, Setting, and Participants: This retrospective cohort study was conducted using data from patients with gastric cancer treated between January 1, 2010, and December 31, 2018, and followed up for outcome ascertainment until May 19, 2021. Propensity score matching was performed in patients treated with or without anti-H pylori treatment. This study involved a single institute in a comprehensive cancer treatment and research center located in Guangzhou, Guangdong Province, China. The study included patients with gastric or esophagogastric junction adenocarcinoma who underwent curative gastrectomy with D2 lymphadenectomy and tested positive for H pylori infection. Data were analyzed from March to June 2023. Exposure: Anti-H pylori treatment, which primarily includes triple therapy regimens consisting of amoxicillin, clarithromycin, and omeprazole for 14 days. Main Outcomes and Measures: Clinical outcomes, including overall survival (OS) and disease-free survival (DFS), were analyzed by Kaplan-Meier method, log-rank test, and Cox proportional hazards regression model. Subgroup analysis based on crucial clinical information was also conducted. Results: All 1293 patients (median [IQR] age, 59 [50-65] years; 860 [66.5%] male) were divided into 2 groups, with 125 patients in the anti-H pylori treatment group and 1168 patients in the non-anti-H pylori treatment group based on whether they received anti-H pylori treatment during the perioperative period and the follow-up. Survival analysis showed that the 5-year OS rates were 94.1% (95% CI, 89.3%-99.2%) in the anti-H pylori group and 73.8% (95% CI, 70.7%-77.0%) in the non-anti-H pylori group, and the hazard ratio (HR) of these 2 groups was 0.33 (95% CI, 0.18-0.60; P < .001). The survival benefit remained after propensity score matching (HR, 0.50; 95% CI, 0.26-0.99; P = .048). Multivariable analysis for OS and DFS further showed the survival benefit of anti-H pylori treatment, with HRs of 0.38 (95% CI, 0.17-0.87; P = .02) and 0.48 (95% CI, 0.28-0.83; P = .008), respectively. Among patients with TNM stage II/III disease who received adjuvant chemotherapy, anti-H pylori treatment was associated with survival benefits (OS: HR, 0.49; 95% CI, 0.24-0.99; P = .046), whereas among those who did not receive adjuvant chemotherapy, anti-H pylori treatment was not associated with survival benefits (OS: HR, 0.29; 95% CI, 0.04-2.08; P = .22). Conclusions and Relevance: This cohort study indicates that anti-H pylori treatment may be associated with improved survival in patients with gastric cancer who have H pylori infections. The study reinforces the importance of including H pylori screening and treatment in the surgical treatment of these patients.

The role of computed tomography features in assessing response to neoadjuvant chemotherapy in locally advanced gastric cancer.

OBJECTIVE: To compare the computed tomography (CT) images of patients with locally advanced gastric cancer (GC) before and after neoadjuvant chemotherapy (NAC) in order to identify CT features that could predict pathological response to NAC. METHODS: We included patients with locally advanced GC who underwent gastrectomy after NAC from September 2016 to September 2021. We retrieved and collected the patients' clinicopathological characteristics and CT images before and after NAC. We analyzed CT features that could differentiate responders from non-responders and established a logistic regression equation based on these features. RESULTS: We included 97 patients (69 [71.1%] men; median [range] age, 60 [26-75] years) in this study, including 66 (68.0%) responders and 31 (32.0%) non-responders. No clinicopathological variable prior to treatment was significantly associated with pathological response. Out of 16 features, three features (ratio of tumor thickness reduction, ratio of reduction of primary tumor attenuation in arterial phase, and ratio of reduction of largest lymph node attenuation in venous phase) on logistic regression analysis were used to establish a regression equation that demonstrated good discrimination performance in predicting pathological response (area under receiver operating characteristic curve 0.955; 95% CI, 0.911-0.998). CONCLUSION: Logistic regression equation based on three CT features can help predict the pathological response of patients with locally advanced GC to NAC.

Prognostic Significance of PD-L1 Expression in Gastric Cancer Patients with Peritoneal Metastasis.

BACKGROUND: Recently, many studies have explored the relationship between the expression of programmed death ligand 1 (PD-L1) and prognosis in gastric cancer, but there is still controversy. Additionally, few studies have specifically investigated the expression of PD-L1 in patients with peritoneal metastasis. METHODS: Immunohistochemistry was used to analyze the expression of PD-L1 in gastric cancer patients with peritoneal metastasis. The combined positive score (CPS) was calculated to evaluate the expression of PD-L1, and the clinicopathological data were analyzed to explore prognostic significance. RESULTS: In total, 147 gastric cancer patients with peritoneal metastasis were enrolled. The negative PD-L1 expression was defined as a CPS < 1, and high PD-L1 expression was defined as a CPS ≥ 10. PD-L1 expression with CPS ≥ 1 and CPS-negative was detected in 67 (45.58%) and 80 (54.42%) patients, respectively. High PD-L1 expression at PD-L1 CPS ≥ 10 was detected in 21(14.29%) patients. The median overall survival (OS) was 18.53 months in the CPS < 10 group and 27.00 months in the CPS ≥ 10 group; the OS difference between the two groups was significant (p = 0.015). Multivariate analysis demonstrated that a poor Eastern Cooperative Oncology Group performance score (ECOG PS) (p = 0.002) and severe peritoneal metastasis (p = 0.033) were significantly associated with poor survival, while palliative chemotherapy (p = 0.002) and high PD-L1 expression (p = 0.008) were independent and significantly favorable prognostic factors. CONCLUSIONS: Our study demonstrated that PD-L1 expression was widely presented in gastric cancer patients with peritoneal metastasis, while a CPS no less than 10 predicted better prognosis.

Evaluating relapse-free survival as an endpoint for overall survival in adjuvant immunotherapy trials.

BACKGROUND: Relapse-free survival (RFS) has been considered a primary endpoint to assess the effects of immunotherapy in the adjuvant setting among patients with early-stage disease. However, it is not clear whether RFS is a valid surrogate endpoint for overall survival (OS) in this clinical context. METHODS: Phase II or III clinical trials of adjuvant immunotherapy that reported hazard ratios on OS and RFS were identified. We used a weighted regression analysis at the arm and trial levels to assess the efficacy of RFS as a surrogate for OS, quantified by the weighted coefficient of determination (R2). Strong correlations (R2 ≥ 0.7) at the arm and trial levels indicated valid surrogacy. The surrogate threshold effect was also evaluated. RESULTS: Fifteen high-quality randomized clinical trials involving 13 715 patients were included. At the arm level, moderate and strong associations were observed between RFS2-year and OS3-year (R2 = 0.58, 95% confidence interval [CI] = 0.25 to 0.92) and RFS3-year and OS5-year (R2 = 0.72, 95% CI = 0.38 to 1.00), respectively. At the trial level, a moderate association was observed between effect of treatment on RFS and OS (R2 = 0.63, 95% CI = 0.33 to 0.94). The surrogate threshold effect for RFS was 0.86. Consistent results were confirmed in several sensitivity analyses based on different trial phases, experimental arms, cancer types, and treatment strategies. CONCLUSIONS: Our meta-analysis failed to find a clinically strong association between RFS and OS in randomized clinical trials of adjuvant immunotherapy. Our findings challenge the use of RFS as the primary efficacy endpoint and suggest the use of OS in this clinical context.

Development and verification of a nomogram for predicting the prognosis of resectable gastric cancer with outlet obstruction.

BACKGROUND: The prognosis of patients with gastric cancer (GC) with gastric outlet obstruction (GOO) after gastrectomy is highly variable. In this study, we aimed to develop a nomogram to predict the prognosis of these patients. PATIENTS AND METHODS: Data from 218 GC patients with GOO who underwent gastrectomy at Sun Yat-sen University Cancer Center were retrospectively collected as a training cohort. The data of 59 patients with the same diagnosis who underwent gastrectomy at the First Affiliated Hospital of Guangxi Medical University were collected as an external verification cohort. A nomogram for the overall survival (OS) was developed using the Cox regression model in the training cohort, which was validated in a verification cohort. RESULTS: Multivariate analysis showed that the surgical procedure (P < 0.001), period of chemotherapy (P < 0.001), T stage (P = 0.006), N stage (P = 0.040), systemic immune-inflammatory index (SII) (P < 0.001), and fibrinogen level (P = 0.026) were independent factors affecting OS. The nomogram constructed on the aforementioned factors for predicting the 1- and 3-year OS achieved a Harrell's concordance index (C-index) of 0.756 and 0.763 for the training and verification cohorts, respectively. Compared with the 8th American Joint Committee on Cancer (AJCC) Tumour-Node-Metastasis (TNM) staging system, the nomogram had higher C-index values and areas under the curve (AUCs) and slightly higher net clinical benefit. CONCLUSION: Compared to the 8th AJCC staging system, the newly developed nomogram showed superior performance in predicting the survival of GC patients with GOO after gastrectomy.

Effects of Laparoscopic Radical Gastrectomy on Peritoneal Micrometastases of Gastric Cancer.

BACKGROUND: Some reports asserted that the stimulation of ultrasonic scalpel and the persistent state of carbon dioxide (CO2) pneumoperitoneum in laparoscopic surgery may affect the adhesion and invasion of gastric cancer (GC) cells. This study aimed to reveal the effects of laparoscopic radical gastrectomy on peritoneal micrometastases (PM) of GC. MATERIALS AND METHODS: Fifty-three patients who underwent laparoscopic radical gastrectomy for GC were enrolled in the study. The expressions of carcinoembryonic antigen (CEA) mRNA and dopa decarboxylase (DDC) mRNA in peritoneal lavage fluid were detected by reverse transcription-polymerase chain reaction. The positive rates of CEA mRNA and DDC mRNA in preoperative peritoneal lavage fluid (pre-CEA, pre-DDC) were compared with those in postoperative lavage fluid (post-CEA, post-DDC). The correlation between the expressions of pre-CEA and pre-DDC and clinicopathologic factors and disease-free survival was analyzed. RESULTS: There was no significant difference in the positive rates of pre-CEA and pre-DDC compared with those of post-CEA and post-DDC (all P>0.05). The positive rates of pre-CEA and pre-DDC increased with the increase of TNM stage, deepening of invasion, lymph node metastasis, and serosal invasion (all P<0.05), but had no correlation with tumor location, size, degree of differentiation, nerve invasion, and vascular invasion (all P>0.05). The disease-free survival in the combined positive patients was lower than that in the negative patients. CONCLUSIONS: Laparoscopic radical gastrectomy for GC is safe and feasible, without increasing the risk of PM. The PM of GC may be associated with late tumor stage, deep infiltration, lymph node metastasis, and serosal invasion.

Para-aortic lymph node tracing and dissection in advanced gastric cancer: Effectiveness of carbon nanoparticles injection through the no. 12b lymph node.

BACKGROUND AND OBJECTIVES: The relative effectiveness of tracers in guiding para-aortic lymph node dissection (PAND) in advanced gastric cancer is undefined. In this single-center, prospective study, we aimed to discuss the effectiveness of such tracers. MATERIALS AND METHODS: Between January 2015 and January 2016, 90 consecutive patients with stage T4a gastric cancer were evenly assigned to receive 0.2 mL of carbon nanoparticles (a), methylene blue (b), or no tracer (c) injection through no. 12b lymph nodes before PAND. RESULTS: There was no difference in the baseline characteristics between the three groups. Group A vs. B or C had a higher number of dissected lymph nodes (34.1 ± 9.8, 25.5 ± 5.5, and 22.6 ± 3.7; P < 0.001; B vs. C: P =0.321) and no. 16a2/b1 para-aortic lymph nodes (PANs; 11.8 ± 4.8, 7.0 ± 1.2, and 5.5 ± 1.2; P < 0.001; B vs. C: P =0.178) and similar rates of lymph node metastasis (20.9 ± 17.5%, 19.1 ± 15.1%, and 23.6 ± 19.7%; P = 0.511), positive dissected PAN (23.3% [7/30], 16.7% [5/30], and 16.7% [5/30]), surgery duration (252.9 + 35.4, 244.4 ± 29.0, and 250.3 + 29.9 min; P = 0.421), and blood loss (266.7 ± 115.5, 270.0 ± 82.6, and 260.0 ± 116.3 mL, P = 0.933). There was no common bile duct damage by tracer injection, and one case of duodenal stump fistula, one abdominal infection, and two anastomotic leakages in Groups A-C, respectively, were treated successfully. CONCLUSIONS: In advanced gastric cancer treatment, carbon nanoparticle injection into no. 12b nodes appears to better trace no. 16a2/b1 PAN.

Low Pretreatment Albumin-to-Globulin Ratio Predicts Poor Prognosis in Gastric Cancer: Insight From a Meta-Analysis.

BACKGROUND: In recent five years, reports regarding albumin-to-globulin ratio (AGR) and the survival of gastric cancer (GC) have emerged rapidly, yet their association remains controversial. This meta-analysis was aimed to provide an insight into the prognostic significance of pretreatment AGR in GC. METHODS: PubMed, Embase, Cochrane library, Web of Science, WanFang, China National Knowledge Infrastructure (CNKI) and VIP databases were searched for relevant studies, from inception to September 30, 2020. Individual hazard ratios (HRs) with their 95% confidence intervals (CIs) were combined by Stata 12.0 software to evaluate the association between pretreatment AGR and overall survival (OS) and disease-free survival/progression-free survival (DFS/PFS). RESULTS: A total of 8,305 patients with GC from 12 studies were included for further analysis. Pooled analyses indicated that low AGR was closely associated with worse OS (HR = 1.531, 95% CI: 1.300-1.803, P < 0.001) and worse DFS/PFS (HR = 2.008, 95% CI: 1.162-3.470, P = 0.012) in GC patients. Moreover, subgroup analyses demonstrated that the association between low AGR and worse OS remained constant despite variations in country, tumor stage, cut-off value, cut-off selection and treatment method. CONCLUSION: AGR could act as an efficient prognostic indicator for GC, and that low pretreatment AGR predicts poor prognosis in GC.