Background There was much hard work to study the trastuzumab resistance in HER2-positive gastric cancer (GC), but the information which would reveal this abstruse mechanism is little. In this study, we aimed to investigate the roles of tumor cell-derived CCL2 on trastuzumab resistance and overcome the resistance by treatment with the anti-CD40-scFv-linked anti-HER2 (CD40 ×HER2) bispecific antibody (bsAb). Methods We measured the levels of CCL2 expression in HER2-positive GC tissues, and revealed biological functions of tumor cell-derived CCL2 on tumor-associated macrophages (TAMs) and the trastuzumab resistance. Then, we developed CD40 ×HER2 bsAb, and examined the targeting roles on HER2 and CD40, to overcome the trastuzumab resistance without systemic toxicity. Results We found the level of CCL2 expression in HER2-postive GC was correlated with infiltration of TAMs, polarization status of infiltrated TAMs, trastuzumab resistance and survival outcomes of GC patients. On exposure to CCL2, TAMs decreased the M1-like phenotype, thereby eliciting the trastuzumab resistance. CCL2 activated the transcription of ZC3H12A, which increased K63-linked deubiquitination and K48-linked auto-ubiquitination of TRAF6/3 to inactivate NF-κB signaling in TAMs. CD40 ×HER2 bsAb, which targeted the CD40 to restore the ubiquitination level of TRAF6/3, increased the M1-like phenotypic transformation of TAMs, and overcame trastuzumab resistance without immune-related adversary effects (irAEs). Conclusions We revealed a novel mechanism of trastuzumab resistance in HER2-positive GC via the CCL2-ZC3H12A-TRAF6/3 signaling axis, and presented a CD40 ×HER2 bsAb which showed great antitumor efficacy with few irAEs.

Lymph node metastasis is one of the most important prognostic factors in patients with gastric cancer. An inadequate number of dissected lymph nodes is an independent risk factor affecting recurrence, even in patients who are node negative. Oddly, certain early-stage patients still experience recurrence or metastasis within a short time, even if they have undergone standard radical mastectomy. Many researchers have attributed these adverse events to lymph node micrometastasis (LNM), which is defined as a microscopic deposit of malignant cells of less than 2 mm in diameter. With the development of diagnostic tools such as immunohistochemistry and reverse transcription-polymerase chain reaction, the rate of detection of LNM has been constantly increasing. Although there is no clear consensus about risk factors for or the definitive clinical significance of LNM, the clinical impact of LNM is remarkable in gastric cancer. For minimally invasive treatment in particular, such as endoscopic submucosal dissection and laparoscopic surgery, accurate diagnosis of LNM is regarded as the potential key to maintaining the balance between curability and safety. This review provides an overview of the definition, detection and significance of LNM in gastric cancer. We also summarize several attention-drawing controversies regarding the treatment of patients who may have LNM.

Emerging evidence has highlighted that immune and stromal cells form the majority of the tumour microenvironment (TME), which plays important roles in tumour progression. The present study aimed to screen vital prognostic genes associated with the TME in gastric cancer (GC). The ESTIMATE algorithm was applied to calculate TME‑related scores, and the relationship between clinicopathological variables and these scores was analysed. Heatmaps and Venn plots were then used to visualize and screen differentially expressed genes. Furthermore, functional enrichment analysis was performed, and a protein‑protein interaction network was constructed. Kaplan‑Meier curves were generated to evaluate survival differences for each hub gene. Reverse transcription quantitative PCR was employed to evaluate the expression of the three hub genes in the validation cohort. The association between gene expression, clinicopathological variables and survival was also evaluated. Higher stromal scores were associated with worse outcomes in patients with GC. In addition, higher scores were significantly associated with a higher tumour grade, American Joint Committee on Cancer stage and T stage with regard to immune scores, stromal scores and ESTIMATE scores, respectively. In total, 644 upregulated intersecting genes and 126 downregulated genes were identified. Moreover, 71 TME‑associated hub genes were identified. Batch survival analysis revealed that higher expression of CXCR4, PTGFR and RGS1 was significantly associated with worse outcome. Subsequently, the relationship between high expression of RGS1 and poor prognosis was verified, and high expression of RGS1 was associated with poor differentiation. In conclusion, it was found that compared with immune cells, stromal cells may play a more important role in the prognosis of patients with GC. In addition, the influence of RGS1 expression on survival in GC patients was identified and verified, and high expression of RGS1 was found to be associated with a low differentiation degree of GC.

Background: Gastric cancer (GC) is one of the most common and fatal cancers worldwide. Effective biomarkers to aid the early diagnosis of GC, as well as predict the course of disease, are urgently needed. Hence, we explored the role and function of cadherin-6 (CDH6) in the diagnosis and prognosis of gastric cancer. Methods: The expression levels of CDH6 in cancerous and normal gastric tissue were analyzed using multiple public databases. Gene set enrichment analysis (GSEA) was performed using The Cancer Genome Atlas (TCGA) dataset. The diagnostic efficiency of CDH6 expression in GC patients was determined through receiver operating characteristic (ROC) curve analysis. The associations between clinical variables and CDH6 expression were evaluated statistically, and the prognostic factors for overall survival were analyzed by univariate and multivariate Cox regression. 44 GC tissue samples, 20 donor-matched adjacent normal tissue samples, and associated detailed clinical information, were collected from the Tianjin Medical University General Hospital. CDH6 expression levels were determined for further validation. Results: CDH6 was upregulated in GC samples compared to normal gastric tissue. Furthermore, GSEA identified the tricarboxylic acid (TCA) cycle, extracellular matrix (ECM) receptor interaction, glyoxylate and dicarboxylate metabolism, oxidative phosphorylation, and the pentose phosphate pathway as differentially enriched in GC tissue samples. According to the area under the ROC curve (AUC) values (AUC = 0.829 in the TCGA and 0.966 in the GSE54129 dataset), CDH6 expression was associated with high diagnostic efficacy. Patients with high CDH6 levels in their GC tissues had a higher T number (according to the TNM classification) and a worse prognosis than those with low CDH6 expression. Univariate and multivariate Cox regression analysis showed that CDH6 was an independent risk factor for overall survival (univariate: HR = 1.305, P = 0.002, multivariate: HR = 1.481, P < 0.001). Conclusion: CDH6 was upregulated in GC, and high CDH6 expression was indicative of a higher T number and a worse prognosis. Therefore, CDH6 represents a potentially independent molecular biomarker for the diagnostic and prognostic prediction of GC.

Objectives: Although laparoscopic distal gastrectomy has been widely used for distal gastric cancer, the best functional reconstruction type has not yet been established. Based on previous experience, we propose a modified uncut Roux-en-Y anastomosis. This study aimed to compare the outcomes of different intracorporeal anastomoses after laparoscopic distal gastrectomy. Methods: From April 2015 to August 2020, the data of 215 patients who underwent laparoscopic distal gastrectomy was collected. The patients were divided into 4 groups according to the digestive tract reconstruction method, Billroth-I, Billroth-II, Roux-en-Y, and the modified uncut Roux-en-Y. Clinicopathologic characteristics, surgery details, short-term outcomes, and postoperative nutritional status were analyzed. Results: The operation time of Billroth-I anastomosis was significantly shorter (216.2 ± 25.8 min, P < .001) than that of other methods. There was no difference in postoperative complications and OS among the 4 reconstruction methods. The incidences of esophagitis, gastritis, and bile reflux were significantly lower in the Roux-en-Y and uncut Roux-en-Y group (P < .001) 1 year after surgery. And the postoperative albumin and PNI levels in uncut Roux-en-Y group were higher than those in other groups(P < .05). On multivariate analysis, age and reconstruction type were independently related to esophagitis, gastritis, and bile reflux. Serum albumin and the prognostic nutritional index were significantly higher in the uncut Roux-en-Y group than other groups (P < .05). Conclusions: All 4 reconstruction techniques are feasible and safe. The Roux-en-Y and uncut Roux-en-Y are superior to Billroth-Ⅰ and Billroth-Ⅱ+Braun in terms of reflux esophagitis, gastritis, and bile reflux. Uncut Roux-en-Y may result in better PNI than the others.

Background: Increasing evidence indicated that the tumor microenvironment (TME) plays a critical role in tumor progression. This study aimed to identify and evaluate mRNA signature involved in lymph node metastasis (LNM) in TME for gastric cancer (GC). Methods: Gene expression and clinical data were downloaded from The Cancer Genome Atlas (TCGA). The ESTIMATE algorithm was used to evaluate the TME of GC. The heatmap and Venn plots were applied for visualizing and screening out intersect differentially expressed genes (DEGs) involved in LNM in TME. Functional enrichment analysis, gene set enrichment analysis (GSEA) and protein-protein interaction (PPI) network were also conducted. Furthermore, binary logistic regression analysis were employed to develop a 4-mRNAs signature for the LNM prediction. ROC curves were applied to validate the LNM predictive ability of the riskscore. Nomogram was constructed and calibration curve was plotted to verify the predictive power of nomogram. Results: A total of 88 LNM related DEGs were identified. Functional enrichment analysis and GSEA implied that those genes were associated with some biological processes, such as ion transportation, lipid metabolism and thiolester hydrolase activity. After univariate and multivariate logistic regression analysis, 4 mRNAs (RASSF2, MS4A2, ANKRD33B and ADH1B) were eventually screened out to develop a predictive model. ROC curves manifested the good performance of the 4-mRNAs signature. The proportion of patients with LNM in high-risk group was significantly higher than that in low-risk group. The C-index of nomogram from training and test cohorts were 0.865 and 0.765, and the nomogram was well calibrated. Conclusions: In general, we identified a 4-mRNAs signature that effectively predicted LNM in GC patients. Moreover, the 4-mRNAs signature and nomogram provide a guidance for the preoperative evaluation and postoperative treatment of GC patients.