Diffuse-type Gastric Cancer Research Articles

Construction and interpretation of machine learning-based prognostic models for survival prediction among intestinal-type and diffuse-type gastric cancer patients

BackgroundGastric cancer is one of the most common malignant tumors worldwide, with high incidence and mortality rates, and it has a complex etiology and complex pathological features. Depending on the tumor type, gastric cancer can be classified as intestinal-type and diffuse-type gastric cancer, each with distinct pathogenic mechanisms and clinical presentations. In recent years, machine learning techniques have been widely applied in the medical field, offering new perspectives for the diagnosis, treatment, and prognosis of gastric cancer patients.MethodsThis study recruited 2158 gastric cancer patients and constructed prognostic prediction models for both intestinal-type and diffuse-type gastric cancer. Clinical pathological data were collected from patients, and machine learning algorithms were used for feature selection and model construction. The performance of the models was validated with training and testing datasets. The Shapley additive explanations (SHAP) values were used to interpret the model predictions and identify the main factors that influence patient survival.ResultsIn the prognostic model for intestinal-type gastric cancer, the gradient boosting decision tree (GBDT) model demonstrated the best performance, with key features including pTNM, CA125, tumor size, CA199, and PALB. Similarly, in the prognostic model for diffuse-type gastric cancer, the GBDT model was utilized, with key features comprising pTNM, Borrmann type IV disease, lymphocyte (LYM), lactate dehydrogenase (LDH), potassium (K), perineural invasion (PNI), tumor size, and whole stomach location. Risk stratification analysis revealed that the prognosis of high-risk patients was significantly worse than that of low-risk patients.ConclusionMachine learning shows great potential in predicting survival outcomes of gastric cancer patients, providing strong support for the development of personalized treatment plans.

23 (PB011): scRNA-seq and single-cell spatial transcriptome of diffuse-type gastric cancer mouse model reveals a novel interaction between neutrophils and cancer cells

23 (PB011): scRNA-seq and single-cell spatial transcriptome of diffuse-type gastric cancer mouse model reveals a novel interaction between neutrophils and cancer cells

Integrated analysis to identify biological features and molecular markers of poorly cohesive gastric carcinoma (PCC)

As one of the two main histologic subtypes of gastric cancer (GC), diffuse-type gastric cancer (DGC) containing poorly cohesive gastric carcinoma (PCC) components has a worse prognosis and does not respond well to typical therapies. Despite the large number of studies revealing the complex pathogenic network of DGC, the molecular heterogeneity of DGC is still not fully understood. We obtained single-cell RNA-seq data and bulk data from the tumor immune single cell hub, the public gene expression omnibus, and the cancer genome atlas databases. A series of bioinformatics analyses were performed using R software. Immunofluorescence staining, hematoxylin and eosin staining, western blot, and functional experiments were used for experimental validation. Caudin-3, -4 and -7 were lowly expressed in DGC and their expression levels were further reduced in PCC. The PCC components were mainly located in the deeper layers of the DGC and had a high level of hypoxic Wnt/β-catenin signaling and stemness. We further identified Insulin Like Growth Factor Binding Protein 7 (IGFBP7) as a marker for PCC components in the deep layer. IGFBP7 is stimulated by hypoxia and promotes cancer cell invasiveness and reduced claudin expression. In addition, programmed death-1 ligand (PD-L1) was specifically expressed in the deep layer, reflecting deep layer-specific immunosuppression. The PCC components are predominantly situated in the deeper layers of DGC. Initial molecular characterization of these PCC components revealed distinct features, including low expression of claudin-3, -4, and -7, high expression of IGFBP7, and the presence of PD-L1. These molecular traits may partially account for the pronounced tumor heterogeneity observed in GC.

Subtotal versus total gastrectomy for distal diffuse-type gastric cancer.

Diffuse-type gastric carcinoma in an aggressive form of gastric cancer. Surgery is the only potentially curative treatment. It is controversial whether patients with diffuse-type gastric carcinoma should undergo total or subtotal gastrectomy when feasible. The aim of this study is to analyze the oncologic outcomes and overall survival of patients diagnosed with distal diffuse-type gastric cancer undergoing subtotal versus total gastrectomy with curative intent. This retrospective study included all patients with histologically confirmed diffuse-type distal gastric carcinoma and clinical staging cT1-4M0, who underwent surgery with curative intent between 2011 and 2020 in a Tertiary Referral Hospital in Chile. Clinical and pathological staging was conducted using the 8th Edition of the American Joint Committee on Cancer Classification. STG group was comprised by patients who underwent subtotal gastrectomy and TG group by patients who underwent total gastrectomy. Both groups were compared in relation to sociodemographic variables, pathology reports and perioperative data which were obtained from electronic medical records. Data analysis was obtained with Stata 16.1 Statistical Software. One hundred and thirty patients underwent curative intent surgery. Subtotal gastrectomy with D2-lymphadenectomy was completed in 68 patients (52%). An R0 resection was achieved in all patients. Median number of resected lymph nodes, tumor size, proximal margin and depth of invasion were similar in both groups. Pathologicstaging was similar between both groups, the most frequent being Stage 3(54%). After a median follow-up of 47 months [0.3-157], no difference was observed in overall survival between both groups (5-year-OS 63% in STG group versus 51% in TG group, p = 0.097). Oncologic and survival outcomes were similar in patients submitted to subtotal and total gastrectomy,suggesting that a subtotal gastrectomy with D2-lymphadenectomy for distal diffuse-type gastric carcinoma is not associated with a decrease in median overall survival and is an adequate surgical approach when technically feasible.

Differentially expressed microRNA in prognosis of gastric cancer with Lauren classification.

Gastric cancer (GC) is one of the most common tumors. There were several classifications of GC recently. The value of Lauren classification in evaluating the prognosis after radical gastrectomy was still unclear and the prognosis of gastric cancer remained relatively poor in the absence of prognostic biomarkers. This study aimed to explore microRNA (miRNA) in the prognosis of GC with different Lauren classification. A retrospective study of 1144patients was performed in this study. Quantificational reverse transcription-PCR (qRT-PCR) was used to examine the expression of miRNAs. Univariate and multivariate analysis were performed to evaluate prognosis value of Lauren classification. Total 1144 GC patients were recruited in this cohort, including 302 diffuse type (26.4%), 436 intestinal type (38.1%) and 406 mixed type (35.5%) GC. Multivariate analysis showed that Lauren classification, patients' age, tumor size, tumor infiltrating depth, vascular nerve infiltrating and metastatic lymph nodes ration were significantly correlated with GC patients' OS and DFS. The miR-141-3p, miR-200b-3p and miR-133a-5p were significantly down-regulated in diffuse type compared to intestinal type GC tissues, the miR-105-5p had significant lower expression in diffuse type compared with intestinal type and mixed type GC tissues. As a consequence of univariate analysis, low miR-141-3p in diffuse type GC showed significant worse OS and DFS than high miR-141-3p. Lauren classification was an independent prognostic factor in GC. MiR-141-3p was an independent prognostic factor and a promising prognostic biomarker in Lauren classification GC.

Diffuse Gastric Cancer: A Comprehensive Review of Molecular Features and Emerging Therapeutics.

Diffuse-type gastric cancer (DGC) accounts for approximately one-third of gastric cancer diagnoses but is a more clinically aggressive disease with peritoneal metastases and inferior survival compared with intestinal-type gastric cancer (IGC). The understanding of the pathogenesis of DGC has been relatively limited until recently. Multiomic studies, particularly by The Cancer Genome Atlas, have better characterized gastric adenocarcinoma into molecular subtypes. DGC has unique molecular features, including alterations in CDH1, RHOA, and CLDN18-ARHGAP26 fusions. Preclinical models of DGC characterized by these molecular alterations have generated insight into mechanisms of pathogenesis and signaling pathway abnormalities. The currently approved therapies for treatment of gastric cancer generally provide less clinical benefit in patients with DGC. Based on recent phase II/III clinical trials, there is excitement surrounding Claudin 18.2-based and FGFR2b-directed therapies, which capitalize on unique biomarkers that are enriched in the DGC populations. There are numerous therapies targeting Claudin 18.2 and FGFR2b in various stages of preclinical and clinical development. Additionally, there have been preclinical advancements in exploiting unique therapeutic vulnerabilities in several models of DGC through targeting of the focal adhesion kinase (FAK) and Hippo pathways. These preclinical and clinical advancements represent a promising future for the treatment of DGC.

Master Regulators of Causal Networks in Intestinal- and Diffuse-Type Gastric Cancer and the Relation to the RNA Virus Infection Pathway.

Causal networks are important for understanding disease signaling alterations. To reveal the network pathways affected in the epithelial-mesenchymal transition (EMT) and cancer stem cells (CSCs), which are related to the poor prognosis of cancer, the molecular networks and gene expression in diffuse- and intestinal-type gastric cancer (GC) were analyzed. The network pathways in GC were analyzed using Ingenuity Pathway Analysis (IPA). The analysis of the probe sets in which the gene expression had significant differences between diffuse- and intestinal-type GC in RNA sequencing of the publicly available data identified 1099 causal networks in diffuse- and intestinal-type GC. Master regulators of the causal networks included lenvatinib, pyrotinib, histone deacetylase 1 (HDAC1), mir-196, and erb-b2 receptor tyrosine kinase 2 (ERBB2). The analysis of the HDAC1-interacting network identified the involvement of EMT regulation via the growth factors pathway, the coronavirus pathogenesis pathway, and vorinostat. The network had RNA-RNA interactions with microRNAs such as mir-10, mir-15, mir-17, mir-19, mir-21, mir-223, mir-25, mir-27, mir-29, and mir-34. The molecular networks revealed in the study may lead to identifying drug targets for GC.

Deciphering the FGFR2 Code: Innovative Targets in Gastric Cancer Therapy.

Gastric cancer (GC) represents a major global health challenge as a highly prevalent disease with high mortality whose global incidence and mortality are predicted to worsen over the coming years. To date, our standard of care for advanced gastric cancer of combination chemotherapy and immunotherapy has a 1-year overall survival rate of 55%. Significant efforts have gone into identifying targetable alterations in gastric cancer, ultimately yielding the Fibroblast Growth Factor Receptors (FGFRs) family, specifically FGFR2 as a promising target. FGFR2 is overexpressed in GC, particularly diffuse-type GC, and is associated with poor prognostic outcomes. In recent years, there has been an increasing number of small molecule inhibitors and monoclonal antibodies targeting FGFR2 that have entered into clinical trials. Specifically for GC, these agents are currently being trialed in various phases as monotherapies or with standard-of-care treatments to make a clinically meaningful impact on what appears to be an important biological axis of GC. In this review, we outline the underlying biology of FGFR2, its putative role in GC, and the various FGFR2-targeted agents currently in clinical trials for gastric cancer patients as well as postulate some challenges in adopting these therapeutics for clinically meaningful benefit.

Construction and validation of the prognostic nomogram model for patients with diffuse-type gastric cancer based on the SEER database

ObjectiveThe prognostic factors of diffuse GC patients were screened the prognostic nomogram was constructed, and the prediction accuracy was verified.MethodsFrom 2006 to 2018, there were 2877 individuals pathologically diagnosed with diffuse gastric cancer; the clinicopathological features of these patients were obtained from the SEER database & randomly divided into a training cohort (1439) & validation cohort (1438).To create prognostic nomograms & choose independent prognostic indicators to predict the overall survival (OS) of 1, 3, & 5 years, log-rank & multivariate COX analysis were utilized & discrimination ability of nomogram prediction using consistency index and calibration curve.ResultsAge, T, N, M, TNM, surgical status, chemotherapy status, & all seven markers were independent predictors of OS (P < 0.05), & a nomogram of OS at 1, 3, & 5 years was created using these independent predictors. The nomogram's c-index was 0.750 (95% CI 0.734 ~ 0.766), greater than the TNM staging framework 0.658 (95%CI 0.639 ~ 0.677); the c-index was 0.753 (95% CI 0.737 ~ 0.769) as well as superior to the TNM staging mechanism 0.679 (95% CI 0.503–0.697). According to the calibration curve, the projected survival rate using the nomogram & the actual survival rate are in good agreement.ConclusionsPrognostic nomograms are useful tools for physicians to assess every individual's individualised prognosis & create treatment strategies for those with diffuse gastric cancer. They can reliably predict the prognosis for individuals with diffuse gastrointestinal carcinoma.

Drug-induced senescence by aurora kinase inhibitors attenuates innate immune response of macrophages on gastric cancer organoids

Diffuse-type gastric cancer (DGC) is a subtype of gastric cancer with aggressiveness and poor prognosis. It is of great significance to find sensitive drugs for DGC. In the current study, a total of 20 patient-derived organoids (PDOs) were analyzed for screening the therapeutic efficacy of small molecule kinases inhibitors on gastric cancers, especially the therapeutic difference between intestinal-type gastric cancer (IGCs) and DGCs. The IGCs are sensitive to multiple kinases inhibitors, while DGCs are resistant to most of these kinases inhibitors. It was found that DGCs showed drug-induced senescent phenotype after treatment by aurora kinases inhibitors (AURKi) Barasertib-HQPA and Danusertib. The cell diameter of cancer cells are increased with stronger staining of senescence-associated β-galactosidase (SA-β-GAL), and characteristic appearance of multinucleated giant cells. The senescent cancer cells secrete large amounts of chemokine MCP-1/CCL2, which recruit and induce macrophage to M2-type polarization in PDOs of DGC (DPDOs)-macrophage co-culture system. The up-regulation of local MCP-1/CCL2 can interact with MCP-1/CCL2 receptor (CCR2) expressed on macrophages and suppress their innate immunity to cancer cells. Overall, the special response of DGC to AURKi suggests that clinicians should select a sequential therapy with senescent cell clearance after AURKi treatment for DGC.

A retrospective study of adjuvant albumin-bound paclitaxel plus S-1 after D2 gastrectomy versus oxaliplatin plus S-1 in gastric cancer

Adjuvant oxaliplatin plus S-1 (SOX) chemotherapy for gastric cancer (GC) after D2 gastrectomy has been proven effective. There has yet to be a study that evaluates adjuvant nanoparticle albumin-bound paclitaxel (nab-paclitaxel) plus S-1. In this single-center, retrospective study, GC patients after D2 gastrectomy received either nab-paclitaxel plus S-1 (AS group) or SOX group were recruited between January 2018 and December 2020 in The First Affiliated Hospital of Zhejiang University. Intravenous nab-paclitaxel 120 mg/m2 or 260 mg/m2 and oxaliplatin 130 mg/m2 were administered as eight 3 week cycle, especially in the AS and SOX group. Patients received S-1 twice daily with a dose of 40 mg/m2 in the two groups on days 1–14 of each cycle. The end points were disease-free survival (DFS) rate at 3 years and adverse events (AEs). There were 56 eligible patients, 28 in the AS group and 35 in the SOX group. The 3 year DFS rate was 78.0% in AS group versus 70.7% in SOX group (p = 0.46). Subgroup analysis showed that the patients with signet-ring positive in the AS group had a prolonged DFS compared with the SOX group (40.0 vs. 13.8 m, p = 0.02). The diffuse-type GC or low differentiation in the AS group was associated with numerically prolonged DFS compared with the SOX group, but the association was not statistically significant (p = 0.27 and p = 0.15 especially). Leukopenia (14.3%) were the most prevalent AEs in the AS group, while thrombocytopenia (28.5%) in the SOX group. Neutropenia (7.1% in AS group) and thrombocytopenia (22.8% in SOX group) were the most common grade 3 or 4 AEs. In this study analyzing past data, a tendency towards a greater 3 year DFS was observed when using AS regimen in signet-ring positive patients. AS group had fewer thrombocytopenia compared to SOX group. More studies should be conducted with larger sample sizes.

Tumor cell enrichment by tissue suspension improves sensitivity to copy number variation in diffuse gastric cancer with low tumor content

The detection of copy number variations (CNVs) and somatic mutations in cancer is important for the selection of specific drugs for patients with cancer. In cancers with sporadic tumor cells, low tumor content prevents the accurate detection of somatic alterations using targeted sequencing. To efficiently identify CNVs, we performed tumor cell enrichment using tissue suspensions of formalin-fixed paraffin-embedded (FFPE) tissue sections with low tumor cell content. Tumor-enriched and residual fractions were separated from FFPE tissue suspensions of intestinal and diffuse-type gastric cancers containing sporadic tumor cells, and targeted sequencing was performed on 225 cancer-related genes. Sequencing of a targeted panel of cancer-related genes using tumor-enriched fractions increased the number of detectable CNVs and the copy number of amplified genes. Furthermore, CNV analysis using the normal cell-enriched residual fraction as a reference for CNV scoring allowed targeted sequencing to detect CNV characteristics of diffuse-type gastric cancer with low tumor content. Our approach improves the CNV detection rate in targeted sequencing with tumor enrichment and the accuracy of CNV detection in archival samples without paired blood.

Senescent Fibroblasts Potentiate Peritoneal Metastasis of Diffuse-type Gastric Cancer Cells via IL-8-mediated Crosstalk.

Diffuse-type gastric cancer (DGC) often forms peritoneal metastases, leading to poor prognosis. However, the underlying mechanism of DGC-mediated peritoneal metastasis is poorly understood. DGC is characterized by desmoplastic stroma, in which heterogeneous cancer-associated fibroblasts (CAFs), including myofibroblastic CAFs (myCAFs) and senescent CAFs (sCAFs), play a crucial role during tumor progression. This study investigated the CAF subtypes induced by GC cells and the role of sCAFs in peritoneal metastasis of DGC cells. Conditioned medium of human DGC cells (KATOIII, NUGC-4) and human intestinal-type GC (IGC) cells (MKN-7, N87) was used to induce CAFs. CAF subtypes were evaluated by analyzing the expression of α-smooth muscle actin (α-SMA), senescence-associated β-galactosidase (SA-β-gal), and p16 in human normal fibroblasts (GF, FEF-3). A cytokine array was used to explore the underlying mechanism of GC-induced CAF subtype development. The role of sCAFs in peritoneal metastasis of DGC cells was analyzed using a peritoneally metastatic DGC tumor model. The relationships between GC subtypes and CAF-related markers were evaluated using publicly available datasets. IGC cells significantly induced α-SMA+ myCAFs by secreting transforming growth factor-β, whereas DGC cells induced SA-β-gal+/p16+ sCAFs by secreting interleukin (IL)-8. sCAFs further secreted IL-8 to promote DGC cell migration. In vivo experiments demonstrated that co-inoculation of sCAFs significantly enhanced peritoneal metastasis of NUGC-4 cells, which was attenuated by administration of the IL-8 receptor antagonist navarixin. p16 and IL-8 expression was significantly associated with poor prognosis of DGC patients. sCAFs promote peritoneal metastasis of DGC via IL-8-mediated crosstalk.

Expression of the Folate Receptor Proteins FOLR1 and FOLR2 in Correlation With Clinicopathological Variables of Gastric Cancer.

Gastric cancer (GC) remains a leading cause of cancer-related mortality worldwide, owing to its aggressive nature and poor prognosis. The role of folate receptors, particularly folate receptor 1 (FOLR1) and folate receptor 2 (FOLR2), in cancer has been increasingly recognized due to their overexpression in various malignancies including gastric cancer, and its potential implications in cancer progression, treatment resistance and as therapeutic targets. To evaluate the expression patterns of FOLR1 and FOLR2 in GC patients' tissue and blood specimens and to correlate these patterns with clinicopathological variables. A total of 58 gastric cancer patients were enrolled at the Regional Cancer Centre (RCC) from March 2017 to March 2020. Immunohistochemical analysis was performed to examine the expression of FOLR1 and FOLR2 in formalin-fixed paraffin-embedded (FFPE) tissue samples. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to analyze FOLR1 and FOLR2 expression in blood samples. Statistical analyses were conducted using chi-square tests, independent T-tests, and Kaplan-Meier survival analysis. FOLR1 and FOLR2 were overexpressed in 82.76% and 70.69% of gastric cancer tissues, respectively. High expression levels of FOLR1 were significantly associated with the diffuse type of gastric cancer (p<0.005). qRT-PCR showed significant overexpression of FOLR1 in gastric cancer blood samples compared to control samples, with a median fold change of approximately 14.18 times. Conversely, FOLR2 was significantly underexpressed in gastric cancer samples, with a fold change of 0.30. However, no significant correlation was found between FOLR2 expression and the clinicopathological features. The overall survival analysis did not show a significant difference in survival rates based on the expression levels of FOLR1 and FOLR2. This study highlights the differential expression patterns of FOLR1 and FOLR2 in gastric cancer and underscores the complexity of their roles in cancer biology. While FOLR1 shows potential as a biomarker for gastric cancer due to its overexpression, further studies are needed to fully elucidate the therapeutic and prognostic implications of folate receptors in gastric cancer.

Distinct characteristics of distant metastasis in early-onset gastric cancer patients compared to late-onset patients: An observational study.

Presently, there is limited understanding of the features of distant metastasis in early-onset gastric cancer (GC). To explore these disparities, a retrospective study utilizing the Surveillance, Epidemiology, and End Results (SEER) database was undertaken. The SEER database was utilized to extract patient data, and multivariate logistic regression analysis was employed to identify the risk factors associated with distant metastasis and liver metastasis. Propensity score matching (PSM) was used to compare the occurrence of liver metastasis among patients based on their age at diagnosis. The study included 2684 early-onset GC patients and 33,289 late-onset GC patients. Preliminary data analysis indicated that early-onset GC patients exhibited more aggressive characteristics such as poor cell differentiation, advanced T stage, and a higher incidence of distant metastasis, excluding liver metastasis. Multivariate logistic regression analysis identified younger age as an independent risk factor for distant metastasis, along with T stage, lymph node metastasis (LNM), and tumor size (>3 cm). Another regression analysis revealed that younger age, diffuse type, and female gender were protective factors against liver metastasis. Through PSM, 3276 early-onset GC patients were matched with an equal number of late-onset GC patients, revealing that patients with early-onset GC had fewer instances of liver metastasis but a higher prevalence of distant metastasis. Our findings suggest that early-onset serves as a protective factor against liver metastasis in GC, while it poses a risk for distant metastasis, likely influenced by the increased prevalence of diffuse-type GC in early-onset patients.

Prognostic role of MUCIN family and its relationship with immune characteristics and tumor biology in diffuse-type gastric cancer

The main component of O-glycoproteins, mucin, is known to play important roles in physiological conditions and oncogenic processes, particularly correlated with poor prognosis in different carcinomas. Diffuse-type gastric cancer (DGC) has long been associated with genomic stability and unfavorable clinical outcomes. To investigate further, we obtained clinical information and the RNA-seq data of the TCGA-STAD cohort. Through the use of unsupervised clustering methods and GSEA, we identified two distinct clusters, characterized by higher and lower expression of MUC2 and MUC20, denoted as cluster 1 and cluster 2, respectively. Subsequently, employing CIBERSORT, it was determined that cluster 2 exhibited a higher tumor mutation burden (TMB) and a greater abundance of CD8+ T cells and activated CD4+ memory T cells, in addition to immune checkpoints (ICPs). On the other hand, cluster 1 showed a lower TIDE score estimation, indicating a higher probability of tumor immune escape. Furthermore, overexpression of MUC15 and MUC20 was confirmed through qPCR and Western blotting, and their specific roles in mediating the epithelial-mesenchymal transition (EMT) process of GC cells (SNU484 and Hs746t) were validated via CCK-8 assay and wound healing assay in vitro. These findings highlight the potential prognostic value of MUC20 and offer insights into the prospects of immunotherapy for DGC by targeting MUC20.

Stool Protein Mass Spectrometry Identifies Biomarkers for Early Detection of Diffuse-type Gastric Cancer.

There is a high unmet need for early detection approaches for diffuse gastric cancer (DGC). We examined whether the stool proteome of mouse models of gastric cancer (GC) and individuals with hereditary diffuse gastric cancer (HDGC) have utility as biomarkers for early detection. Proteomic mass spectrometry of the stool of a genetically engineered mouse model driven by oncogenic KrasG12D and loss of p53 and Cdh1 in gastric parietal cells [known as Triple Conditional (TCON) mice] identified differentially abundant proteins compared with littermate controls. Immunoblot assays validated a panel of proteins, including actinin alpha 4 (ACTN4), N-acylsphingosine amidohydrolase 2 (ASAH2), dipeptidyl peptidase 4 (DPP4), and valosin-containing protein (VCP), as enriched in TCON stool compared with littermate control stool. Immunofluorescence analysis of these proteins in TCON stomach sections revealed increased protein expression compared with littermate controls. Proteomic mass spectrometry of stool obtained from patients with HDGC with CDH1 mutations identified increased expression of ASAH2, DPP4, VCP, lactotransferrin (LTF), and tropomyosin-2 relative to stool from healthy sex- and age-matched donors. Chemical inhibition of ASAH2 using C6 urea ceramide was toxic to GC cell lines and GC patient-derived organoids. This toxicity was reversed by adding downstream products of the S1P synthesis pathway, which suggested a dependency on ASAH2 activity in GC. An exploratory analysis of the HDGC stool microbiome identified features that correlated with patient tumors. Herein, we provide evidence supporting the potential of analyzing stool biomarkers for the early detection of DGC. Prevention Relevance: This study highlights a novel panel of stool protein biomarkers that correlate with the presence of DGC and has potential use as early detection to improve clinical outcomes.

Family history and gastric cancer incidence and mortality in Asia: a pooled analysis of more than half a million participants

BackgroundThe family history of gastric cancer holds important implications for cancer surveillance and prevention, yet existing evidence predominantly comes from case–control studies. We aimed to investigate the association between family history of gastric cancer and gastric cancer risk overall and by various subtypes in Asians in a prospective study.MethodsWe included 12 prospective cohorts with 550,508 participants in the Asia Cohort Consortium. Cox proportional hazard regression was used to estimate study-specific adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between family history of gastric cancer and gastric cancer incidence and mortality, then pooled using random-effects meta-analyses. Stratified analyses were performed for the anatomical subsites and histological subtypes.ResultsDuring the mean follow-up of 15.6 years, 2258 incident gastric cancers and 5194 gastric cancer deaths occurred. The risk of incident gastric cancer was higher in individuals with a family history of gastric cancer (HR 1.44, 95% CI 1.32–1.58), similarly in males (1.44, 1.31–1.59) and females (1.45, 1.23–1.70). Family history of gastric cancer was associated with both cardia (HR 1.26, 95% CI 1.00–1.60) and non-cardia subsites (1.49, 1.35–1.65), and with intestinal- (1.48, 1.30–1.70) and diffuse-type (1.59, 1.35–1.87) gastric cancer incidence. Positive associations were also found for gastric cancer mortality (HR 1.30, 95% CI 1.19–1.41).ConclusionsIn this largest prospective study to date on family history and gastric cancer, a familial background of gastric cancer increased the risk of gastric cancer in the Asian population. Targeted education, screening, and intervention in these high-risk groups may reduce the burden of gastric cancer.

RAC1-mediated integrin alpha-6 expression in E-cadherin-deficient gastric cancer cells promotes interactions with the stroma and peritoneal dissemination

Diffuse-type gastric cancer (DGC) is a subtype of gastric cancer that is prone to peritoneal dissemination, with poor patient prognosis. Although intercellular adhesion loss between cancer cells is a major characteristic of DGCs, the mechanism underlying the alteration in cell-to-extracellular matrix (ECM) adhesion is unclear. We investigated how DGCs progress and cause peritoneal dissemination through interactions between DGC cells and the tumour microenvironment (TME). P53 knockout and KRASG12V-expressing (GAN-KP) cells and Cdh1-deleted GAN-KP (GAN-KPC) cells were orthotopically transplanted into the gastric wall to mimic peritoneal dissemination. The GAN-KPC tumour morphology was similar to that of human DGCs containing abundant stroma. RNA sequencing revealed that pathways related to Rho GTPases and integrin-ECM interactions were specifically increased in GAN-KPC cells compared with GAN-KP cells. Notably, we found that Rac Family Small GTPase 1 (RAC1) induces Integrin Subunit Alpha 6 (ITGA6) trafficking, leading to its enrichment on the GC cell membrane. Fibroblasts activate the FAK/AKT pathway in GC cells by mediating extracellular matrix (ECM)-Itga6 interactions, exacerbating the malignant phenotype. In turn, GC cells induce abnormal expression of fibroblast collagen and its transformation into cancer-associated fibroblasts (CAFs), resulting in DGC-like subtypes. These findings indicate that Cdh1 gene loss leads to abnormal expression and changes in the subcellular localization of ITGA6 through RAC1 signalling. The latter, through interactions with CAFs, allows for peritoneal dissemination.

Genomic and Pathologic Profiling of Very Well-Differentiated Gastric Adenocarcinoma of Intestinal Type: A Study With Emphasis on Diffuse-Type Transformation.

Very well-differentiated adenocarcinoma of intestinal type is a distinct subtype of gastric cancer characterized by anastomosing glands with a hand-in-hand pattern and low-grade cytologic atypia resembling intestinal metaplasia. This is a slow-growing neoplasm with an indolent clinical course; however, a subset demonstrates transformation into adenocarcinoma with higher-grade histology, typically diffuse-type carcinoma, and behaves aggressively. This study aimed to better characterize the genomic and pathologic features, with a focus on factors associated with diffuse-type transformation. A total of 58 cases with (n=31) and without (n=27) diffuse-type transformation were analyzed for molecular and pathologic features. First, comprehensive deep DNA sequencing was conducted in 18 cases (discovery cohort), followed by a digital droplet polymerase chain reaction of hot spot RHOA mutations in 40 cases (validation cohort). In total, RHOA mutations were the most common alteration (34%), followed by loss of ARID1A (12%), p53 alterations (10%), and CLDN18 :: ARHGAP26/6 fusions (3.4%). FGFR2 amplification was identified in an advanced case with a p53 alteration. Altered p53 expression was recognized only in higher-grade components and was significantly associated with advanced disease ( P =0.0015) and diffuse-type transformation ( P =0.026). A mixed mucin phenotype was also strongly correlated with advanced disease ( P <0.001) and diffuse-type transformation ( P <0.001). Decreased E-cadherin expression was frequently observed (74%) in poorly cohesive components. This study demonstrated that a subset of RHOA -mutant diffuse-type gastric cancers develops through the transformation of very well-differentiated adenocarcinoma of intestinal type. Our observations suggest a mixed mucin phenotype as a risk factor and alterations in p53 and E-cadherin as drivers of diffuse-type transformation.