Gastric Cancer: Recent Molecular Classification Advances, Racial Disparity, and Management Implications

Traditional Chinese Medicine in the treatment of chronic atrophic gastritis, precancerous lesions and gastric cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Chronic atrophic gastritis (CAG), precancerous lesions of gastric cancer (PLGC), and gastric cancer (GC), seriously threaten human health. Traditional Chinese medicine (TCM) has been employed in the treatment of chronic diseases for a long time and has shown remarkable efficacy.

AIM OF THE STUDY

Recently, there has been an increasing use of TCM in treating CAG, PLGC, and GC. The objective of this study is to compile a comprehensive overview of the existing research on the effects and molecular mechanisms of TCM, including formulas, single herbs, and active components.

MATERIALS AND METHODS

To obtain a comprehensive understanding of traditional use of TCM in treating these diseases, we reviewed ancient books and Chinese literature. In addition, keywords such as "TCM", "CAG", "PLGC", "GC", and "active ingredients" were used to collect modern research on TCM published in databases such as CNKI, Web of Science, and Pubmed up to April 2024. All collected information was then summarized and analyzed.

RESULTS

This study analyzed 174 articles, which covered the research progress of 20 TCM formulas, 14 single herbs, and 50 active ingredients in treating CAG, PLGC, and GC. Sources, effects, and molecular mechanisms of the TCM were summarized.

CONCLUSIONS

This article reviews the progress of TCM in the management of CAG, PLGC, and GC, which will provide a foundation for the clinical application and further development of TCM.

Differences in Ancestry and Presence of Gastric Precursor Lesions in Individuals With Young- and Average-Onset Gastric Cancer

BACKGROUND

There has been a paradoxical rise in young-onset gastric cancer (YOGC), defined as gastric cancer (GC) diagnosed before age 50. Precursor lesions may contribute to pathogenesis, though their role in progression to different histologic subtypes is unclear. The impact of self-reported race is also poorly characterized and may be unreliable as a proxy for genetic differences. We aimed to compare differences in histology and genetic ancestry between YOGC and average-onset gastric cancer (AOGC).

METHODS

This retrospective cohort included all patients with GC at Memorial Sloan Kettering (MSK) from January 2013 to March 2021. Data on demographics, tumor characteristics, and precursor lesions were collected. Genetic ancestry was inferred from MSK-Integrated Mutation Profiling of Actionable Cancer Targets panel.

RESULTS

Of 1685 individuals with GC, 290 had YOGC. Compared to AOGC, individuals with YOGC tended to be female, Hispanic, foreign-born, and feature diffuse-type histology. YOGC was less likely to have precursor lesions, including intestinal metaplasia (20% vs. 37%, p < 0.01) and dysplasia (4% vs. 14%, p < 0.01). Of 560 patients with ancestry data, 127 had YOGC. Admixed, East Asian, and South Asian ancestries were more likely to present with YOGC while Europeans presented with AOGC. Intestinal metaplasia was enriched among East Asians, maintained when stratifying by histology and GC onset.

CONCLUSIONS

We observed YOGC was more common in East and South Asians, and while YOGC may be less likely to develop in the setting of precursor lesions these high-risk states may also be enriched in East Asians. Future research is needed to understand drivers behind such differences and outcome disparities given these individuals may be less amenable to endoscopic interventions.

Cluster classification of a Brazilian gastric cancer cohort reveals remarkable populational differences in normal p53 rate

BACKGROUND

Queiroz et al. showed that the application of cluster methodology for classifying gastric cancer is suitable and efficient within a Brazilian cohort, which is known for its population heterogeneity. The study highlighted the potential utilization of this method within public health services due to its low-cost, presenting a viable means to improve the diagnosis and prognosis of gastric cancer.

BACKGROUND

Our Brazilian cohort with gastric cancer has a distinct distribution between mutated and normal p53.

BACKGROUND

New genetic marker-based classifications improve gastric cancer diagnosis accuracy.

BACKGROUND

Machine learning integration enhances predictive value in gastric cancer diagnosis.

BACKGROUND

Molecular biomarkers complement clinical decisions, advancing personalized medicine.

OBJECTIVE

Gastric adenocarcinoma remains an aggressive disease with a poor prognosis, as evidenced by a 5-year survival rate of approximately 31%. The histological classifications already proposed do not accurately reflect the high biological heterogeneity of this neoplasm, particularly in diverse populations, and new classification systems using genetic markers have recently been proposed. Following these newly proposed models, we aimed to assess the cluster distribution in a Brazilian cohort. Furthermore, we evaluated whether the inclusion of other clinical and histological parameters could enhance the predictive value.

METHODS

We used a previously described four-immunohistochemistry/EBER-ISH marker to classify a cohort of 30 Brazilian patients with gastric adenocarcinoma into five different clusters and compared the distribution with other genetically diverse populations. Furthermore, we used artificial intelligence methods to evaluate whether other clinical and pathological parameters could improve the results of the methodology.

RESULTS

Disclosing the genetic variability between populations, we observed a more balanced distribution of the aberrant/normal p53 ratio (0.6) between patients negative for the other markers tested, unlike previous studies with Asian and North American populations. In addition, decision tree analysis reinforced the efficiency of these new classifications, as the stratification accuracy was not altered with or without additional data.

CONCLUSION

Our study underscores the importance of local research in characterizing diverse populations and highlights the complementary role of molecular biomarkers in personalized medicine for gastric adenocarcinoma, enhancing diagnostic accuracy and potentially improving survival rates.

Socioeconomic disparities and the genomic landscape of gastric cancer

The genomic characteristics of Peruvian patients with gastric adenocarcinoma from diverse socioeconomic backgrounds were examined in consideration of the possibility that patients from different socioeconomic backgrounds may be exposed to different risk factors. We conducted a prospective pilot study in two Peruvian cities (Lima and Ica). This study enrolled 15 patients from low socioeconomic status (LSES) and 15 patients from medium/high socioeconomic status (MHSES). The genomic profiling of gastric adenocarcinoma samples was done through the FoundationOne CDx platform. We compared the genomic characteristics and the need for targeted therapy and immunotherapy between LSES and MHSES. The genes with higher rates of alterations were TP53 (73.3% vs. 50.0%, P = 0.2635); CDH1 (26.7% vs. 28.6%, P = 1); CDKN2A (20.0% vs. 28.6%, P = 1); KRAS (33.3% vs. 7.1%, P = 0.1686); ARID1A (20.0% vs. 14.3%, P = 1); MLL2 (13.3% vs. 21.4%, P = 1) and SOX9 (33.3% vs. 0.0%, P = 0.0421) in LSES versus HMSES, respectively. There was no significant difference in tumor mutational burden (P = 0.377) or microsatellite status (P = 1). The LSES group had a higher need for targeted therapy or immunotherapy according to gene involvement and alterations. A significant genomic difference exists among patients with gastric adenocarcinoma of different socioeconomic status, which may result in a different need for targeted therapy and immunotherapy.

Risk, Predictive Factors, and Nomogram of Liver Metastatic Gastroesophageal Junction Cancer: A New Study Based on the Surveillance, Epidemiology, and End Results Database

BACKGROUND AND OBJECTIVES

 Liver metastases are associated with a poor prognosis in gastroesophageal junction (GEJ) cancer patients. The high rate of liver involvement is attributed to the unique anatomical location of the GEJ, which is close to the liver. Patients with liver metastasis typically have advanced, unresectable disease and limited treatment options. Therefore, early detection and prediction are crucial to guide appropriate treatment planning and improve the outcomes for patients with GEJ cancer at risk of liver metastases. Using data from the Surveillance, Epidemiology, and End Results (SEER) database, the present study aimed to elucidate the incidence and risk factors of liver metastases in GEJ cancer patients diagnosed between 2010 and 2019.

METHODS

This research employed univariable and multivariable logistic regression models to identify risk factors for the development of liver metastases. A predictive nomogram for liver metastases was developed and assessed. Patients' overall survival (OS) with liver metastases was analyzed using the Kaplan-Meier method.

RESULTS

The study included 1,322 eligible patients with GEJ cancer, 181 (13.6%) of whom were diagnosed with liver metastases. The median overall survival (mOS) for patients with liver metastasis was approximately eight months, compared to a shorter mOS for patients without liver metastasis (P < 0.001). Factors significantly associated with the occurrence of liver metastasis included N3 stage (OR: 1.84; 95% CI: (1.13-2.96); P < 0.001), surgery (OR: 0.09; 95% CI: (0.06-0.14); P < 0.001), lung metastasis (OR: 2.88; 95% CI: (1.78-4.63); P < 0.001), chemotherapy (OR: 0.54; 95% CI: (0.32-0.87); P < 0.001), and radiation therapy (OR: 0.33; 95% CI: (0.25-0.45); P < 0.001). The nomogram demonstrated good performance in predicting liver metastases in GEJ cancer patients (c-index: 0.820).

CONCLUSIONS

The study identified lymph node status, surgical, lung metastasis, chemotherapy, and radiation as important predictors of outcomes for patients with GEJ cancer. The developed nomogram might be a valuable tool for predicting the risk of liver metastases in GEJ cancer patients, potentially enhancing clinical decision-making processes. By predicting the risk of liver metastasis occurrence, clinicians might intervene in patients with GEJ cancers as early as possible.

Prognostic relevance of the most predominant and least differentiated grades of gastric adenocarcinoma after curative gastrectomy

BACKGROUND

Prognostic relevance of differentiation grade has remained controversial in gastric adenocarcinoma (GAC) after curative resection.

METHODS

GAC patients who underwent curative gastrectomy were analyzed. Differentiation grade was evaluated according to either the most predominant or least differentiated component. Impacts of clinicopathologic parameters on postoperative recurrence and nodal metastasis were analyzed by the multivariate Cox regression analysis in pT1/2/3/4a and pT1b/2/3 GAC and by the logistic regression analysis in pT1b GAC, respectively.

RESULTS

154 patients with GAC, consisting of 34 pT1a (recurrence rate 0%), 45 pT1b (4.4%), 18 pT2 (22.2%), 40 pT3 (35.0%), and 17 pT4a (76.5%), were included. In pT1/2/3/4a GAC, recurrence was significantly associated with only depth of invasion (pT) and grade of venous invasion (VI), although either mode of differentiation grade was significantly associated with pT by the Spearman's rank correlation test. Next, given no recurrence in pT1a and high-grade histopathology in nearly all pT4a, pT1b/2/3 GAC was analyzed, revealing that recurrence was significantly associated with only VI grade and nodal metastasis. Finally, nodal metastasis was not found in any pT1a GAC, of which 44.1% was predominantly high-grade. In pT1b GAC, nodal metastasis was irrelevant to either mode of differentiation grade, tumor size, and ulceration status but was only associated with lymphatic invasion, suggesting that endoscopic resection of pT1 GAC with negative margin can be curative even with high-grade histopathology.

CONCLUSION

Either mode of differentiation grade revealed limited prognostic relevance after curative gastrectomy. Our results may warrant a controversy over current curability evaluation of endoscopic GAC resection.

Analyzing the expression and clinical significance of CENPE in gastric cancer

BACKGROUND

Gastric cancer (GC) is a prevalent type of malignant gastrointestinal tumor. Many studies have shown that CENPE acts as an oncogene in some cancers. However, its expression level and clinical value in GC are not clear.

METHODS

Obtaining clinical data information on gastric adenocarcinoma from TCGA and GEO databases. The gene expression profiling interaction analysis (GEPIA) was used to evaluate the relationship between prognosis and CENPE expression in gastric cancer patients. Utilizing the UALCAN platform, the correlation between CENPE expression and clinical parameters was examined. Functions and signaling pathways of CENPE were analyzed using the Gene Ontology (GO), the Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA). The association between immunological infiltrating cells and CENPE expression was examined using TIMER2.0. Validation was performed by real-time quantitative PCR (qPT-PCR) and immunohistochemical analysis.

RESULTS

According to the analysis of the GEPIA database, the expression of CENPE is increased in gastric cancer tissues compared to normal tissues. It was also found to have an important relationship with the prognosis of the patient (p<0.05). The prognosis was worse and overall survival was lower in individuals with increased expression of CENPE. In line with the findings of the GEPIA, real-time fluorescence quantitative PCR (qPT-PCR) confirmed that CENPE was overexpressed in gastric cancer cells. Furthermore, It was discovered that H. pylori infection status and tumor grade were related to CENPE expression. Enrichment analysis revealed that CENPE expression was linked to multiple biological functions and tumor-associated pathways. CENPE expression also correlated with immune-infiltrating cells in the gastric cancer microenvironment and was positively connected to NK cells and mast cells. According to immunohistochemical examination, paracancerous tissues had minimal expression of CENPE, but gastric cancer showed significant expression of the protein.

CONCLUSIONS

According to our findings, CENPE is substantially expressed in GC and may perhaps contribute to its growth. CENPE might be a target for gastric cancer therapy and a predictor of a bad prognosis.

Access to cancer clinical trials for racialised older adults: an equity-focused rapid scoping review protocol

BACKGROUND

The intersection of race and older age compounds existing health disparities experienced by historically marginalised communities. Therefore, racialised older adults with cancer are more disadvantaged in their access to cancer clinical trials compared with age-matched counterparts. To determine what has already been published in this area, the rapid scoping review question are: what are the barriers, facilitators and potential solutions for enhancing access to cancer clinical trials among racialised older adults?

METHODS

We will use a rapid scoping review methodology in which we follow the six-step framework of Arksey and O'Malley, including a systematic search of the literature with abstract and full-text screening to be conducted by two independent reviewers, data abstraction by one reviewer and verification by a second reviewer using an Excel data abstraction sheet. Articles focusing on persons aged 18 and over who identify as a racialised person with cancer, that describe therapies/therapeutic interventions/prevention/outcomes related to barriers, facilitators and solutions to enhancing access to and equity in cancer clinical trials will be eligible for inclusion in this rapid scoping review.

ETHICS AND DISSEMINATION

All data will be extracted from published literature. Hence, ethical approval and patient informed consent are not required. The findings of the scoping review will be submitted for publication in a peer-reviewed journal and presentation at international conferences.

LncRNA MIR200CHG inhibits EMT in gastric cancer by stabilizing miR-200c from target-directed miRNA degradation

Gastric cancer (GC) is a heterogeneous disease, threatening millions of lives worldwide, yet the functional roles of long non-coding RNAs (lncRNAs) in different GC subtypes remain poorly characterized. Microsatellite stable (MSS)/epithelial-mesenchymal transition (EMT) GC is the most aggressive subtype associated with a poor prognosis. Here, we apply integrated network analysis to uncover lncRNA heterogeneity between GC subtypes, and identify MIR200CHG as a master regulator mediating EMT specifically in MSS/EMT GC. The expression of MIR200CHG is silenced in MSS/EMT GC by promoter hypermethylation, associated with poor prognosis. MIR200CHG reverses the mesenchymal identity of GC cells in vitro and inhibits metastasis in vivo. Mechanistically, MIR200CHG not only facilitates the biogenesis of its intronic miRNAs miR-200c and miR-141, but also protects miR-200c from target-directed miRNA degradation (TDMD) through direct binding to miR-200c. Our studies reveal a landscape of a subtype-specific lncRNA regulatory network, providing clinically relevant biological insights towards MSS/EMT GC.

CDH1 loss promotes diffuse-type gastric cancer tumorigenesis via epigenetic reprogramming and immune evasion

Diffuse-type gastric adenocarcinoma (DGAC) is a deadly cancer often diagnosed late and resistant to treatment. While hereditary DGAC is linked to CDH1 gene mutations, causing E-Cadherin loss, its role in sporadic DGAC is unclear. We discovered CDH1 inactivation in a subset of DGAC patient tumors. Analyzing single-cell transcriptomes in malignant ascites, we identified two DGAC subtypes: DGAC1 (CDH1 loss) and DGAC2 (lacking immune response). DGAC1 displayed distinct molecular signatures, activated DGAC-related pathways, and an abundance of exhausted T cells in ascites. Genetically engineered murine gastric organoids showed that Cdh1 knock-out (KO), KrasG12D, Trp53 KO (EKP) accelerates tumorigenesis with immune evasion compared to KrasG12D, Trp53 KO (KP). We also identified EZH2 as a key mediator promoting CDH1 loss-associated DGAC tumorigenesis. These findings highlight DGAC's molecular diversity and potential for personalized treatment in CDH1-inactivated patients.

Unique Genomic Alterations and Microbial Profiles Identified in Patients With Gastric Cancer of African, European, and Asian Ancestry: A Novel Path for Precision Oncology

OBJECTIVE

Here, we characterize differences in the genetic and microbial profiles of GC in patients of African (AFR), European, and Asian ancestry.

BACKGROUND

Gastric cancer (GC) is a heterogeneous disease with clinicopathologic variations due to a complex interplay of environmental and biological factors, which may affect disparities in oncologic outcomes..

METHODS

We identified 1042 patients with GC with next-generation sequencing data from an institutional Integrated Mutation Profiling of Actionable Cancer Targets assay and the Cancer Genomic Atlas group. Genetic ancestry was inferred from markers captured by the Integrated Mutation Profiling of Actionable Cancer Targets and the Cancer Genomic Atlas whole exome sequencing panels. Tumor microbial profiles were inferred from sequencing data using a validated microbiome bioinformatics pipeline. Genomic alterations and microbial profiles were compared among patients with GC of different ancestries.

RESULTS

We assessed 8023 genomic alterations. The most frequently altered genes were TP53 , ARID1A , KRAS , ERBB2 , and CDH1 . Patients of AFR ancestry had a significantly higher rate of CCNE1 alterations and a lower rate of KRAS alterations ( P < 0.05), and patients of East Asian ancestry had a significantly lower rate of PI3K pathway alterations ( P < 0.05) compared with other ancestries. Microbial diversity and enrichment did not differ significantly across ancestry groups ( P > 0.05).

CONCLUSIONS

Distinct patterns of genomic alterations and variations in microbial profiles were identified in patients with GC of AFR, European, and Asian ancestry. Our findings of variation in the prevalence of clinically actionable tumor alterations among ancestry groups suggest that precision medicine can mitigate oncologic disparities.

miRNA-381-3p Functions as a Tumor Suppressor to Inhibit Gastric Cancer by Targeting Fibroblast Growth Factor Receptor-2

Objectives: MicroRNAs possess essential effects on gastric cancer (GC), whereas the underlying mechanisms have not been fully uncovered. The present work focused on investigating the role of miR-381-3p in GC cellular processes and the possible mechanisms. Materials and Methods: miR-381-3p levels within GC tissues and cells were measured through quantitative real-time polymerase chain reaction (qRT-PCR). This study measured cell proliferation, apoptosis, and metastasis through EdU, colony formation, flow cytometry, and Transwell assays separately. TargetScan was adopted to predict the miR-381-3p targets, whereas luciferase reporter assay was adopted for confirmation. Results: miR-381-3p levels were decreased, whereas fibroblast growth factor receptor-2 (FGFR2) expression was increased in GC. miR-381-3p upregulation inhibited proliferation, migration, and invasion and it promoted the apoptosis of GC cells. Further, FGFR2 overexpression partly reversed the miR-381-3p-mediated impacts on GC cellular processes. Conclusions: This study provides an experimental basis, suggesting the potential of using miR-381-3p as the novel marker for GC. Clinical Trial Registration number: 2020-05.

Artificial Intelligence in the Pathology of Gastric Cancer

Recent advances in artificial intelligence (AI) have provided novel tools for rapid and precise pathologic diagnosis. The introduction of digital pathology has enabled the acquisition of scanned slide images that are essential for the application of AI. The application of AI for improved pathologic diagnosis includes the error-free detection of potentially negligible lesions, such as a minute focus of metastatic tumor cells in lymph nodes, the accurate diagnosis of potentially controversial histologic findings, such as very well-differentiated carcinomas mimicking normal epithelial tissues, and the pathological subtyping of the cancers. Additionally, the utilization of AI algorithms enables the precise decision of the score of immunohistochemical markers for targeted therapies, such as human epidermal growth factor receptor 2 and programmed death-ligand 1. Studies have revealed that AI assistance can reduce the discordance of interpretation between pathologists and more accurately predict clinical outcomes. Several approaches have been employed to develop novel biomarkers from histologic images using AI. Moreover, AI-assisted analysis of the cancer microenvironment showed that the distribution of tumor-infiltrating lymphocytes was related to the response to the immune checkpoint inhibitor therapy, emphasizing its value as a biomarker. As numerous studies have demonstrated the significance of AI-assisted interpretation and biomarker development, the AI-based approach will advance diagnostic pathology.

Immunotherapy for advanced gastric cancer

Gastric cancer (GC) is believed to be the fifth most common cancer and the third most common cause of death worldwide. Treatment techniques include radiation, chemotherapy, gastrectomy, and targeted treatments are often employed. Some hopeful results from the development of GC immunotherapy have already changed treatment approaches. Along with previous combination medicines, new immunotherapies have been developed that target distinct molecules. Despite ongoing studies into the current therapeutic options and significant improvements in this field, the prognosis for the ailment is poor. Since there are few treatment options and a delay in detection, the illness actually advances, spreads, and metastasizes. The bulk of immunotherapies in use today rely on cytotoxic immune cells, monoclonal antibodies, and gene-transferred vaccines. Immune checkpoint inhibitors have become more popular. In this review, we sought to examine the viewpoint and development of several immunotherapy treatment modalities for advanced GC, as well as the clinical results thus far reported. Additionally, we outlined tumor immune escape and tumor immunosurveillance.

Risk stratification for predicting postoperative recurrence of gastric cancer by grade of venous invasion

BACKGROUND

Venous invasion (VI) in pathological examination of surgically resected gastric cancer (GC) may predict postoperative recurrence, but there are no objective criteria for VI grading.

METHODS

157 GC patients (pathological stages I 82, II 34, and III 41) who underwent surgery with curative intent were analyzed. VI was graded in pathological examination by elastica van Gieson staining based on the number of VIs per glass slide as follows: v0, 0; v1, 1-3; v2, 4-6; and v3, ≥ 7. Filling-type invasion in veins with a minor axis of ≥ 1 mm increased the grade by 1. The association of VI grade with prognosis was statistically analyzed.

RESULTS

Recurrence increased with VI grade (v0 1.5%, v1 29.6%, v2 41.7%, v3 78.6%). VI grade as well as pathological (p) tumor, node, metastasis (TNM) stage was a significant recurrence predictor by the multivariate Cox analysis. VI grade was implicated in hematogenous and peritoneal recurrences independent of pTNM stage but not in nodal recurrence. GC was then divided into two tiers, without indication of adjuvant chemotherapy (AC) (pStage I, pT1 and pT3N0) and with AC indication (pStages remaining II/III), based on the ACTS-GC trial, which is common in Japan and East Asia. VI grade was a significant recurrence predictor in both tiers. v2/v3 revealed a significantly worse recurrence-free survival (RFS) than v0/v1 in GC without AC indication. v0/v1 exhibited RFS rate exceeding 95% even after 5 years but that of v2/v3 fell around 70% within one year postoperatively, suggesting that AC may be considered for this tier with v2/v3. GC with AC indication exhibited dismal RFS according to the VI grade. RFS rate fell below 80% within one year postoperatively when VI was positive, while recurrence was not observed in v0, which was, however, rare in this tier (10.9%). Differentiation grade did not significantly affect postoperative prognosis in both tiers.

CONCLUSIONS

VI grade was a significant predictor of postoperative GC recurrence irrespective of the AC indication based on the ACTS-GC study and this VI grading system could be applied in future studies of adjuvant therapy in GC presently deemed without AC indication in Japan.

The Impact of Venous Invasion on the Postoperative Recurrence of pT1-3N0cM0 Gastric Cancer

The impact of venous invasion (VI) on postoperative recurrence in pathological (p)T1-3N0 clinical (c)M0 gastric cancer (GC) remains unclear. We investigated the association of VI grade with prognosis in 94 (78 stage I and 16 stage IIA) patients. VI was graded during pathological examinations based on the number of VIs per glass slide as follows: v0, 0; v1, 1-3; v2, 4-6; and v3, ≥7. Filling-type invasion in veins with a minor axis of ≥1 mm increased VI grade by 1. Four (4.3%) patients experienced recurrence. Recurrence increased with pT (pT1, 0.0%; pT2, 11.1%; pT3, 18.8%) and VI grade (v0, 0.0%; v1, 3.7%, v2, 14.3%; and v3, 40.0%). Recurrence was significantly more frequent in pT3 than pT1 and in v2 + v3 than v0 (p = 0.006 and 0.005, respectively). Kaplan-Meier curve analyses demonstrated a significant decrease in recurrence-free survival according to pT (p = 0.0021) and VI grade (p < 0.0001). Multivariate Cox analysis revealed a significant association of VI grade with recurrence (p = 0.049). These results suggest that VI grade is a potential recurrence predictor for pT1-3N0cM0 GC. No recurrence can be expected in cases with pT1 or VI grade v0. Adjuvant therapy might be considered for pT3 or VI grade v2 + v3.

Molecular markers as predictors of response to perioperative chemotherapy in locally advanced gastric cancer

Introduction. Perioperative FLOT chemotherapy has improved prognosis in patients with locally advanced resectable gastric cancer (GC). However, in 80 % of cases, the tumor is resistant to the therapy, resulting in unnecessary toxicity and delayed surgical treatment.

Aim. Evaluation of clinico-morphological patterns of microsatellite instability, HER2 gene amplification, changes in gene copy number and their relationship with the response to perioperative FLOT chemotherapy in patients with locally advanced resectable GC.

Materials and methods. The retrospective study included 185 patients. All tumor samples were assessed for HER2 and microsatellite instability status. Among all cases there were 45 patients with locally advanced T2–4N1–2 M0 GC, who underwent a total or subtotal gastrectomy with D2 lymphadenectomy and perioperative chemotherapy with FLOT. Microsatellite instability detection was performed using fragment analysis, HER2 gene amplification testing – fluorescent in situ hybridization. Also 19 patients were tested for copy number changes of the FGFR1, FGFR2, KRAS, MET, EGFR, CCND1, MYC genes using Multiplex ligation-dependent probe amplification. The endpoints were progression-free survival and objective response rate.

Results. Microsatellite instability was detected in 4.8 % (9/185) of GC cases. Microsatellite instability was associated with advanced age (p = 0.005), low grade of differentiation (p = 0.011), presence of tumor-infiltrating lymphocytes (p = 0.0004), and high preoperative CA 72–4 levels (p = 0.025). Prevalence of HER2 amplification was 7.5 % (14/185). It was associated with low grade of differentiation (p = 0.048) and metastasis in regional lymph nodes (p = 0.037). PFS in patients with HER2-positive (HER2 – human epidermal growth factor receptor 2) GC treated with perioperative FLOT chemotherapy (4/45) was significantly lower than in patients with HER2-negative GC: the median was 156 and 317 days, respectively (hazard ratio 0.49; 95 % confidence interval 0.16–1.47; p = 0.0006). There was no correlation between the presence of the alteration and ORR (p = 1.0). Progression-free survival in GC patients with KRAS amplification (3/19) was significantly lower comparing with patients without it: the median was 98 and 327 days, respectively (hazard ratio 0.29; 95 % confidence interval 0.07–1.19; p <0.0001). There was no association between an increase in KRAS copy number and objective response rate (p = 1.0). For microsatellite instability and other studied markers no statistically significant correlation with progression-free survival and objective response rate was found (p >0.05).

Conclusion. The presence of HER2 and KRAS amplification have been shown as promising predictive markers of the treatment failure in patients treated with perioperative FLOT chemotherapy for locally advanced resectable GC.

Network-Based and Machine-Learning Approaches Identify Diagnostic and Prognostic Models for EMT-Type Gastric Tumors

The microsatellite stable/epithelial-mesenchymal transition (MSS/EMT) subtype of gastric cancer represents a highly aggressive class of tumors associated with low rates of survival and considerably high probabilities of recurrence. In the era of precision medicine, the accurate and prompt diagnosis of tumors of this subtype is of vital importance. In this study, we used Weighted Gene Co-expression Network Analysis (WGCNA) to identify a differentially expressed co-expression module of mRNAs in EMT-type gastric tumors. Using network analysis and linear discriminant analysis, we identified mRNA motifs and microRNA-based models with strong prognostic and diagnostic relevance: three models comprised of (i) the microRNAs miR-199a-5p and miR-141-3p, (ii) EVC/EVC2/GLI3, and (iii) PDE2A/GUCY1A1/GUCY1B1 gene expression profiles distinguish EMT-type tumors from other gastric tumors with high accuracy (Area Under the Receiver Operating Characteristic Curve (AUC) = 0.995, AUC = 0.9742, and AUC = 0.9717; respectively). Additionally, the DMD/ITGA1/CAV1 motif was identified as the top motif with consistent relevance to prognosis (hazard ratio > 3). Molecular functions of the members of the identified models highlight the central roles of MAPK, Hh, and cGMP/cAMP signaling in the pathology of the EMT subtype of gastric cancer and underscore their potential utility in precision therapeutic approaches.

Somatic Mutational Landscape in Mexican Patients: CDH1 Mutations and chr20q13.33 Amplifications Are Associated with Diffuse-Type Gastric Adenocarcinoma

The Hispanic population, compared with other ethnic groups, presents a more aggressive gastric cancer phenotype with higher frequency of diffuse-type gastric adenocarcinoma (GA); this could be related to the mutational landscape of GA in these patients. Using whole-exome sequencing, we sought to present the mutational landscape of GA from 50 Mexican patients who were treated at The Instituto Nacional de Cancerología from 2019 to 2020. We performed a comprehensive statistical analysis to explore the relationship of the genomic variants and clinical data such as tumor histology and presence of signet-ring cell, H. pylori, and EBV. We describe a potentially different mutational landscape between diffuse and intestinal GA in Mexican patients. Patients with intestinal-type GA tended to present a higher frequency of NOTCH1 mutations, copy number gains in cytobands 13.14, 10q23.33, and 12q25.1, and copy number losses in cytobands 7p12, 14q24.2, and 11q13.1; whereas patients with diffuse-type GA tended to present a high frequency of CDH1 mutations and CNV gains in cytobands 20q13.33 and 22q11.21. This is the first description of a mutational landscape of GA in Mexican patients to better understand tumorigenesis in Hispanic patients and lay the groundwork for discovering potential biomarkers and therapeutic targets.

Diagnostic laparoscopy is underutilized in the staging of gastric adenocarcinoma regardless of hospital type: An US safety net collaborative analysis

BACKGROUND

Diagnostic laparoscopy (DL) is a key component of staging for locally advanced gastric adenocarcinoma (GA). We hypothesized that utilization of DL varied between safety net (SNH) and affiliated tertiary referral centers (TRCs).

METHODS

Patients diagnosed with primary GA eligible for DL were identified from the US Safety Net Collaborative database (2012-2014). Clinicopathologic factors were analyzed for association with use of DL and findings on DL. Overall survival (OS) was analyzed by Kaplan-Meier method.

RESULTS

Among 233 eligible patients, 69 (30%) received DL, of which 24 (35%) were positive for metastatic disease. Forty percent of eligible SNH patients underwent DL compared to 21.5% at TRCs. Lack of insurance was significantly associated with decreased use of DL (OR 0.48, p < 0.01), while African American (OR 6.87, p = 0.02) and Asian race (OR 3.12, p ≤ 0.01), signet ring cells on biopsy (OR 3.14, p < 0.01), and distal tumors (OR 1.62, p < 0.01) were associated with increased use. Median OS of patients with a negative DL was better than those without DL or a positive DL (not reached vs. 32 vs. 12 months, p < 0.005, Figure 1).

CONCLUSIONS

Results from DL are a strong predictor of OS in GA; however, the procedure is underutilized. Patients from racial minority groups were more likely to undergo DL, which likely accounts for higher DL rates among SNH patients.

Practical Considerations in Diagnosing and Managing Early-Onset GI Cancers

The incidence of early-onset (EO) GI cancers occurring in individuals younger than age 50 years has been rising at an alarming rate over the past two decades. Although this rise in incidence among young patients correlates with increased rates of obesity, changes in diet, and alterations in the environment, the effects of these environmental factors on carcinogenesis, metastasis, and treatment response are unknown. Although several unique clinical trends exist among EO-GI cancers and their average-onset GI cancer counterparts, GI cancers are molecularly indistinct between younger and older patients, and no data support distinct treatment paradigms for patients with EO disease. The majority of EO-GI cancers are not explained by germline changes. There remains a critical need for further research to understand the pathogenesis and optimal management of EO-GI cancers. In addition, current screening strategies are not adequate to identify EO-GI cancers, and early biomarkers are needed. Specialized centers, with a focus on psychosocial aspects of cancer management, can address the unique care needs of patients with EO-GI cancers.

LncRNA PVT1 Promotes Cell Proliferation, Invasion, and Migration and Inhibits Cell Apoptosis by Phosphorylating YAP

Gastric cancer (GC) as a serious global health problem is a threat to human longevity. Plasmacytoma variant translocation 1 (PVT1) participates in the formation and progression of various cancers, including GC. The aim of this study is to investigate the mechanism underlying the functions of PVT1 and explore a novel target for the diagnosis and treatment of GC. Analysis of the TCGA dataset using the R software identified that the lncRNA PVT1 was greatly upregulated in GC tissues. Twenty pairs of GC and adjacent normal tissues were acquired from patients with GC, and the expression of PVT1 was evaluated using RT-qPCR. Furthermore, PVT1 expression was knocked down in GC cells using siRNA, and the GC cells were divided into control, negative control (NC), and siRNA groups. Cell proliferation ability was analyzed using Cell Counting Kit-8 (CCK8) and colony formation assays, whereas cell migration and invasion ability were investigated through wound healing and Transwell assays. Moreover, Western blotting was used to analyze the expression of Yes-associated protein (YAP) and epithelial-to-mesenchymal transition (EMT) proteins. We also found that PVT1 and YAP expressions were upregulated in the GC tissues compared with those in the adjacent nontumor tissues. Knockdown of PVT1 was found to inhibit the proliferation, invasion, and migration and promote apoptosis of GC cells. Furthermore, knockdown of PVT1 downregulated YAP and promoted phosphorylation of YAP, suggesting that PVT1 exerts actions on GC cells by targeting YAP and inhibits cell apoptosis in vitro. The EMT process was also inhibited by the knockdown of PVT1. In summary, lncRNA PVT1 facilitated cell proliferation, invasion, and migration and suppressed cell apoptosis by targeting YAP. This study suggests that the expressions of PVT1 and YAP could be used for the early detection of GC and the occurrence and development of GC could be inhibited by interfering the interaction of PVT1 and YAP, which will provide new insights for the diagnosis, treatment, and prognosis of GC.

Expression of miR-4739 in Gastric cancer and its Relationship with Clinical Pathological Features of Patients

Objective

To investigate the expression level of miR-4739 in gastric cancer (GC), analyze its diagnostic value in GC and the relationship with clinical pathological characteristics, and analyze its impact on the prognosis of patients.

Methods

A total of 96 patients with GC who underwent radical gastrectomy in our hospital from March 2017 to June 2021 were selected. GC tissues from all patients were collected, and normal tissues adjacent to cancer were collected as controls. The expression level of miR-4739 in tissues was detected, the relationship between miR-4739 and different pathological features was analyzed, and the diagnostic value of miR-4739 in GC was analyzed. All patients were followed up after the operation, and the survival time of the patients was set as from the day of the first operation to 1 d when the patients died or the follow-up ended.

Results

The relative expression level of miR-4739 in the GC tissue was (0.39 ± 0.06), lower than that in the paracancerous tissue (1.18 ± 0.19) (P < 0.05). The AUC of miR-4739 in the diagnosis of GC was 0.705. When the Youden index was 0.320 and the optimal cutoff value was 0.37, the sensitivity was 95.30% and the specificity was 36.70%. The expression level of miR-4739 in our patient was related to the differentiation degree, lymph node metastasis, tumor diameter, and TNM stage (P < 0.05). During the follow-up period, 26 of 96 patients died, and the survival rate was 72.92% (26/96). The median survival time was 29 months in the miR-4739 LE group, which was shorter than 39 months in the miR-4739 HE group (P < 0.05). Univariate analysis showed that age, degree of differentiation, lymph node metastasis, tumor diameter, TNM staging, and miR-4739 expression were all related to the prognosis of the patient (P < 0.05). Multivariate analysis showed that differentiation degree, lymph node metastasis, tumor diameter, TNM staging, and miR-4739 expression were all independent factors affecting the prognosis of the patients (P < 0.05).

Conclusion

The expression of miR-4739 in GC tissue was down-regulated, and its level was related to the degree of differentiation, lymph node metastasis, tumor diameter, and TNM stage. The expression level of miR-4739 has certain diagnostic value for patients with GC, and the prognosis of patients in LE group was worse than that in HE group.

Lenvatinib inhibits the growth of gastric cancer patient-derived xenografts generated from a heterogeneous population

BACKGROUND

Lenvatinib is a multitargeted tyrosine kinase inhibitor that is being tested in combination with immune checkpoint inhibitors to treat advanced gastric cancer; however, little data exists regarding the efficacy of lenvatinib monotherapy. Patient-derived xenografts (PDX) are established by engrafting human tumors into immunodeficient mice. The generation of PDXs may be hampered by growth of lymphomas. In this study, we compared the use of mice with different degrees of immunodeficiency to establish PDXs from a diverse cohort of Western gastric cancer patients. We then tested the efficacy of lenvatinib in this system.

METHODS

PDXs were established by implanting gastric cancer tissue into NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) or Foxn1nu (nude) mice. Tumors from multiple passages from each PDX line were compared histologically and transcriptomically. PDX-bearing mice were randomized to receive the drug delivery vehicle or lenvatinib. After 21 days, the percent tumor volume change (%Δvtumor) was calculated.

RESULTS

23 PDX models were established from Black, non-Hispanic White, Hispanic, and Asian gastric cancer patients. The engraftment rate was 17% (23/139). Tumors implanted into NSG (16%; 18/115) and nude (21%; 5/24) mice had a similar engraftment rate. The rate of lymphoma formation in nude mice (0%; 0/24) was lower than in NSG mice (20%; 23/115; p < 0.05). PDXs derived using both strains maintained histologic and gene expression profiles across passages. Lenvatinib treatment (mean %Δvtumor: -33%) significantly reduced tumor growth as compared to vehicle treatment (mean %Δvtumor: 190%; p < 0.0001).

CONCLUSIONS

Nude mice are a superior platform than NSG mice for generating PDXs from gastric cancer patients. Lenvatinib showed promising antitumor activity in PDXs established from a diverse Western patient population and warrants further investigation in gastric cancer.

Met–HER3 crosstalk supports proliferation via MPZL3 in MET-amplified cancer cells

Receptor tyrosine kinases (RTKs) are recognized as targets of precision medicine in human cancer upon their gene amplification or constitutive activation, resulting in increased downstream signal complexity including heterotypic crosstalk with other RTKs. The Met RTK exhibits such reciprocal crosstalk with several members of the human EGFR (HER) family of RTKs when amplified in cancer cells. We show that Met signaling converges on HER3–tyrosine phosphorylation across a panel of seven MET-amplified cancer cell lines and that HER3 is required for cancer cell expansion and oncogenic capacity in vitro and in vivo. Gene expression analysis of HER3-depleted cells identified MPZL3, encoding a single-pass transmembrane protein, as HER3-dependent effector in multiple MET-amplified cancer cell lines. MPZL3 interacts with HER3 and MPZL3 loss phenocopies HER3 loss in MET-amplified cells, while MPZL3 overexpression can partially rescue proliferation upon HER3 depletion. Together, these data support an oncogenic role for a HER3–MPZL3 axis in MET-amplified cancers.

Nativity Status is an Important Social Determinant of Health for Hispanic Patients with Gastric Cancer in Texas

BACKGROUND

The U.S. foreign-born population is rapidly increasing, and cancer incidence/mortality rates have been shown to differ by nativity status. Our study aimed to characterize differences in gastric cancer presentation and survival among Hispanic patients in Texas by nativity status.

METHODS

We conducted a retrospective review of the Texas Cancer Registry to identify Hispanic patients diagnosed with gastric adenocarcinoma between 2004 and 2017. Existing indices applied to 2010 census tract-level data were utilized to measure neighborhood socioeconomic status (nSES) and Hispanic enclaves. Nativity status was imputed for patients with missing data. Multivariable Cox proportional hazard models were fit for overall survival adjusted for age, insurance status, diagnosis year, tumor location, stage, grade, reporting source, nativity status, nSES, and Hispanic enclave.

RESULTS

Our study cohort consisted of 6186 patients and 39% were foreign-born. A greater proportion of foreign-born patients were diagnosed at < 45 years old (16% vs. 11%, p < 0.0001) and had metastatic disease at presentation (47% vs. 34%, p < 0.0001). Foreign-born patients were more often uninsured, in the lowest nSES quintile, and the highest (most ethnically distinct) quintile for Hispanic enclave. Stage-specific overall survival was significantly higher among foreign-born patients. In our multivariate model, foreign-born Hispanic patients had improved survival versus US-born (hazard ratio [HR] 0.90, 95% confidence interval [CI] 0.82-0.99).

CONCLUSIONS

The clinical presentation of gastric cancer differs significantly between foreign-born and U.S.-born Hispanic patients. Foreign-born Hispanic patients have improved survival after adjusting for socioeconomic, neighborhood, and clinical factors. Further studies are needed to identify specific causal mechanisms driving the observed survival difference by nativity status.

Prediction and prognostic significance of ALOX12B and PACSIN1 expression in gastric cancer by genome-wide RNA expression and methylation analysis

Background

Stomach adenocarcinoma (STAD) is one of the common gastrointestinal cancers, characterized by late discovery and metastasis. However, research of gene methylation and expression in gastric cancer (GC) metastasis has been quite limited. This study aimed to investigate the altered gene expression patterns between metastasis and non-metastasis samples using high-throughput RNA and methylation profiles from a large number of patients. Another aim was to identify a specific potential metastasis biomarker, with the ability to predict the metastasis possibility and prognosis of patients with STAD.

Methods

In this study, we integrated The Cancer Genome Atlas (TCGA) program STAD datasets, analyzed the RNA expression and DNA methylation data between non-metastasis (M0) and distant metastasis (M1) samples, and evaluated the candidate biomarker in survival and prognosis of GC.

Results

Among all patients enrolled, 329 with M0 and M1 information were positive for RNA analysis, and 353 with M0 and M1 information were positive for methylation analysis. We found 29 upregulated and 200 downregulated genes in RNA level, and 5,046 hypermethylated and 8,563 hypomethylated probes in methylation level. Among these genes, we found high RNA expression level and low DNA methylation level of ALOX12B and PACSIN1 in GC metastasis samples. Patients with high expression of these 2 genes had poor overall survival (OS), progression-free survival (PFS), and post-progression survival (PPS).

Conclusions

The expression levels of ALOX12B and PACSIN1 were higher in the metastasis than non-metastasis group, and participants with high expression of these 2 genes were found to have poor survival. The genes ALOX12B and PACSIN1 are potential biomarkers of metastasis and poor prognosis, especially in early stage GC, and provide additional information for subsequent comprehensive treatment of GC.

The Upregulation of PLXDC2 Correlates with Immune Microenvironment Characteristics and Predicts Prognosis in Gastric Cancer

Tumor microenvironment (TME) has been demonstrated to exhibit a regulatory effect on the progressions of gastric cancer (GC). However, the related functions of stromal and immune components (TME-associated genes) in TME remain largely unclear. From the TCGA dataset, we downloaded the clinical data of 375 GC cases and then estimated the percentage of tumor-infiltrating immunocytes (TICs) and the levels of immune and stromal constituents by the use of CIBERSORT and ESTIMATE tolls. Univariate assays were applied to study the differentially expressed genes. The associations between the clinical information of GC patients and the expressions of the specific genes were analyzed based on the TCGA datasets. The effect of Plexin domain containing 2 (PLXDC2) expression on TICs was conducted. We observed that PLXDC2 expression was distinctly upregulated in GC specimens compared with nontumor gastric specimens. Its upregulation was associated with advanced clinical stages and predicted a shorter overall survival of GC patients. The genes in the group of higher expressing PLXDC2 were primarily enriched in immunity-associated events. By the use of CIBERSORT, we observed that PLXDC2 expressions were related to the proportion of dendritic cells resting, T cell CD4 memory resting, eosinophils, mastocyte resting, mononuclear cells, plasma cells, T cell follicle helper, macrophage M2, and dendritic cells activated. Overall, our discoveries revealed that the expression of PLXDC2 was remarkable in GC, might be a possible biomarker for GC, and provided novel contents regarding immune infiltrates, offering novel insight for treatments of GC.

Pathologic Lymph Node Staging of Gastric Cancer

OBJECTIVES

The TNM classification is the main tool for lymph node (LN) staging in gastric cancer (GC). However, alternative LN staging systems have been proposed, and the role of features other than the number of metastatic LNs is being investigated. Our aim is to discuss the main challenges of LN assessment in GC.

METHODS

Comprehensive review of the literature on alternative LN staging systems, examined LNs, sentinel LN (SLN) biopsy, LN micrometastases (LNMIs), extracapsular extension (ECE), and tumor deposits (TDs) in GC.

RESULTS

Many controversies exist regarding LN assessment in GC. The TNM classification shows excellent prognostic performance, but alternative prognostic methods such as the LN ratio or log odds of positive LNs have demonstrated to be better than the TNM system in terms of prognostic accuracy. The value of SLN biopsy and LNMIs in GC is still unclear, and several challenges concerning their clinical impact and pathologic analysis must be overcome before their introduction in clinical practice. Most authors have identified ECE and TDs as independent prognostic factors for survival in GC.

CONCLUSIONS

Further studies should be performed to evaluate the impact of these features on the TNM classification and patient outcomes, as well as to standardize alternative LN staging systems.

MiR-1224 Acts as a Prognostic Biomarker and Inhibits the Progression of Gastric Cancer by Targeting SATB1

Objective

MiR-1224 has been reported to exhibit abnormal expression in several tumors. However, the expressing pattern and roles of miR-1224 in gastric cancer (GC) remain unclear. Our current research aimed to explore the potential involvement of miR-1224 in the GC progression.

Materials and Methods

The expression of miR-1224 was examined in tissue samples of 128 GC patients and cell lines by RT-PCR. Besides, the associations of miR-1224 expressions with clinicopathologic features and prognosis of GC patients were analyzed. Then, the possible influences of miR-1224 on cell proliferation and cell migration were determined. Afterward, the molecular target of miR-1224 was identified using bioinformatics assays and confirmed experimentally. Finally, RT-PCR and Western blot assays were performed to investigate the effect of the abnormal miR-1224 expression on the EMT and Wnt/β-catenin pathway.

Results

miR-1224 was lowly expressed in the GC specimens and cell lines due to T classification and TNM stage. Survival assays demonstrated that GC patients with low expressions of miR-1224 possessed poor overall survivals. Moreover, in vitro and in vivo assays revealed that the overexpression of miR-1224 inhibited cell proliferation, migration, and invasion in GC cells. SATB homeobox 1 (SATB1) was verified as a direct target of miR-1224 in GC. Furthermore, β-catenin and c-myc were significantly inhibited in miR-1224-overexpression cells.

Conclusions

Our findings highlight the potential of miR-1224 as a therapeutic target and novel biomarker for GC patients

Clinical Presentation Patterns and Survival Outcomes of Hispanic Patients with Gastric Cancer

BACKGROUND

Hispanic patients have a higher incidence of gastric cancer when compared to non-Hispanics. Outlining clinicodemographic characteristics and assessing the impact of ethnicity on stage-specific survival may identify opportunities to improve gastric cancer care for this population.

METHODS

Patients with gastric cancer in the US Safety Net Collaborative (2012-2014) were retrospectively reviewed. Demographics, clinicopathologic characteristics, operative details, and outcomes were compared between Hispanic and non-Hispanic patients. Early onset gastric cancer was defined as age <50 years. Kaplan-Meier and Cox proportional-hazards models were used to identify the impact of ethnicity on disease-specific survival (DSS).

RESULTS

Seven hundred and ninety-seven patients were included, of which 219 (28%) were Hispanic. Hispanic patients were more likely to seek care at safety-net hospitals (66 vs 39%) and be uninsured (36 vs 17%), and less likely to have a primary care provider (PCP) (46 vs 75%; all P<0.05). Hispanic patients were twice as likely to present with early onset gastric cancer (28 vs 15%) and were more frequently diagnosed in the emergency room (54 vs 37%) with both abdominal pain and weight loss (44 vs 31%; all P <0.05). Treatment paradigms, operative outcomes, and DSS were similar between Hispanic and non-Hispanic patients when accounting for cancer stage. Cancer stage, pathologically positive nodes, and negative surgical margins were independently associated with DSS.

CONCLUSIONS

A diagnosis of gastric cancer must be considered in previously healthy Hispanic patients who present to the emergency room with both abdominal pain and weight loss. Fewer than 50% of Hispanic patients have a PCP, indicating poor outpatient support. Efforts to improve outpatient support and screening may improve gastric cancer outcomes in this vulnerable population.

Combined Simplified Molecular Classification of Gastric Adenocarcinoma, Enhanced by Lymph Node Status: An Integrative Approach

Simple Summary

In this study, we present a simple but comprehensive molecular analysis of gastric carcinoma. The two major existing classification schemes show some discrepancies and are highly technically demanding, which makes them hardly feasible in daily diagnostic routines. Our workflow is based on simple and commercially available technology and provides a potential consensus approach by integrating the two major classification schemes. Furthermore, our approach allows the molecular subtypes to be assigned to different prognostic groups. We are convinced that our approach may help to better understand the molecular mechanisms of this worldwide health burden and that it could pave the way for new therapeutic targets.

Abstract

Gastric adenocarcinoma (GAC) is a heterogeneous disease and at least two major studies have recently provided a molecular classification for this tumor: The Cancer Genome Atlas (TCGA) and the Asian Cancer Research Group (ARCG). Both classifications quote four molecular subtypes, but these subtypes only partially overlap. In addition, the classifications are based on complex and cost-intensive technologies, which are hardly feasible for everyday practice. Therefore, simplified approaches using immunohistochemistry (IHC), in situ hybridization (ISH) as well as commercially available next generation sequencing (NGS) have been considered for routine use. In the present study, we screened 115 GAC by IHC for p53, MutL Homolog 1 (MLH1) and E-cadherin and performed ISH for Epstein–Barr virus (EBV). In addition, sequencing by NGS for TP53 and tumor associated genes was performed. With this approach, we were able to define five subtypes of GAC: (1) Microsatellite Instable (MSI), (2) EBV-associated, (3) Epithelial Mesenchymal Transition (EMT)-like, (4) p53 aberrant tumors surrogating for chromosomal instability and (5) p53 proficient tumors surrogating for genomics stable cancers. Furthermore, by considering lymph node metastasis in the p53 aberrant GAC, a better prognostic stratification was achieved which finally allowed us to separate the GAC highly significant in a group with poor and good-to-intermediate prognosis, respectively. Our data show that molecular classification of GAC can be achieved by using commercially available assays including IHC, ISH and NGS. Furthermore, we present an integrative workflow, which has the potential to overcome the uncertainty resulting from discrepancies from existing classification schemes.

Development of a simplified tumor-lymph node ratio classification system for patients with resected gastric cancer: A western study

INTRODUCTION

Gastric cancer (GC) shows high recurrence and mortality rates. The AJCC TNM staging system is the best prognostic predictor, but lymph node assessment is a major source of controversy. Recent studies have found that lymph node ratio (LNR) may overcome TNM limitations. Our aim is to develop a simplified tumor-LNR (T-LNR) classification for predicting prognosis of resected GC.

METHODS

Retrospective study of all GC resected in a tertiary center in Spain (N = 377). Clinicopathological features were assessed, LNR was classified into N0:0%, N1:1-25%, N2:>25%, and a T-LNR classification was developed. Statistical analyses were performed.

RESULTS

317 patients were finally included. Most patients were male (54.6%) and mean age was 72 years. Tumors were intestinal (61%), diffuse (30.8%) or mixed (8.1%). During follow-up, 36.7% and 27.4% of patients progressed and died, respectively. T-LNR classification divided patients into five prognostic categories (S1-S5). Most cases were S1-S4 (26.2%, 19.9%, 22.6% and 23.6%, respectively). 7.6% of tumors were S5. T-LNR classification was significantly associated with tumor size, depth, macroscopical type, Laurén subtype, signet ring cells, histologic grade, lymphovascular invasion, perineural infiltration, infiltrative growth, patient progression and death. Kaplan-Meier curves for OS showed an excellent patient stratification with evenly spaced curves. As for DFS, T-LNR classification also showed good discriminatory ability with non-overlapping curves. T-LNR classification was independently related to both OS and DFS.

CONCLUSIONS

T-LNR classifications can successfully predict prognosis of GC patients. Larger studies in other geographic regions should be performed to refine this classification and to validate its prognostic relevance.

Cancer health disparities in racial/ethnic minorities in the United States

There are well-established disparities in cancer incidence and outcomes by race/ethnicity that result from the interplay between structural, socioeconomic, socio-environmental, behavioural and biological factors. However, large research studies designed to investigate factors contributing to cancer aetiology and progression have mainly focused on populations of European origin. The limitations in clinicopathological and genetic data, as well as the reduced availability of biospecimens from diverse populations, contribute to the knowledge gap and have the potential to widen cancer health disparities. In this review, we summarise reported disparities and associated factors in the United States of America (USA) for the most common cancers (breast, prostate, lung and colon), and for a subset of other cancers that highlight the complexity of disparities (gastric, liver, pancreas and leukaemia). We focus on populations commonly identified and referred to as racial/ethnic minorities in the USA-African Americans/Blacks, American Indians and Alaska Natives, Asians, Native Hawaiians/other Pacific Islanders and Hispanics/Latinos. We conclude that even though substantial progress has been made in understanding the factors underlying cancer health disparities, marked inequities persist. Additional efforts are needed to include participants from diverse populations in the research of cancer aetiology, biology and treatment. Furthermore, to eliminate cancer health disparities, it will be necessary to facilitate access to, and utilisation of, health services to all individuals, and to address structural inequities, including racism, that disproportionally affect racial/ethnic minorities in the USA.

Epigenetic Variation Analysis Leads to Biomarker Discovery in Gastric Adenocarcinoma

As one of the most common malignant tumors worldwide, gastric adenocarcinoma (GC) and its prognosis are still poorly understood. Various genetic and epigenetic factors have been indicated in GC carcinogenesis. However, a comprehensive and in-depth investigation of epigenetic alteration in gastric cancer is still missing. In this study, we systematically investigated some key epigenetic features in GC, including DNA methylation and five core histone modifications. Data from The Cancer Genome Atlas Program and other studies (Gene Expression Omnibus) were collected, analyzed, and validated with multivariate statistical analysis methods. The landscape of epi-modifications in gastric cancer was described. Chromatin state transition analysis showed a histone marker shift in gastric cancer genome by employing a Hidden-Markov-Model based approach, indicated that histone marks tend to label different sets of genes in GC compared to control. An additive effect of these epigenetic marks was observed by integrated analysis with gene expression data, suggesting epigenetic modifications may cooperatively regulate gene expression. However, the effect of DNA methylation was found more significant without the presence of the five histone modifications in our study. By constructing a PPI network, key genes to distinguish GC from normal samples were identified, and distinct patterns of oncogenic pathways in GC were revealed. Some of these genes can also serve as potential biomarkers to classify various GC molecular subtypes. Our results provide important insights into the epigenetic regulation in gastric cancer and other cancers in general. This study describes the aberrant epigenetic variation pattern in GC and provides potential direction for epigenetic biomarker discovery.

Genetic factors associated with cancer racial disparity - an integrative study across twenty-one cancer types

It is well known that different racial groups have significantly different incidence and mortality rates for certain cancers. It has been suggested that biological factors play a major role in these cancer racial disparities. Previous studies on the biological factors contributing to cancer racial disparity have generated a very large number of candidate factors, although there is modest agreement among the results of the different studies. Here, we performed an integrative analysis using genomic data of 21 cancer types from TCGA, GTEx, and the 1000 Genomes Project to identify biological factors contributing to racial disparity in cancer. We also built a companion website with additional results for cancer researchers to freely mine. Our study identified genes, gene families, and pathways displaying similar differential expression patterns between different racial groups across multiple cancer types. Among them, XKR9 gene expression was found to be significantly associated with overall survival for all cancers combined as well as for several individual cancers. Our results point to the interesting hypothesis that XKR9 could be a novel drug target for cancer immunotherapy. Bayesian network modeling showed that XKR9 is linked to important cancer-related genes, including FOXM1, cyclin B1, and RB1CC1 (RB1 regulator). In addition, metabolic pathways, neural signaling pathways, and several cancer-related gene families were found to be significantly associated with cancer racial disparities for multiple cancer types. Single nucleotide polymorphisms (SNPs) discovered through integrating data from the TCGA, GTEx, and 1000 Genomes databases provide biologists the opportunity to test highly promising, targeted hypotheses to gain a deeper understanding of the genetic drivers of cancer racial disparity and cancer biology in general.

Diffuse gastric cancer: histologic, molecular, and genetic basis of disease

Diffuse gastric cancer (DGC) is a distinct histopathologic and molecular disease, characterized by mutations in CDH1, RHOA, and others. In addition, DGC is associated with familial syndromes, including hereditary DGC and germline mutation in CDH1. Clinically, this subtype of gastric adenocarcinoma is associated with a poor prognosis and possible resistance to available systemic therapies. An understanding of the genetic and molecular underpinnings of DGC may help inform of its clinical behavior and aid in screening, diagnosis, and response to treatment. In this review, we will review the current histologic, molecular, and genetic landscape of DGC and its relevance to clinical practice.

Peritoneal carcinomatosis in gastric cancer: Are Hispanics at higher risk?

BACKGROUND

A recent study from our group identified Hispanic race/ethnicity as an independent predictor of peritoneal carcinomatosis (PC) in gastric cancer. We sought to identify the tumor factors that might contribute to this strong association in Hispanics.

METHODS

California Cancer Registry data were used to identify patients diagnosed with gastric adenocarcinoma from 2004 to 2014. Logistic regression analyses were performed to determine odds ratios for cancer stage, tumor location, grade, histology, and PC.

RESULTS

Of 16,275 patients with gastric adenocarcinoma who met inclusion criteria, 6463 (39.7%) were non-Hispanic White (NHW), 4953 (30.4%) were Hispanic, 1020 (6.3%) were non-Hispanic Black (NHB), and 3915 (23.6%) were Asian/other. Compared to NHW, Hispanics were more likely to have a poorly differentiated grade (65.9% vs. 57.6%; p < .001), signet ring adenocarcinoma (28.1% vs. 17.6%; p < .001) and stage IV (51.9% vs. 45.0%; p < .001) gastric cancer. The proportion of stage IV patients with PC was also significantly higher in Hispanics compared to NHW, NHB, and Asian/other (28.5% vs. 16.6%, 20.5%, and 25.2%, respectively; p < .001).

CONCLUSIONS

Hispanic ethnicity is an independent predictor of aggressive tumor phenotype and PC. Disproportionate incidence of signet ring adenocarcinoma and PC highlight the need to explore the genomic differences in Hispanic gastric cancer.

Disadvantages for non-Hispanic whites in gastric carcinoma survival in Florida

PURPOSE

The prognosis for gastric carcinoma (GC) remains challenging with less than 35% of patients surviving 5 years. GC survival varies greatly by anatomical site, cardia and non-cardia. However, these important differences have not been thoroughly studied in relation to the increasing diversity in US populations such as Florida. In this study we examined, for the first time, the effect of race-ethnicity on risk of death from GC controlling for potential risk factors separately for cardia and non-cardia GCs.

METHODS

Data on GCs diagnosed in Florida from 2005-2016 were obtained from the statewide cancer registry. Age-standardized GC-specific 5-year survival was computed by anatomical site and race-ethnicity. In addition, a competing risk analysis was performed to assess prognostic factors and to estimate subdistribution hazard ratios of death from GC.

RESULTS

Whites had high proportions of cardia GC (43.9%) compared to all racial/ethnic minorities (10.9%, 19.6%, and 13.8% in Blacks, Hispanics, and Asians, respectively; p < .0001). Among 12,302 cases included, there were 7534 deaths from GC and 1179 from other causes. Age standardized GC-specific 5-year survival was significantly lower for Whites (28.0%) compared to Blacks (31.6%), Hispanics (37.6%), and Asians, (39.6%) and significantly lower for cardia GC (25.0%, 95% CI 23.4-26.6) compared to non-cardia GC (37.0%, 95% CI 35.5-38.4). Multivariable competing risk analysis in patients with non-cardia GC showed that Asians (sHR: 0.64, 95% CI 0.51-0.80), Hispanics (sHR 0.71, 95% CI 0.64-0.78), and Blacks (sHR 0.83, 95% CI 0.75-0.92) all had lower risks of death from GC compared to Whites. In patients with cardia GC, only Hispanics had statistically significant lower risk of death from GC than Whites (sHR 0.84, 95% CI 0.74-0.95, p = 0.005).

CONCLUSIONS

The study of racial/ethnic survival disparities in patients with GC in Florida reveals Whites as the most disadvantaged group. Whites are more afflicted by cardia GC, which is associated with higher risk of death than non-cardia GC. However, even within non-cardia GC, Whites had higher risk of death than the other racial-ethnic groups. Commonly assessed survival determinants do not adequately explain these unusual disparities; thus, further investigation is warranted.

Recent Developments of Systemic Chemotherapy for Gastric Cancer

Gastric cancer (GC) is a molecularly heterogeneous disease. Its molecular background, epidemiology, and standard of care are quite different between Eastern and Western countries. Many efforts have been made in developing more effective surgeries and adjuvant chemotherapies for resectable GC in each region. Recently, an intensive combination of cytotoxic agents has been established as a new standard of adjuvant treatment. Meanwhile, palliative chemotherapy is a uniform standard treatment for unresectable GC worldwide. Recently, one of the most remarkable advances in therapy for unresectable GC has been the approval of immune checkpoint inhibitors (ICIs). The use of ICIs as frontline treatment is currently being investigated. In addition, novel combinations of ICIs and targeted drugs are being evaluated in clinical trials. Despite these advances, the complex biology of GC has resulted in the failure of targeted therapies, with the exceptions of HER2-targeted trastuzumab and VEGFR2-targeted ramucirumab. GC harbors many redundant oncogenic pathways, and small subsets of tumors are driven by different specific pathways. Therefore, a combination strategy simultaneously inhibiting several pathways and/or stricter patient selection for better response to targeted drugs are needed to improve clinical outcomes in this field.

Genomics and Targeted Therapies in Gastroesophageal Adenocarcinoma

Gastroesophageal adenocarcinomas (GEA) are devastating diseases with stark global presence. Over the past 10 years, there have been minimal improvements in treatment approach despite numerous clinical trials. Here, we review recent progress toward understanding the molecular features of these cancers and the diagnostic and therapeutic challenges posed by their intrinsic genomic instability and heterogeneity. We highlight the potential of genomic heterogeneity to influence clinical trial outcomes for targeted therapies and emphasize the need for comprehensive molecular profiling to guide treatment selection and adapt treatment to resistance and genomic evolution. Revising our clinical approach to GEA by leveraging genomic advances will be integral to the success of current and future treatments, especially as novel targets become therapeutically tractable. SIGNIFICANCE: GEAs are deadly cancers with few treatment options. Characterization of the genomic landscape of these cancers has revealed considerable genetic diversity and spatial heterogeneity. Understanding these fundamental properties of GEA will be critical for overcoming barriers to the development of novel, more effective therapeutic strategies.

Multidisciplinary management of stage II-III gastric and gastro-oesophageal junction cancer

The aim of this manuscript is to discuss the viewpoint of the European Organisation for Research and Treatment of Cancer (EORTC) Gastric Cancer Taskforce and Japan Clinical Oncology Group (JCOG) Gastric Cancer Study Group on the current challenges in the multidisciplinary management of stage II-III gastric and gastro-oesophageal junction (GEJ) cancer. We seek to outline how these challenges are addressed in current trials of both groups. Key elements of future trials of EORTC and JCOG in this indication are described, and a joint vision on how multidisciplinary research of gastric and GEJ cancer patients should be organised is outlined.

LncRNA LINC00470 promotes the degradation of PTEN mRNA to facilitate malignant behavior in gastric cancer cells

Gastric cancer (GC) is the fourth most frequent malignancy worldwide. Recently, long noncoding RNA (lncRNA) LINC00470 has been demonstrated to play an oncogenic role in human cancer. However, the clinical significance and functional role of LINC00470 in the progression of GC is largely unknown. In this study, our findings showed that LINC00470 was significantly upregulated in GC tissues and cell lines, and correlated with distant metastasis, TNM stage and poor prognosis. Overexpression and knockdown experiments revealed its oncogenic functions on GC cell proliferation, migration and invasion. Mechanistically, LINC00470 associated with PTEN mRNA and suppressed its stability through interaction with the N⁶-methyladenosine (m⁶A) writer METTL3. We also showed that LINC00470-METTL3-mediated PTEN mRNA degradation relied on the m⁶A reader protein YTHDF2-dependent pathway. Taken together, LINC00470 might serve as a therapeutic target for GC patients.

Multidisciplinary Teams Improve Gastric Cancer Treatment Efficiency at a Large Safety Net Hospital

BACKGROUND

Gastric cancer treatment initiation is a complex process. Inefficiencies in care coordination can lead to significant delays, which are often more prominent at safety net hospitals. Multidisciplinary teams (MDTs) have been proposed as an effective solution.

METHODS

A retrospective review of sequential gastric cancer patients receiving treatment at Parkland Hospital (Dallas, TX) between 2013 and 2015 was performed before (n = 50) and after (n = 50) creation of a MDT and standardized care pathways. Patients undergoing urgent resection were excluded. Time to treatment (TTT) from initial endoscopy to initiation of chemotherapy was evaluated. The number of diagnostic tests performed and treatment variability also were compared.

RESULTS

Groups were similar in terms of age, sex, stage distribution, tumor location, and type of presentation (outpatient vs. emergency room). Post-intervention, TTT decreased from 84.1 ± 12.3 to 32.5 ± 15.2 days (p < 0.02). This decrease was primarily related to parallel performance of subspecialty evaluations, staging studies, and procedures. MDT review reduced the number of unnecessary staging tests performed, leading to a decrease in the average number of studies from 3.8 per patient to 2.2 (p < 0.05). Use of diagnostic laparoscopy in patients with clinically locally advanced disease increased from 18 to 94% (p < 0.05).

CONCLUSIONS

Creation of a gastric cancer MDT and uniform care pathways at a large safety net hospital expedited initiation of treatment, reduced unnecessary tests, and promoted consistent patient management.