Comprehensive molecular characterization of gastric adenocarcinoma

Gastric cancer is a leading cause of cancer deaths, but analysis of its molecular and clinical characteristics has been complicated by histological and aetiological heterogeneity. Here we describe a comprehensive molecular evaluation of 295 primary gastric adenocarcinomas as part of The Cancer Genome Atlas (TCGA) project. We propose a molecular classification dividing gastric cancer into four subtypes: tumours positive for Epstein-Barr virus, which display recurrent PIK3CA mutations, extreme DNA hypermethylation, and amplification of JAK2, CD274 (also known as PD-L1) and PDCD1LG2 (also known as PD-L2); microsatellite unstable tumours, which show elevated mutation rates, including mutations of genes encoding targetable oncogenic signalling proteins; genomically stable tumours, which are enriched for the diffuse histological variant and mutations of RHOA or fusions involving RHO-family GTPase-activating proteins; and tumours with chromosomal instability, which show marked aneuploidy and focal amplification of receptor tyrosine kinases. Identification of these subtypes provides a roadmap for patient stratification and trials of targeted therapies.

Gastric cancer: descriptive epidemiology, risk factors, screening, and prevention

Less than a century ago, gastric cancer was the most common cancer in the United States and perhaps throughout the world. Despite its worldwide decline in incidence over the past century, gastric cancer remains a major killer across the globe. This article reviews the epidemiology, screening, and prevention of gastric cancer. We first discuss the descriptive epidemiology of gastric cancer, including its incidence, survival, mortality, and trends over time. Next, we characterize the risk factors for gastric cancer, both environmental and genetic. Serologic markers and histological precursor lesions of gastric cancer and early detection of gastric cancer using these markers are reviewed. Finally, we discuss prevention strategies and provide suggestions for further research.

Epidemiology of gastric cancer

The incidence and mortality of gastric cancer have fallen dramatically in US and elsewhere over the past several decades. Nonetheless, gastric cancer remains a major public health issue as the fourth most common cancer and the second leading cause of cancer death worldwide. Demographic trends differ by tumor location and histology. While there has been a marked decline in distal, intestinal type gastric cancers, the incidence of proximal, diffuse type adenocarcinomas of the gastric cardia has been increasing, particularly in the Western countries. Incidence by tumor sub-site also varies widely based on geographic location, race, and socio-economic status. Distal gastric cancer predominates in developing countries, among blacks, and in lower socio-economic groups, whereas proximal tumors are more common in developed countries, among whites, and in higher socio-economic classes. Diverging trends in the incidence of gastric cancer by tumor location suggest that they may represent two diseases with different etiologies. The main risk factors for distal gastric cancer include Helicobacter pylori (H pylori) infection and dietary factors, whereas gastroesophageal reflux disease and obesity play important roles in the development of proximal stomach cancer. The purpose of this review is to examine the epidemiology and risk factors of gastric cancer, and to discuss strategies for primary prevention.

Patient survival after D1 and D2 resections for gastric cancer: long-term results of the MRC randomized surgical trial. Surgical Co-operative Group

Controversy still exists on the optimal surgical resection for potentially curable gastric cancer. Much better long-term survival has been reported in retrospective/non-randomized studies with D2 resections that involve a radical extended regional lymphadenectomy than with the standard D1 resections. In this paper we report the long-term survival of patients entered into a randomized study, with follow-up to death or 3 years in 96% of patients and a median follow-up of 6.5 years. In this prospective trial D1 resection (removal of regional perigastric nodes) was compared with D2 resection (extended lymphadenectomy to include level 1 and 2 regional nodes). Central randomization followed a staging laparotomy. Out of 737 patients with histologically proven gastric adenocarcinoma registered, 337 patients were ineligible by staging laparotomy because of advanced disease and 400 were randomized. The 5-year survival rates were 35% for D1 resection and 33% for D2 resection (difference -2%, 95% CI = -12%-8%). There was no difference in the overall 5-year survival between the two arms (HR = 1.10, 95% CI 0.87-1.39, where HR > 1 implies a survival benefit to D1 surgery). Survival based on death from gastric cancer as the event was similar in the D1 and D2 groups (HR = 1.05, 95% CI 0.79-1.39) as was recurrence-free survival (HR = 1.03, 95% CI 0.82-1.29). In a multivariate analysis, clinical stages II and III, old age, male sex and removal of spleen and pancreas were independently associated with poor survival. These findings indicate that the classical Japanese D2 resection offers no survival advantage over D1 surgery. However, the possibility that D2 resection without pancreatico-splenectomy may be better than standard D1 resection cannot be dismissed by the results of this trial.

Current treatment and recent progress in gastric cancer

Gastric cancer is not a top-10 malignancy in the United States but represents one of the most common causes of cancer death worldwide. Biological differences between tumors from Eastern and Western countries add to the complexity of identifying standard-of-care therapy based on international trials. Systemic chemotherapy, radiotherapy, surgery, immunotherapy, and targeted therapy all have proven efficacy in gastric adenocarcinoma; therefore, multidisciplinary treatment is paramount to treatment selection. Triplet chemotherapy for resectable gastric cancer is now accepted and could represent a plateau of standard cytotoxic chemotherapy for localized disease. Classification of gastric cancer based on molecular subtypes is providing an opportunity for personalized therapy. Biomarkers, in particular microsatellite instability (MSI), programmed cell death ligand 1 (PD-L1), human epidermal growth factor receptor 2 (HER2), tumor mutation burden, and Epstein-Barr virus, are increasingly driving systemic therapy approaches and allowing for the identification of populations most likely to benefit from immunotherapy and targeted therapy. Significant research opportunities remain for the less differentiated histologic subtypes of gastric adenocarcinoma and those without markers of immunotherapy activity.

Gastric Cancer: Epidemiology, Risk Factors, Classification, Genomic Characteristics and Treatment Strategies

Gastric cancer (GC) is one of the most common malignancies worldwide and it is the fourth leading cause of cancer-related death. GC is a multifactorial disease, where both environmental and genetic factors can have an impact on its occurrence and development. The incidence rate of GC rises progressively with age; the median age at diagnosis is 70 years. However, approximately 10% of gastric carcinomas are detected at the age of 45 or younger. Early-onset gastric cancer is a good model to study genetic alterations related to the carcinogenesis process, as young patients are less exposed to environmental carcinogens. Carcinogenesis is a multistage disease process specified by the progressive development of mutations and epigenetic alterations in the expression of various genes, which are responsible for the occurrence of the disease.

Cross-validation of survival associated biomarkers in gastric cancer using transcriptomic data of 1,065 patients

Introduction

Multiple gene expression based prognostic biomarkers have been repeatedly identified in gastric carcinoma. However, without confirmation in an independent validation study, their clinical utility is limited. Our goal was to establish a robust database enabling the swift validation of previous and future gastric cancer survival biomarker candidates.

Results

The entire database incorporates 1,065 gastric carcinoma samples, gene expression data. Out of 29 established markers, higher expression of BECN1 (HR = 0.68, p = 1.5E-05), CASP3 (HR = 0.5, p = 6E-14), COX2 (HR = 0.72, p = 0.0013), CTGF (HR = 0.72, p = 0.00051), CTNNB1 (HR = 0.47, p = 4.3E-15), MET (HR = 0.63, p = 1.3E-05), and SIRT1 (HR = 0.64, p = 2.2E-07) correlated to longer OS. Higher expression of BIRC5 (HR = 1.45, p = 1E-04), CNTN1 (HR = 1.44, p = 3.5E- 05), EGFR (HR = 1.86, p = 8.5E-11), ERCC1 (HR = 1.36, p = 0.0012), HER2 (HR = 1.41, p = 0.00011), MMP2 (HR = 1.78, p = 2.6E-09), PFKB4 (HR = 1.56, p = 3.2E-07), SPHK1 (HR = 1.61, p = 3.1E-06), SP1 (HR = 1.45, p = 1.6E-05), TIMP1 (HR = 1.92, p = 2.2E- 10) and VEGF (HR = 1.53, p = 5.7E-06) were predictive for poor OS.

MATERIALS AND METHODS

We integrated samples of three major cancer research centers (Berlin, Bethesda and Melbourne datasets) and publicly available datasets with available follow-up data to form a single integrated database. Subsequently, we performed a literature search for prognostic markers in gastric carcinomas (PubMed, 2012–2015) and re-validated their findings predicting first progression (FP) and overall survival (OS) using uni- and multivariate Cox proportional hazards regression analysis.

Conclusions

The major advantage of our analysis is that we evaluated all genes in the same set of patients thereby making direct comparison of the markers feasible. The best performing genes include BIRC5, CASP3, CTNNB1, TIMP-1, MMP-2, SIRT, and VEGF.

Gastric cancer: epidemiology, prevention, classification, and treatment

Gastric cancer is the second most common cause of cancer-related deaths in the world, the epidemiology of which has changed within last decades. A trend of steady decline in gastric cancer incidence rates is the effect of the increased standards of hygiene, conscious nutrition, and Helicobacter pylori eradication, which together constitute primary prevention. Avoidance of gastric cancer remains a priority. However, patients with higher risk should be screened for early detection and chemoprevention. Surgical resection enhanced by standardized lymphadenectomy remains the gold standard in gastric cancer therapy. This review briefly summarizes the most important aspects of gastric cancers, which include epidemiology, risk factors, classification, diagnosis, prevention, and treatment. The paper is mostly addressed to physicians who are interested in updating the state of art concerning gastric carcinoma from easily accessible and credible source.

Epidemiology of gastric cancer: global trends, risk factors and prevention

Gastric cancer remains one of the most common and deadly cancers worldwide, especially among older males. Based on GLOBOCAN 2018 data, stomach cancer is the 5^th most common neoplasm and the 3^rd most deadly cancer, with an estimated 783,000 deaths in 2018. Gastric cancer incidence and mortality are highly variable by region and highly dependent on diet and Helicobacter pylori infection. While strides in preventing and treating H. pylori infection have decreased the overall incidence of gastric cancer, they have also contributed to an increase in the incidence of cardia gastric cancer, a rare subtype of the neoplasm that has grown 7-fold in the past decades. A better understanding of the etiology and risk factors of the disease can help reach a consensus in approaching H. pylori infection. Dietary modification, smoking cessation, and exercise hold promise in preventing gastric cancer, while genetic testing is enabling earlier diagnosis and thus greater survival.

Global burden of gastric cancer attributable to Helicobacter pylori

We previously estimated that 660,000 cases of cancer in the year 2008 were attributable to the bacterium Helicobacter pylori (H. pylori), corresponding to 5.2% of the 12.7 million total cancer cases that occurred worldwide. In recent years, evidence has accumulated that immunoblot (western blot) is more sensitive for detection of anti-H. pylori antibodies than ELISA, the detection method used in our previous analysis. The purpose of this short report is to update the attributable fraction (AF) estimate for H. pylori after briefly reviewing new evidence, and to reassess the global burden of cancer attributable to H. pylori. We therefore reviewed the literature for studies comparing the risk of developing non-cardia gastric cancer (NCGC) in cases and controls, using both ELISA and multiple antigen immunoblot for detection of H. pylori. The results from prospective studies were combined, and the new pooled estimates were applied to the calculation of the AF for H. pylori in NCGC, then to the burden of infection-related cancers worldwide. Using the immunoblot-based data, the worldwide AF for H. pylori in NCGC increased from 74.7% to 89.0%. This implies approximately 120,000 additional cases of NCGC attributable to H. pylori infection for a total of around 780,000 cases (6.2% instead of 5.2% of all cancers). These updated estimates reinforce the role of H. pylori as a major cause of cancer.

METTL3-mediated m6A modification of HDGF mRNA promotes gastric cancer progression and has prognostic significance

OBJECTIVE

N⁶-methyladenosine (m⁶A) RNA methylation and its associated methyltransferase METTL3 are involved in tumour initiation and progression via the regulation of RNA function. This study explored the biological function and clinical significance of METTL3 in gastric cancer (GC).

DESIGN

The prognostic value of METTL3 expression was evaluated using tissue microarray and immunohistochemical staining analyses in a human GC cohort. The biological role and mechanism of METTL3 in GC tumour growth and liver metastasis were determined in vitro and in vivo.

RESULTS

The level of m⁶A RNA was significantly increased in GC, and METTL3 was the main regulator involved in the abundant m⁶A RNA modification. METTL3 expression was significantly elevated in GC tissues and associated with poor prognosis. Multivariate Cox regression analysis revealed that METTL3 expression was an independent prognostic factor and effective predictor in human patients with GC. Moreover, METTL3 overexpression promoted GC proliferation and liver metastasis in vitro and in vivo. Mechanistically, P300-mediated H3K27 acetylation activation in the promoter of METTL3 induced METTL3 transcription, which stimulated m⁶A modification of HDGF mRNA, and the m⁶A reader IGF2BP3 then directly recognised and bound to the m⁶A site on HDGF mRNA and enhanced HDGF mRNA stability. Secreted HDGF promoted tumour angiogenesis, while nuclear HDGF activated GLUT4 and ENO2 expression, followed by an increase in glycolysis in GC cells, which was correlated with subsequent tumour growth and liver metastasis.

CONCLUSIONS

Elevated METTL3 expression promotes tumour angiogenesis and glycolysis in GC, indicating that METTL3 expression is a potential prognostic biomarker and therapeutic target for human GC.

Management of Helicobacter pylori infection: the Maastricht VI/Florence consensus report

Helicobacter pyloriInfection is formally recognised as an infectious disease, an entity that is now included in the International Classification of Diseases 11th Revision. This in principle leads to the recommendation that all infected patients should receive treatment. In the context of the wide clinical spectrum associated with Helicobacter pylori gastritis, specific issues persist and require regular updates for optimised management.The identification of distinct clinical scenarios, proper testing and adoption of effective strategies for prevention of gastric cancer and other complications are addressed. H. pylori treatment is challenged by the continuously rising antibiotic resistance and demands for susceptibility testing with consideration of novel molecular technologies and careful selection of first line and rescue therapies. The role of H. pylori and antibiotic therapies and their impact on the gut microbiota are also considered.Progress made in the management of H. pylori infection is covered in the present sixth edition of the Maastricht/Florence 2021 Consensus Report, key aspects related to the clinical role of H. pylori infection were re-evaluated and updated. Forty-one experts from 29 countries representing a global community, examined the new data related to H. pylori infection in five working groups: (1) indications/associations, (2) diagnosis, (3) treatment, (4) prevention/gastric cancer and (5) H. pylori and the gut microbiota. The results of the individual working groups were presented for a final consensus voting that included all participants. Recommendations are provided on the basis of the best available evidence and relevance to the management of H. pylori infection in various clinical fields.

A comprehensive survey of genomic alterations in gastric cancer reveals systematic patterns of molecular exclusivity and co-occurrence among distinct therapeutic targets

OBJECTIVE

Gastric cancer is a major gastrointestinal malignancy for which targeted therapies are emerging as treatment options. This study sought to identify the most prevalent molecular targets in gastric cancer and to elucidate systematic patterns of exclusivity and co-occurrence among these targets, through comprehensive genomic analysis of a large panel of gastric cancers.

DESIGN

Using high-resolution single nucleotide polymorphism arrays, copy number alterations were profiled in a panel of 233 gastric cancers (193 primary tumours, 40 cell lines) and 98 primary matched gastric non-malignant samples. For selected alterations, their impact on gene expression and clinical outcome were evaluated.

RESULTS

22 recurrent focal alterations (13 amplifications and nine deletions) were identified. These included both known targets (FGFR2, ERBB2) and also novel genes in gastric cancer (KLF5, GATA6). Receptor tyrosine kinase (RTK)/RAS alterations were found to be frequent in gastric cancer. This study also demonstrates, for the first time, that these alterations occur in a mutually exclusive fashion, with KRAS gene amplifications highlighting a clinically relevant but previously underappreciated gastric cancer subgroup. FGFR2-amplified gastric cancers were also shown to be sensitive to dovitinib, an orally bioavailable FGFR/VEGFR targeting agent, potentially representing a subtype-specific therapy for FGFR2-amplified gastric cancers.

CONCLUSION

The study demonstrates the existence of five distinct gastric cancer patient subgroups, defined by the signature genomic alterations FGFR2 (9% of tumours), KRAS (9%), EGFR (8%), ERBB2 (7%) and MET (4%). Collectively, these subgroups suggest that at least 37% of gastric cancer patients may be potentially treatable by RTK/RAS directed therapies.

A Comprehensive Human Gastric Cancer Organoid Biobank Captures Tumor Subtype Heterogeneity and Enables Therapeutic Screening

Gastric cancer displays marked molecular heterogeneity with aggressive behavior and treatment resistance. Therefore, good in vitro models that encompass unique subtypes are urgently needed for precision medicine development. Here, we have established a primary gastric cancer organoid (GCO) biobank that comprises normal, dysplastic, cancer, and lymph node metastases (n = 63) from 34 patients, including detailed whole-exome and transcriptome analysis. The cohort encompasses most known molecular subtypes (including EBV, MSI, intestinal/CIN, and diffuse/GS, with CLDN18-ARHGAP6 or CTNND1-ARHGAP26 fusions or RHOA mutations), capturing regional heterogeneity and subclonal architecture, while their morphology, transcriptome, and genomic profiles remain closely similar to in vivo tumors, even after long-term culture. Large-scale drug screening revealed sensitivity to unexpected drugs that were recently approved or in clinical trials, including Napabucasin, Abemaciclib, and the ATR inhibitor VE-822. Overall, this new GCO biobank, with linked genomic data, provides a useful resource for studying both cancer cell biology and precision cancer therapy.

MicroRNA-200c modulates epithelial-to-mesenchymal transition (EMT) in human colorectal cancer metastasis

OBJECTIVE

Distant metastasis is the major cause of cancer-related death in patients with colorectal cancer (CRC). Although the microRNA-200 (miR-200) family is a crucial inhibitor of epithelial-to-mesenchymal transition (EMT) in human cancer, the role of miR-200 members in the pathogenesis of metastatic CRC has not been investigated.

DESIGN

Fifty-four pairs of primary CRC and corresponding matched liver metastasis tissue specimens were analysed for expression and methylation status of the miR-200 family members. Functional analysis of miR-200c overexpression was investigated in CRC cell lines, and cells were analysed for proliferation, invasion and migration. Expression of several miR-200c target genes (ZEB1, ETS1 and FLT1) and EMT markers (E-cadherin and vimentin) in CRC cell lines and tissue specimens was validated.

RESULTS

Liver metastasis tissues showed higher expression of miR-200c (primary CRC = 1.31 vs. liver metastasis = 1.59; p = 0.0014) and miR-141 (primary CRC = 0.14 vs. liver metastasis = 0.17; p = 0.0234) than did primary CRCs, which was significantly associated with hypomethylation of the promoter region of these miRNAs (primary CRC = 61.2% vs. liver metastasis = 46.7%; p < 0.0001). The invasive front in primary CRC tissues revealed low miR-200c expression by in situ hybridization analysis. Transfection of miR-200c precursors resulted in enhanced cell proliferation but reduced invasion and migration behaviours in CRC cell lines. Overexpression of miR-200c in CRC cell lines caused reduced expression of putative gene targets, and resulted in increased E-cadherin and reduced vimentin expression. The associations between miR-200c, target genes and EMT markers were validated in primary CRCs and matching liver metastasis tissues.

CONCLUSIONS

miR-200c plays an important role in mediating EMT and metastatic behaviour in the colon. Its expression is epigenetically regulated, and miR-200c may serve as a potential diagnostic marker and therapeutic target for patients with CRC.

The Chinese Society of Clinical Oncology (CSCO): Clinical guidelines for the diagnosis and treatment of gastric cancer, 2021

There exist differences in the epidemiological characteristics, clinicopathological features, tumor biological characteristics, treatment patterns, and drug selections between gastric cancer patients from the Eastern and Western countries. The Chinese Society of Clinical Oncology (CSCO) has organized a panel of senior experts specializing in all sub-specialties of gastric cancer to compile a clinical guideline for the diagnosis and treatment of gastric cancer since 2016 and renews it annually. Taking into account regional differences, giving full consideration to the accessibility of diagnosis and treatment resources, these experts have conducted expert consensus judgment on relevant evidence and made various grades of recommendations for the clinical diagnosis and treatment of gastric cancer to reflect the value of cancer treatment and meeting health economic indexes in China. The 2021 CSCO Clinical Practice Guidelines for Gastric Cancer covers the diagnosis, treatment, follow-up, and screening of gastric cancer. Based on the 2020 version of the CSCO Chinese Gastric Cancer guidelines, this updated guideline integrates the results of major clinical studies from China and overseas for the past year, focused on the inclusion of research data from the Chinese population for more personalized and clinically relevant recommendations. For the comprehensive treatment of non-metastatic gastric cancer, attentions were paid to neoadjuvant treatment. The value of perioperative chemotherapy is gradually becoming clearer and its recommendation level has been updated. For the comprehensive treatment of metastatic gastric cancer, recommendations for immunotherapy were included, and immune checkpoint inhibitors from third-line to the first-line of treatment for different patient groups with detailed notes are provided.

Gastric cancer: overview

This review provides a state of the art description of gastric cancer etiology, the infectious agent, host factors, the precancerous cascade, clinical aspects, and prevention strategies. The biology of Helicobacter pylori, the primary causative agent, is discussed as well as the environmental factors that may modulate its effects.

HER2 screening data from ToGA: targeting HER2 in gastric and gastroesophageal junction cancer

BACKGROUND

In the Trastuzumab for GAstric cancer (ToGA) study, trastuzumab plus chemotherapy improved median overall survival by 2.7 months in patients with human epidermal growth factor receptor 2 (HER2)-positive [immunohistochemistry (IHC) 3+/fluorescence in situ hybridization-positive] gastric/gastroesophageal junction cancer compared with chemotherapy alone (hazard ratio 0.74). Post hoc exploratory analyses in patients expressing higher HER2 levels (IHC 2+/fluorescence in situ hybridization-positive or IHC 3+) demonstrated a 4.2-month improvement in median overall survival with trastuzumab (hazard ratio 0.65). The ToGA study provides the largest screening dataset available on HER2 overexpression/amplification in this indication. We further analyzed correlation(s) of HER2 overexpression/amplification with clinical and epidemiological factors.

METHODS

HER2-positivity was analyzed by histological subtype, tumor location, geographic region, and specimen type. Exploratory efficacy analyses were performed.

RESULTS

The HER2-positivity rate was 22.1 % across analyzed tumor samples. Rates were similar between European and Asian patients (23.6 % vs. 23.9 %), but higher in intestinal- vs. diffuse-type (31.8 % vs. 6.1 %), and gastroesophageal junction cancer versus gastric tumors (32.2 % vs. 21.4 %). Across all IHC scores, variability in HER2 staining (≤30 % stained cells) was observed in almost 50 % of cases, with increasing rates in lower IHC categories, and did not affect treatment outcome. The polysomy rate was 4 %.

CONCLUSIONS

HER2 expression varies by tumor location and type. All patients with advanced gastric or gastroesophageal junction cancer should be tested for HER2 status, preferably using IHC initially. Due to the unique characteristics of gastric cancer, specific testing/scoring guidelines should be adhered to.

Nitric oxide and cancer: a review

Nitric oxide (NO), is a ubiquitous, water soluble, free radical gas, which plays key role in various physiological as well as pathological processes. Over past decades, NO has emerged as a molecule of interest in carcinogenesis and tumor growth progression. However, there is considerable controversy and confusion in understanding its role in cancer biology. It is said to have both tumoricidal as well as tumor promoting effects which depend on its timing, location, and concentration. NO has been suggested to modulate different cancer-related events including angiogenesis, apoptosis, cell cycle, invasion, and metastasis. On the other hand, it is also emerging as a potential anti-oncogenic agent. Strategies for manipulating in vivo production and exogenous delivery of this molecule for therapeutic gain are being investigated. However, further validation and experimental/clinical trials are required for development of novel strategies based on NO for cancer treatment and prevention. This review discusses the range of actions of NO in cancer by performing an online MEDLINE search using relevant search terms and a review of the literature. Various mechanisms by which NO acts in different cancers such as breast, cervical, gastric,colorectal, and head and neck cancers are addressed. It also offers an insight into the dichotomous nature of NO and discusses its novel therapeutic applications for cancer prevention and treatment.

Peritoneal carcinomatosis of gastric origin: a population-based study on incidence, survival and risk factors

Peritoneal carcinomatosis (PC) is an important cause of morbidity and mortality among patients with gastric cancer. The aim of the current study was to provide reliable population-based data on the incidence, risk factors and prognosis of PC of gastric origin. All patients diagnosed with gastric cancer in the area of the Eindhoven Cancer Registry between 1995 and 2011 were included. Incidence and survival were computed and risk factors for peritoneal carcinomatosis were determined using multivariate logistic regression analysis. In total, 5,220 patients were diagnosed with gastric cancer, of whom 2,029 (39%) presented with metastatic disease. PC was present in 706 patients (14%) of whom 491 patients (9%) had PC as the only metastatic site. Younger age (<60 years), female gender, advanced T- and N-stage, primary tumor of signet ring cells or linitis plastica and primary tumors covering multiple anatomical locations of the stomach were all associated with a higher odds ratios of developing PC. Median survival of patients without metastases was 14 months, but only 4 months for patients with PC. PC is a frequent condition in patients presenting with gastric cancer, especially in younger patients with advanced tumor stages. Given the detrimental influence of PC on survival, efforts should be undertaken to further explore the promising results that were obtained in preventing or treating this condition with multimodality strategies.

Meta-analysis shows that prevalence of Epstein-Barr virus-positive gastric cancer differs based on sex and anatomic location

BACKGROUND & AIMS

Epstein-Barr virus (EBV) has been causally associated with cancer; some gastric carcinomas have a monoclonal EBV genome in every cancer cell, indicating that they arose from a single infected progenitor cell. However, the proportion of EBV-positive gastric carcinomas is uncertain, and the etiologic significance is unknown.

METHODS

We conducted a meta-analysis of 70 studies including 15,952 cases of gastric cancer assessed by in situ hybridization for EBV-encoded small RNA.

RESULTS

The pooled prevalence estimate of EBV positivity was 8.7% (95% confidence interval [CI]: 7.5%-10.0%) overall, with a 2-fold difference by sex: 11.1% (95% CI: 8.7%-14.1%) of gastric cancer cases in males vs 5.2% (95% CI: 3.6%-7.4%) of cases in females. Tumors arising in the gastric cardia (13.6%) or corpus (13.1%) were more than twice as likely to be EBV-positive as those in the antrum (5.2%; P < .01 for both comparisons). EBV prevalence was 4 times higher (35.1%) for tumors in postsurgical gastric stump/remnants. Over 90% of lymphoepithelioma-like carcinomas were EBV positive, but only 15 studies reported any cases of this type; prevalence did not significantly differ between the more common diffuse (9.5%) [corrected] and intestinal (7.6%) [corrected] histologies. EBV prevalence was similar in cases from Asia (8.3%), Europe (9.2%), and the Americas (9.9%).

CONCLUSIONS

EBV-positive gastric cancers greatly differ from other gastric carcinomas based on sex, anatomic subsite, and surgically disrupted anatomy, indicating that it is a distinct etiologic entity. Epidemiologic studies comparing EBV-positive and -negative gastric cancers are warranted to investigate EBV's role in gastric carcinogenesis.

Gastric cancer treated in 2002 in Japan: 2009 annual report of the JGCA nationwide registry

BACKGROUND

The Japanese Gastric Cancer Association (JGCA) started a new nationwide gastric cancer registration in 2008.

METHODS

From 208 participating hospitals, 53 items including surgical procedures, pathological diagnosis, and survival outcomes of 13,626 patients with primary gastric cancer treated in 2002 were collected retrospectively. Data were entered into the JGCA database according to the JGCA classification (13th edition) and UICC TNM classification (5th edition) using an electronic data collecting system. Finally, data of 13,002 patients who underwent laparotomy were analyzed.

RESULTS

The 5-year follow-up rate was 83.3 %. The direct death rate was 0.48 %. UICC 5-year survival rates (5YEARSs)/JGCA 5YEARSs were 92.2 %/92.3 % for stage IA, 85.3 %/84.7 % for stage IB, 72.1 %/70.0 % for stage II, 52.8 %/46.8 % for stage IIIA, 31.0 %/28.8 % for stage IIIB, and 14.9 %/15.3 % for stage IV, respectively. The proportion of patients more than 80 years old was 7.8 %, and their 5YEARS was 51.6 %. Postoperative outcome of the patients with primary gastric carcinoma in Japan have apparently improved in advanced cases and among the aged population when compared with the archival data. Further efforts to improve the follow-up rate are needed.

CONCLUSIONS

Postoperative outcome of the patients with primary gastric carcinoma in Japan have apparently improved in advanced cases and among the aged population when compared with the archival data. Further efforts to improve the follow-up rate are needed.

Nerve Growth Factor Promotes Gastric Tumorigenesis through Aberrant Cholinergic Signaling

Within the gastrointestinal stem cell niche, nerves help to regulate both normal and neoplastic stem cell dynamics. Here, we reveal the mechanisms underlying the cancer-nerve partnership. We find that Dclk1⁺ tuft cells and nerves are the main sources of acetylcholine (ACh) within the gastric mucosa. Cholinergic stimulation of the gastric epithelium induced nerve growth factor (NGF) expression, and in turn NGF overexpression within gastric epithelium expanded enteric nerves and promoted carcinogenesis. Ablation of Dclk1⁺ cells or blockade of NGF/Trk signaling inhibited epithelial proliferation and tumorigenesis in an ACh muscarinic receptor-3 (M3R)-dependent manner, in part through suppression of yes-associated protein (YAP) function. This feedforward ACh-NGF axis activates the gastric cancer niche and offers a compelling target for tumor treatment and prevention.

Safety, efficacy and tumor mutational burden as a biomarker of overall survival benefit in chemo-refractory gastric cancer treated with toripalimab, a PD-1 antibody in phase Ib/II clinical trial NCT02915432

BACKGROUND

High tumor mutational burden (TMB-H) is correlated with enhanced objective response rate (ORR) and progression-free survival (PFS) for certain cancers receiving immunotherapy. This study aimed to investigate the safety and efficacy of toripalimab, a humanized programmed death-1 (PD-1) antibody, in advanced gastric cancer (AGC), and the predictive survival benefit of TMB and PD-L1.

PATIENTS AND METHODS

We reported on the AGC cohort of phase Ib/II trial evaluating the safety and activity of toripalimab in patients with AGC, oesophageal squamous cell carcinoma, nasopharyngeal carcinoma and head and neck squamous cell carcinoma. In cohort 1, 58 chemo-refractory AGC patients received toripalimab (3 mg/kg d1, Q2W) as a monotherapy. In cohort 2, 18 chemotherapy-naive AGC patients received toripalimab (360 mg d1, Q3W) with oxaliplatin 130 mg/m2 qd, d1, capecitabine 1000 mg/m2 b.i.d., d1-d14, Q3W as first-line treatment. Primary end point was ORR. Biomarkers such as PD-L1 and TMB were evaluated for correlation with clinical efficacy.

RESULTS

In cohort 1, the ORR was 12.1% and the disease control rate (DCR) was 39.7%. Median PFS was 1.9 months and median OS was 4.8 months. The TMB-H group showed significant superior OS than the TMB-L group [14.6 versus 4.0 months, HR = 0.48 (96% CI 0.24-0.96), P = 0.038], while PD-L1 overexpression did not correlate with significant survival benefit. A 77.6% of patients experienced at least one treatment-related adverse event (TRAE), and 22.4% of patients experienced a grade 3 or higher TRAE. In cohort 2, the ORR was 66.7% and the DCR was 88.9%. A 94.4% of patients experienced at least one TRAE and 38.9% of patients experienced grade 3 or higher TRAEs.

CONCLUSIONS

Toripalimab has demonstrated a manageable safety profile and promising antitumor activity in AGC patients, especially in combination with XELOX. High TMB may be a predictive marker for OS of AGC patients receiving toripalimab as a single agent.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02915432.