Gastric cancer epidemiology and risk factors

The association between physical activity and risk of gastric cancer; an umbrella review

INTRODUCTION

Gastric cancer (GC), as a highly lethal malignancy, is the fourth most common malignancy and the second leading cause of cancer-related death worldwide. This study is an umbrella review of systematic reviews and meta-analyses to present an overview of the extent and reliability of the claimed association between physical activity and the likelihood of developing or dying from GC.

METHOD

This study was conducted following the Joanna Brigs Institute (JBI)'s methods for conducting umbrella reviews. A systematic search was performed in PubMed, Scopus, Web of Science, and ProQuest databases until July, 2024 with predefined keywords. Two independent authors assessed the Risk of Bias in included studies using the JBI critical appraisal tool for the assessment of the quality of systematic reviews and disagreements between the authors were resolved through discussion or the opinion of another author.

RESULT

Five systematic reviews were included in this analysis, offering a more comprehensive understanding of the inverse relationship between physical activity and gastric cancer risk. Compared to previous studies, this review provides stronger evidence that moderate-to-high levels of physical activity significantly reduce the overall risk of developing gastric cancer.

CONCLUSION

While a link between physical activity and reduced cancer risk is promising, further research is crucial to unravel the specific mechanisms at play and to quantify the impact of increased activity levels on cancer prevention. Based on the findings of this study, physical activity is found to be associated with a decreased risk of GC; however, the limitation of the evidence suggested a need for future studies on this topic.

Platycodin D induces apoptosis via regulating MAPK pathway and promotes autophagy in colon cancer cell

Platycodin D (PD) is the main component of triterpene saponins found in Platycodi radix. In this study, we observed a decrease in cell viability, an increase in apoptotic bodies, and an increase in the rate of apoptosis. Also, we observed an increase in cleaved PARP and Bax, a decrease in Bcl-2, and p-ERK, and an increase in p-p38 and p-JNK. Furthermore, a change in cell viability and the expression of p-p38, Bax, and Bcl-2 using the p38 inhibitor revealed a decrease in p-p38 and Bax and an increase in Bcl-2 in the inhibitor treatment group. In addition, we observed an increase in vacuole formation through morphological changes and an increase in acidic vesicular organelles (AVOs). We also observed an increase in the expression of beclin 1, LC 3-I, and -II. There was no significant decrease in cell viability in the group treated with 3-MA, but a decrease in cell viability was noted in the group treated with HCQ. HCQ treatment resulted in an increase in Bax and a decrease in Bcl-2. These findings reveal that in HT-29 colon cancer cells, PD induces apoptosis through the MAPK pathway, thereby exerting anticancer effects. Moreover, autophagy caused by PD inhibits apoptosis by protecting the cells.

Pathologic Features of Esophageal and Gastric Malignancies

Esophageal cancer is the eighth most common cancer globally, affecting approximately 570,000 people worldwide and currently ranking sixth among cancer-related mortality (Uhlenhopp et al. in, Clin J Gastroenterol 13:1010-1021, 2020). The prognosis is poor as many patients present with locally incurable or metastatic disease. In spite of advancements in treatment, the overall 5-year survival rates are in the realm of 10% whereas the 5-year post-esophagectomy survival rates are in the realm of 15-40% [2]. The incidence rates vary dramatically worldwide, which can be attributed to demographic and socioeconomic factors. Although the vast majority of esophageal neoplasms arise from the epithelial layer and include squamous cell carcinoma (SCC) and adenocarcinoma (AC), a subset of neuroendocrine and soft tissue tumors can also occur in the esophagus. Several tasks are presented to the surgical pathologist when dealing with esophageal carcinoma that include rendering a diagnosis, classifying the histological type, and assessing prognostic factors. This narrative review aims to evaluate current literature on various esophageal neoplasms and highlight pathological factors that impact clinical decision making and prognosis.

Carcinoma stomach in Eastern India-An audit from a tertiary health care center

BACKGROUND

In spite of declining incidence and fatality over the past decade, stomach cancer still remains a global health issue due to its aggressiveness and heterogeneity. There is wide variation in the epidemiology of stomach cancer, not only worldwide but also among different regions of India. However, there is very limited data available for the Indian population.

AIMS AND OBJECTIVE

This study was aimed at establishing the incidence and role of risk factors, analyzing the symptoms, stage of disease, and mode of various surgical treatments of patients in the eastern region of India, and comparing them with the results of other studies in India and regions outside India.

METHODS AND MATERIAL

An audit of the database of carcinoma stomach patients attending the radiotherapy and surgery outpatient department (OPD) between January 2020 and June 2021 was performed. Demographic, clinical, and treatment-related data were collected and analyzed with respect to other regions of India and the worldwide pattern of carcinoma stomach.

RESULTS

The mean age of the study population was 58 years with male dominance (70%). The antrum was the most common (60%) primary site, and stage III was the most common (47.6%) stage at presentation. Around 73.4% of patients underwent radical surgery. Most patients (50%) had an eventless post-operative period, and 76% received peri-operative chemotherapy. Also, 20% of patients received adjuvant chemoradiation.

CONCLUSION

Our analysis suggests that there are certain differences (like dietary habits), as well as similarities (like socio-demographic factors), among the risk factors of carcinoma in this part of the country than other parts. Further studies into the risk factors and different clinical presentations are required for prevention and early detection.

Current Progress on Predictive Biomarkers for Response to Immune Checkpoint Inhibitors in Gastric Cancer: How to Maximize the Immunotherapeutic Benefit?

Gastric cancer is the fifth most prevalent cancer and the fourth leading cause of cancer death globally. Delayed diagnosis and pronounced histological and molecular variations increase the complexity and challenge of treatment. Pharmacotherapy, which for a long time was systemic chemotherapy based on 5-fluorouracil, is the mainstay of management for advanced gastric cancer. Trastuzumab and programmed cell death 1 (PD-1) inhibitors have altered the therapeutic landscape, contributing to noticeably prolonged survivorship in patients with metastatic gastric cancer. However, research has revealed that immunotherapy is only beneficial to some individuals. Biomarkers, such as programmed cell death ligand 1 (PD-L1), microsatellite instability (MSI), and tumor mutational load (TMB), have been shown to correlate with immune efficacy in numerous studies and are increasingly employed for the selection of patients most likely to respond to immunotherapy. Gut microorganisms, genetic mutations like POLE/POLD1 and NOTCH4, tumor lymphoid infiltrating cells (TILs), and other novel biomarkers have the potential to develop into new predictors. Prospective immunotherapy for gastric cancer should be guided by a biomarker-driven precision management paradigm, and multidimensional or dynamic marker testing could be the way to go.

Prevalence and factors associated with atrophic gastritis and intestinal metaplasia: A multivariate, hospital-based, statistical analysis

BACKGROUND

Atrophic gastritis (AG) and intestinal metaplasia (IM) play an essential role in gastric carcinogenesis. This study aimed to determine the prevalence of AG and IM and their associated factors.

METHODS

Subjects who underwent upper endoscopy at Chiang Mai University Hospital from January 2018 to Dec 2021 were included. All participants were interviewed using a structured questionnaire to collect their personal histories. In addition, clinical and histological data and associated factors of AG and IM were analyzed.

RESULTS

A total of 947 subjects (mean age, 53.61 ± 9.73 years; 60% male) were included. The prevalence of AG and IM, diagnosed by histopathology, was 39% and 19%. Prevalence of AG and IM increased from 28% and 9% in those under 50 years to 43% and 30% in those above 60 (p < 0.05). In a multivariate analysis, Helicobacter pylori (H. pylori) infection, age 50-59 and over 60 years were significantly associated with higher odds of AG (odds ratio (OR), 2.07, 2.06, and 1.98) and IM (OR, 2.07, 2.18, and 4.46), respectively. Conversely, ingestion of spicy food was significantly associated with lower odds of AG and IM (OR, 0.75, and 0.62).

CONCLUSIONS

This study confirms that age and H. pylori infection are risk factors, whereas spicy food intake is a protective factor against AG and IM, which are common in patients over 50. Therefore, upper endoscopy and gastric mapping sampling are recommended for patients with chronic dyspepsia older than 50 to reduce gastric cancer risk.

Risk prediction model of peritoneal seeding in advanced gastric cancer: A decision tool for diagnostic laparoscopy

BACKGROUND

Selective diagnostic laparoscopy in gastric cancer patients at high risk of peritoneal metastasis is essential for optimal treatment planning. In this study available clinicopathologic factors predictive of peritoneal seeding in advanced gastric cancer (AGC) were identified, and this information was translated into a clinically useful tool.

METHODS

Totally 2833 patients underwent surgery for AGC between 2003 and 2013. The study identified clinicopathologic factors associated with the risk of peritoneal seeding for constructing nomograms using a multivariate logistic regression model with backward elimination. A nomogram was constructed to generate a numerical value indicating risk. Accuracy was validated using bootstrapping and cross-validation.

RESULTS

The proportion of seeding positive was 12.7% in females and 9.6% in males. Of 2833 patients who underwent surgery for AGC, 300 (10.6%) were intraoperatively identified with peritoneal seeding. Multivariate analysis revealed the following factors associated with peritoneal seeding: high American Society of Anesthesiologists score, fibrinogen, Borrmann type 3 or 4 tumors, the involvement of the middle, anterior, and greater curvature, cT3 or cT4cN1 or cN2 or cN3, cM1, and the presence of ascites or peritoneal thickening or plaque or a nodule on the peritoneal wall on computed tomography. The bootstrap analysis revealed a robust concordance between mean and final parameter estimates. The area under the ROC curve for the final model was 0.856 (95% CI, 0.835-0.877), which implies good performance.

CONCLUSIONS

This nomogram provides effective risk estimates of peritoneal seeding from gastric cancer and can facilitate individualized decision-making regarding the selective use of diagnostic laparoscopy.

Safety and Efficacy of a First-Line Chemotherapy Tailored by G8 Score in Elderly Metastatic or Locally Advanced Gastric and Gastro-Esophageal Cancer Patients: A Real-World Analysis

Introduction: Gastric (GC) and gastro-esophageal cancer (GEC) are common neoplasms in the elderly. However, in clinical practice, the correct strategy for elderly patients who might benefit from chemotherapy (CT) is unknown. Prospective data are still poor. In this context, we performed a retrospective analysis of GC patients aged ≥75 years and treated at our institutions. Material and Methods: We retrospectively analyzed 90 patients with confirmed metastatic GC or GEC, treated with an upfront CT. Inclusion criteria were patients aged ≥75 years, PS 0−2, normal bone marrow/liver/renal function and no major comorbidities. All patients received a G8 score, and some patients with G8 ≤14 received a comprehensive geriatric assessment (CGA). The primary goal was to perform a safety evaluation based on the incidence of adverse events (AE), and the secondary goal was to determine the efficacy (PFS and OS). The chi-square test and the Kaplan−Meier method were used to estimate the outcomes. The statistical significance level was set at p < 0.05. Results: Toxicity rates were quite low: G1/G2 (51.1%) and G3/G4 (25.5%). No toxic deaths were reported. The median PFS was 6.21 months and the median OS 11 months. The G8 score and PS ECOG significantly influenced both PFS and OS. A statistically significant correlation among G8, weight loss, hypoalbuminemia and risk of G3/G4 adverse events was also found. Conclusion: Our research on selected elderly patients did not detect broad differences of efficacy and tolerability compared to a young population. Our study, although retrospective and small-sized, showed that G8 score might be an accurate tool to identify elderly GC/GEC patients who could be safely treated with CT, further recognizing patients who could receive a doublet CT and who may require a single agent chemotherapy or a baseline dose reduction.

Virulence Genes of Helicobacter pylori Increase the Risk of Premalignant Gastric Lesions in a Colombian Population

BACKGROUND

Genetic variability of Helicobacter pylori is associated with various gastrointestinal diseases; however, little is known about interaction with sociodemographic in the development of premalignant lesions in Colombian patients.

METHODS

An analytical study was conducted including cases (patients with gastric atrophy, intestinal metaplasia, and gastric dysplasia) and controls (patients with nonatrophic gastritis). Sociodemographic information was obtained using a questionnaire. Histopathological diagnosis was performed according to the Sydney System. The cagA and vacA genotypes were established using polymerase chain reaction in paraffin blocks. The effect of each variable on the study outcome (premalignant lesion) is presented as odds ratio (OR) and 95% CI. A p value of <0.05 was considered as statistically significant.

RESULTS

The vacA/s1m1 genotype increases the risk of developing premalignant lesions of the stomach (OR: 3.05, 95% IC: 1.57-5.91, p=0.001). Age and educational level showed a positive interaction with the s1m1 genotype (adjusted OR: 3.68, 95% CI: 1.73-7.82, p=0.001). The cagA genotype was not correlated to the development of premalignant lesions of the stomach (OR: 1.32, 95% CI: 0.90-1.94, p=0.151).

CONCLUSIONS

The vacA genotype, age, and educational level are indicators of the risk of developing premalignant lesions of the stomach in the study population. Significance Statement. Genetic variability of H. pylori and sociodemographic information could be used to predict the risk of premalignant lesions in stomach in Colombian population.

Early gastric neoplasms are significant risk factor for colorectal adenoma: A prospective case-control study

Although gastric cancer patients have a high incidence and risk of colorectal cancer, evidence is lacking regarding whether early gastric neoplasms (EGNs), such as gastric adenomas and early gastric cancer, are risk factors for colorectal adenoma. This study aimed to investigate the incidence of colorectal adenomas in patients with EGN. This prospective study was conducted between January 2015 and December 2016. Of the 307 patients who underwent gastric endoscopic submucosal dissection for EGN, 110 patients were enrolled in the EGN group, and 110 age- and sex-matched healthy persons from the screening population were included in the control group in a 1:1 ratio. Demographic factors and results of colonoscopy, including quality assessment, were collected, and analyzed. No significant differences in the quality of colonoscopy, including bowel preparation, cecal intubation rate, and withdrawal time between the 2 groups, were observed. The incidence of colorectal adenoma was significantly higher in the EGN group than in the control group (55.5% vs 26.4%, P = .001). Multivariate analysis confirmed that old age (odds ratio: 1.04, 95% confidence interval: 1.01-1.08, P = .005) and a history of EGN (odds ratio: 4.99, 95% confidence interval: 2.60-9.57, P = .001) were independent risk factors for colorectal adenoma. This is the first prospective study to reflect the quality indicator of colonoscopy and confirmed that old age and a history of EGN are significant risk factors for colorectal adenomas. Therefore, more stringent colonoscopy surveillance should be considered in elderly patients with EGN.

Functional mechanism and clinical implications of miR-141 in human cancers

Cancer is caused by the abnormal proliferation of local tissue cells under the control of many oncogenic factors. MicroRNAs (miRNAs) are a class of evolutionarily conserved, approximately 22-nucleotide noncoding small RNAs that influence transcriptional regulationby binding to the 3'-untranslated region of target messenger RNA. As a member of the miRNA family, miR-141 acts as a suppressor or an oncomiR in various cancers and regulates cancer cell proliferation, apoptosis, invasion, and metastasis through a variety of signaling pathways, such as phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) and constitutive activation of nuclear factor-κB (NF-κB). Target gene validation and pathway analysis have provided mechanistic insight into the role of this miRNA in different tissues. This review also outlines novel findings that suggest miR-141 may be useful as a noninvasive biomarker and as a therapeutic target in several cancers.

LINC00922 promotes deterioration of gastric cancer

Several studies have demonstrated the association of lncRNAs with a variety of cancers. Here, we explored the role of LINC00922 in gastric cancer (GC) using bioinformatics approaches and in vitro experiments. We examined the expression of LINC00922 and the prognosis of GC patients based on data from The Cancer Genome Atlas (TCGA) and Gene Expression Profiling Interactive Analysis (GEPIA). LINC00922-related genes were identified by the Multi Experiment Matrix (MEM) database and The Atlas of Noncoding RNAs in Cancer (TANRIC), followed by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein-protein interaction analysis. The significance of LINC00922 in cell proliferation, apoptosis, invasion and migration was assessed by MTT assay, flow cytometry, Transwell assay and wound-healing assay. The expression of LINC00922 was increased in GC tissues compared with adjacent non-tumor tissues, and increased LINC00922 expression was correlated with poor overall survival and disease-free survival. In addition, 336 overlapping genes were identified by the MEM database and TANRIC and found to be involved in GC-related biological processes, such as cell adhesion and migration, as well as TGF-β signaling. In the protein-protein interaction network, hub genes, such as FSTL3 and LAMC1, were identified. LINC00922 overexpression significantly promoted cell proliferation and invasion in vitro, whereas LINC00922 knockdown exerted opposite effects. In summary, our findings indicate that LINC00922 is overexpressed in GC tissues, suggesting that it might play a role in the development and progression of GC, and thus, it might serve as a prognostic indicator of GC.

Sex-based differences in histology, staging, and prognosis among 2983 gastric cancer surgery patients

BACKGROUND

Few studies have been conducted on sex differences in the incidence, pathophysiology, and prognosis of gastric cancer (GC).

AIM

To analyze the differences in GC characteristics according to sex in patients who underwent surgical treatment for GC.

METHODS

A total of 2983 patients diagnosed with gastric adenocarcinoma who received surgical treatment at the Seoul National University Bundang Hospital between 2003 and 2017 were included. Baseline clinicopathological characteristics, histologic type of GC, overall and GC-specific survival rates, and associated risk factors were analyzed.

RESULTS

Among the 2983 patients, 2005 (67.2%) and 978 (32.8%) were males and females, respectively. The average age of the female group (59.36 years) was significantly younger than that of the male group (61.66 years; P < 0.001). Cancer of the gastric body (P < 0.001) and diffuse-type histology (P < 0.001) were more common in females than in males. This trend was more prominent in females younger than 60 years of age, with a significantly higher proportion of diffuse-type cancer than in the male group. Regardless of sex, diffuse-type GC was more common in younger patients, and the proportion of intestinal-type GC increased with age. The overall survival rate was significantly higher in females (P < 0.001). However, this difference disappeared for GC-specific survival (P = 0.168), except for the poor GC-specific survival rate in advanced-stage cancer (stage III or above) in females (P = 0.045). The risk factors for GC-related mortality were older age, upper location of GC, and diffuse- or mixed-type histology. In terms of comorbidities, more males died from diseases other than GC, including other malignancies such as lung cancer, hepatocellular carcinoma, and pancreatic cancer, and respiratory diseases such as interstitial lung disease and chronic obstructive pulmonary disease, while there were relatively more cardiovascular or cerebrovascular deaths in females.

CONCLUSION

Sex-based differences in GC were observed in clinicopathological features, including age at diagnosis, tumor location, histologic type, survival rate, and comorbidities.

ABHD11-AS1: An Emerging Long Non-Coding RNA (lncRNA) with Clinical Significance in Human Malignancies

The aberrant expression of lncRNAs has been linked to the development and progression of different cancers. One such lncRNA is ABHD11 antisense RNA 1 (ABHD11-AS1), which has recently gained attention for its significant role in human malignancies. ABHD11-AS1 is highly expressed in gastric, lung, breast, colorectal, thyroid, pancreas, ovary, endometrium, cervix, and bladder cancers. Several reports highlighted the clinical significance of ABHD11-AS1 in prognosis, diagnosis, prediction of cancer progression stage, and treatment response. Significantly, the levels of ABHD11-AS1 in gastric juice had been exhibited as a clinical biomarker for the assessment of gastric cancer, while its serum levels have prognostic potential in thyroid cancers. The ABHD11-AS1 has been reported to exert oncogenic effects by sponging different microRNAs (miRNAs), altering signaling pathways such as PI3K/Akt, epigenetic mechanisms, and N6-methyladenosine (m⁶A) RNA modification. In contrast, the mouse homolog of AHD11-AS1 (Abhd11os) overexpression had exhibited neuroprotective effects against mutant huntingtin-induced toxicity. Considering the emerging research reports, the authors attempted in this first review on ABHD11-AS1 to summarize and highlight its oncogenic potential and clinical significance in different human cancers. Lastly, we underlined the necessity for future mechanistic studies to unravel the role of ABHD11-AS1 in tumor development, prognosis, progression, and targeted therapeutic approaches.

Assessment of the short-term outcomes of laparoscopic gastrectomy after neoadjuvant chemotherapy for locally advanced gastric cancer: A prospective single-armed clinical trial

BACKGROUND

Laparoscopic surgical approaches for gastric cancer after neoadjuvant chemotherapy are increasing, yet there is limited evidence of their safety and effectiveness.

METHODS

This prospective single-armed clinical trial enrolled 80 neoadjuvant chemotherapy patients who underwent laparoscopic gastrectomy. In addition, to better analyze the outcomes of this study, 1:2 propensity score matching was performed, and a contemporaneous historic control group containing 160 laparoscopic gastrectomy patients without neoadjuvant chemotherapy was established.

RESULTS

Analyses were performed to compare the neoadjuvant chemotherapy group (n = 80) and the control group (n = 160). The general clinical data of both groups were comparable. The neoadjuvant chemotherapy group showed less intraoperative bleeding (P = .029) and recovered more quickly than the control group (all P < .05). The 2 groups did not exhibit major differences in terms of postoperative complications (P = .679) or severe complications (P = .055). The proportion of patients with ypT4 stage and ypN3 stage disease in the neoadjuvant chemotherapy group totaled 20.7% and 23.8%, respectively, which was significantly lower than that observed in the control group (P < .05). The number of metastatic lymph nodes was 4.8 ± 7.0 in the neoadjuvant chemotherapy group, which was lower than that in the control group (P < .001). In the neoadjuvant chemotherapy group, the major pathological regression rate was 27.5%, while the objective radiologic response rate (complete response + partial response) was 64.0%. In contrast to nonresponding patients, the patients who experienced an objective response had a shorter operation time (P < .001), less intraoperative bleeding (P < .001), and fewer metastatic lymph nodes (P = .005). The short-term effects observed in the nonresponding patients were similar to those observed in the control group.

CONCLUSION

Laparoscopic gastrectomy could achieve improved short-term outcomes through NACT tumor downstaging without increasing the incidence of postoperative complications. Further multicenter and prospective clinical trials are warranted.

CDH1 Germline Variants in a Tunisian Cohort with Hereditary Diffuse Gastric Carcinoma

Mutational screening of the CDH1 gene is a standard treatment for patients who fulfill Hereditary Diffuse Gastric Cancer (HDGC) testing criteria. In this framework, the classification of variants found in this gene is a crucial step for the clinical management of patients at high risk for HDGC. The aim of our study was to identify CDH1 as well as CTNNA1 mutational profiles predisposing to HDGC in Tunisia. Thirty-four cases were included for this purpose. We performed Sanger sequencing for the entire coding region of both genes and MLPA (Multiplex Ligation Probe Amplification) assays to investigate large rearrangements of the CDH1 gene. As a result, three cases, all with the HDGC inclusion criteria (8.82% of the entire cohort), carried pathogenic and likely pathogenic variants of the CDH1 gene. These variants involve a novel splicing alteration, a missense c.2281G > A detected by Sanger sequencing, and a large rearrangement detected by MLPA. No pathogenic CTNNA1 variants were found. The large rearrangement is clearly pathogenic, implicating a large deletion of two exons. The novel splicing variant creates a cryptic site. The missense variant is a VUS (Variant with Uncertain Significance). With ACMG (American College of Medical Genetics and Genomics) classification and the evidence available, we thus suggest a revision of its status to likely pathogenic. Further functional studies or cosegregation analysis should be performed to confirm its pathogenicity. In addition, molecular exploration will be needed to understand the etiology of the other CDH1- and CTNNA1-negative cases fulfilling the HDGC inclusion criteria.

Helicobacter pylori Prevalence and Risk Factors in Three Rural Indigenous Communities of Northern Arizona

Helicobacter pylori (H. pylori) is one of the most common bacterial stomach infections and is implicated in a majority of non-cardia gastric cancer. While gastric cancer has decreased in the United States (US), the incidence in the Navajo Nation is nearly four times higher than surrounding Non-Hispanic White populations. Little is known about H. pylori prevalence in this population or other Indigenous communities in the lower 48 states. In this cross-sectional study, 101 adults representing 73 households from three Navajo Nation chapter communities completed surveys and a urea breath test for active H. pylori. Accounting for intrahousehold correlation, H. pylori prevalence was 56.4% (95% CI, 45.4–66.8) and 72% of households had at least one infected person. The odds of having an active infection in households using unregulated water were 8.85 (95% CI, 1.50–53.38) that of the use of regulated water, and males had 3.26 (95% CI, 1.05–10.07) higher odds than female. The prevalence of H. pylori in Navajo is similar to that seen in Alaska Natives. Further investigation into factors associated with prevention of infection is needed as well as understanding barriers to screening and treatment.

Epstein-Barr Virus-Associated Gastric Cancer: Old Entity with New Relevance

Gastric cancer (GC) represents a major public health issue worldwide, being the fifth most common cancer and one of the leading causes of death by cancer. In 2014, The Cancer Genome Atlas (TCGA) established that tumors positive for Epstein-Barr virus (EBV) are considered a specific subtype of GC (EBVaGC). Several meta-analyses have shown that EBVaGC represents almost 10% of all gastric cancer worldwide, with small differences in the geographic distribution. This tumor subtype has a high potential of being clinically relevant and studies have shown that it has specific features, a better prognosis, and increased overall survival. In this review, we summarize some of the most frequent aspects of EBVaGC, including the specific features of this GC subtype, data regarding the potential steps of EBVaGC carcinogenesis, and perspectives on treatment opportunities.

The dual role of microRNA-9 in gastrointestinal cancers: oncomiR or tumor suppressor?

microRNA are noncoding endogenous RNAs of ∼ 25-nucleotide, involved in RNA silencing and controlling of cell function. Recent evidence has highlighted the important role of various in the biology of human cancers. miR-9 is a highly conserved microRNA and abnormal regulation of miR-9 expression has various impacts on disease pathology. miR-9 may play a dual tumor-suppressive or oncomiR activity in several cancers. There have been conflicting reports concerning the role of miR-9 in gastrointestinal cancers. Several signaling pathways including PDK/AKT, Hippo, Wnt/β-catenin and PDGFRB axes are affected by miR-9 in suppressing proliferation, invasion and metastasis of tumor cells. Oncogenic miR-9 triggers migration, metastasis and clinic-pathological characteristics of patients with gastrointestinal malignancy by targeting various enzymes and transcription factors such as E-cadherin, HK2, LMX1A, and CDX2. On the other hand, long non-coding RNAs and circular RNAs can modulate miR-9 expression in human cancers. In this review, we aimed to summarize recent findings about the potential value of miR-9 in gastrointestinal tumors, that include: screening, prognostic and treatment.

Secular decreasing trends in gastric cancer incidence in Taiwan: A population-based cancer registry study

BACKGROUND

Gastric cancer remains a leading cause of cancer death worldwide. In Taiwan, gastric cancer is the sixth leading cause of cancer mortality in both males and females.

AIM

To evaluate secular trends in gastric cancer incidence according to age, sex, and Helicobacter pylori (H. pylori) treatment in Taiwan.

METHODS

In this population-based study, we used the national Taiwan Cancer Registry database. Annual percent changes in incidence rates were used to describe secular trends in incidence rates and sex ratios of gastric cancer in Taiwan. Pearson’s product-moment correlation coefficients were used to analyze the correlation between annual age-adjusted incidence rates and the annual number of patients treated with antibiotic therapy for H. pylori infection.

RESULTS

The annual percent changes showed continuously decreasing rates of gastric cancer among both males and females. However, the decreasing trends differed by sex, with an annual percent change of -2.58% in males and -2.14% in females. The age-specific incidence rates increased with age. Within the same age group, more recent time periods showed lower incidence rates than greater time periods. Similarly, the sex ratio was lower in later birth cohorts than in earlier birth cohorts. Age-adjusted incidence rates substantially decreased with increasing numbers of patients being treated with antibiotic therapy for H. pylori infection during 2005 to 2016 (r = 0.72).

CONCLUSION

We observed steadily decreasing trends with differential sex ratios in the incidence of gastric cancer in Taiwan. These results support H. pylori eradication programs in Taiwan.

A Case Study on Modeling the Time to Recurrence of Gastric Cancer Patients

BACKGROUND

Gastric cancer is a malignant tumor of the stomach and it is one of the leading causes of death worldwide. The study aimed to model the time to first recurrence of gastric cancer patients at the Tikur Anbesa specialized hospital.

METHODS

The data for this study were gastric cancer patients followed up from January 1, 2013 to February 29, 2020 at Tikur Anbesa Specialized Hospital, Oncology Center, Addis Ababa. We used Weibull, log-logistic and lognormal as baseline hazard functions with the gamma and the inverse Gaussian frailty distributions. Data analyzed with the statistical software R.

RESULTS

The median recurrence time of the patients was about 23.96 months with a maximum recurrence time of 60.81 months, of which about 61.2% had first recurrences of gastric cancer. The clustering effect is significant in modeling the time to recurrence of gastric cancer. According to the result of the log-logistic inverse Gaussian frailty model, the sex of the patient, the tumor size, smoking habit, the treatment carried out, the vascular invasion, the stage of the disease, the helicobacter pylori infection and the histological type were the significant prognostic factors  at 5% level of significance.

CONCLUSION

Inverse Gaussian frailty model is the model that best describes the time to recurrence of the gastric cancer data set. Gender of the patients, tumor size, treatment taken, vascular invasion, disease stage, helicobacter pylori infection and histological type were the determining prognostic factors. This requires measures to improve patient health and prevent relapse based on significant risk factors, and particular attention should be paid to patients with such factors.

Increased Risk of Gastric Cancer in Asbestos-Exposed Workers: A Retrospective Cohort Study Based on Taiwan Cancer Registry 1980-2015

Asbestos has been recognized as a human carcinogen associated with malignant mesothelioma, cancers of lung, larynx, and ovary. However, a putative association between gastric cancer and asbestos exposure remains controversial. In this study, we aimed to explore gastric cancer risk of workers potentially exposed to asbestos in Taiwan. The asbestos occupational cohort was established from 1950 to 2015 based on the Taiwan Labor Insurance Database, and Taiwan Environmental Protection Agency regulatory datasets, followed by the Taiwan Cancer Registry for the period 1980–2015. Standardized incidence ratios (SIRs) for cancer were computed for the whole cohort using reference rates of the general population, and also reference labor population. Compared with the general population, SIR of the asbestos occupational cohort for the gastric cancer increased both in males (1.05, 95% confidence interval (CI): 1.02–1.09) and females (1.10, 95% CI: 1.01–1.18). A total of 123 worksites were identified to have cases of malignant mesothelioma, where increased risk for gastric cancer was found with a relative risk of 1.76 (95% CI: 1.63–1.90). This 35-year retrospective cohort study of asbestos-exposed workers in Taiwan may provide support for an association between occupational exposure to asbestos and gastric cancer.

Metformin and Gastrointestinal Cancer Development in Newly Diagnosed Type 2 Diabetes: A Population-Based Study in Korea

INTRODUCTION

Clinical studies have produced conflicting results on the effects of metformin on gastrointestinal cancer development. We aimed to investigate the association between metformin use and stomach, colon, liver, and pancreatic cancer development among patients with newly diagnosed, drug-naïve type 2 diabetes.

METHODS

This retrospective study evaluated propensity score-matched patients with newly diagnosed type 2 diabetes from the Korean National Health Insurance Service database. Metformin users were categorized into tertiles according to the cumulative dose or duration of metformin treatment, and the risks of gastrointestinal cancers were compared.

RESULTS

Metformin users had reduced risks of developing stomach cancer (hazard ratio [HR]: 0.841, 95% confidence interval [CI]: 0.797-0.887), colon cancer (HR: 0.865, 95% CI: 0.822-0.91), and liver cancer (HR: 0.709, 95% CI: 0.675-0.746; P < 0.001). However, metformin users did not have a reduced overall risk of pancreatic cancer (HR: 1.335, 95% CI: 1.209-1.475; P < 0.001). The risks tended to decrease at higher cumulative doses and durations of metformin use, with significantly reduced risks of all 4 cancers at the highest cumulative dose (≥1,200,000 mg) and the longest duration (≥2,000 days) of metformin use.

DISCUSSION

This population-based data suggest that metformin could be associated with reductions in the risks of stomach, colon, and liver cancers, as well a reduced risk of pancreatic cancer in some subgroups. Metformin has benefit as a first-line treatment for type 2 diabetes mellitus. A further role in cancer risk reduction could be studied in controlled trials.

Risk of esophageal and gastric adenocarcinoma in men receiving androgen deprivation therapy for prostate cancer

The aim of this study was to explore the male predominance in esophageal and gastric adenocarcinoma by evaluating the preventive potential of androgen deprivation therapy (ADT). This matched cohort study was based on a national Swedish database of prostate cancer patients in 2006-2013. Prostate cancer patients receiving ADT were the exposed group. Prostate cancer-free men from the general population were randomly selected and matched to the index case by birth year and county of residence, forming the unexposed control group. The participants were followed until a diagnosis of esophageal or gastric cancer, death, emigration, or end of the study period. The risk of esophageal adenocarcinoma, cardia gastric adenocarcinoma, non-cardia gastric adenocarcinoma, and esophageal squamous-cell carcinoma among ADT-exposed compared to unexposed was calculated by multivariable Cox proportional hazard regression. The hazard ratios (HRs) and 95% confidence intervals (CIs) were adjusted for confounders. There was a risk reduction of non-cardia gastric adenocarcinoma among ADT-users compared to non-users (HR 0.49 [95% CI 0.24-0.98]). No such decreased risk was found for esophageal adenocarcinoma (HR 1.17 [95% CI 0.60-2.32]), cardia gastric adenocarcinoma (HR 0.99 [95% CI 0.40-2.46]), or esophageal squamous cell carcinoma (HR 0.99 [95% CI 0.31-3.13]). This study indicates that androgen deprivation therapy decreases the risk of non-cardia gastric adenocarcinoma, while no decreased risk was found for esophageal adenocarcinoma, cardia gastric adenocarcinoma, or esophageal squamous-cell carcinoma.

Circular RNA hsa_circ_0000117 accelerates the proliferation and invasion of gastric cancer cells by regulating the microRNA-337-3p/signal transducer and activator of transcription 3 axis

Circular RNA hsa_circ_0000117 is reportedly increased in Gastric cancer (GC), however, its role is unexplored. Hsa_circ_0000117 expression and function in GC was investigated using standard cell phenotypic and expression assays. Pull-down and luciferase reporter assays also elucidated hsa_circ_0000117 mechanisms. In the present study, we observed increased hsa_circ_0000117 and signal transducer and activator of transcription 3 (STAT3) expression, while microRNA-337-3p (miR-337-3p) was decreased in GC cells. Depleted hsa_circ_0000117 decreased GC proliferation and invasion. Hsa_circ_0000117 was also identified as a miR-337-3p sponge. Also, STAT3 was identified as a miR-337-3p target. Similarly, rescue assays indicated STAT3 overexpression (or miR-337-3p inhibition) reversed hsa_circ_0000117 effects in GC progression. Thus, our data suggested hsa_circ_0000117 exhibited oncogene properties in combination with the hsa_circ_0000117/miR-337-3p/STAT3 axis in GC, potentially providing a new therapeutic target for GC.

Abbreviations GC: gastric cancer; STAT3: Signal transducer and activator of transcription 3; circRNA: Circular RNA; miRNA: microRNA; DMEM: Dulbecco’s modified Eagle’s medium; FBS: fetal bovine serum; PVDF: polyvinylidene fluoride; CCK-8: Cell counting kit-8; qRT-PCR: Quantitative real-time PCR; SDS-PAGE: sodium dodecyl sulfate polyacrylamide gel electrophoresis; TNM: TNM Classification of Malignant Tumors; mTOR: mechanistic target of rapamycin; ANOVA: one-way analysis of variance

CDH1 gene rs1801552 C/T polymorphism increases susceptibility to esophageal squamous cell carcinoma but not to gastric cardiac adenocarcinoma

PURPOSE

The present study aimed to investigate whether the single nucleotide polymorphism (SNP) rs1801552 C/T in CDH1 gene is correlated with the risk of esophageal squamous cell carcinoma (ESCC) and gastric cardiac adenocarcinoma (GCA), as a preliminary study.

METHODS

The rs1801552 C/T polymorphism was genotyped by the method of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 1316 cancer patients (810 ESCC and 506 GCA) and 1966 controls in north China. We performed two case-control studies, each of which included a population-based set and a hospital-based set.

RESULTS

The data showed that the rs1801552 C/T polymorphism was associated with the risk of ESCC. Allelotype and genotype distributions of the rs1801552 C/T polymorphism in ESCC patients of high-incidence region and hospital were significantly different from that in their respective controls (P < 0.05). Compared with C/C genotype, T/T genotype increased the risk of ESCC in high-incidence region and hospital (age, sex, smoking status and family history of UGIC adjusted odds ratio (OR) = 1.79 and 2.10, 95% confidence interval (CI) = 1.23 - 2.60 and 1.10 - 4.04, respectively). Allelotype and genotype distributions of the rs1801552 C/T polymorphism in GCA patients were not significantly different from that in their controls, respectively (P > 0.05).

CONCLUSIONS

The findings in the present pilot study suggest that the rs1801552 C/T polymorphism was associated with the risk of ESCC, but was not associated with the risk of GCA in high-incidence region and hospital.

Targeting nutrient metabolism with FDA-approved drugs for cancer chemoprevention: Drugs and mechanisms

Proliferating cancer cells exhibit metabolic alterations and specific nutritional needs for adapting to their rapid growth. These changes include using aerobic glycolysis, lipid metabolic disorder, and irregular protein degradation. It may be useful to target metabolic abnormalities for cancer chemoprevention. Epidemiological and mechanism-related studies have indicated that many FDA-approved anti-metabolic drugs decrease tumor risk, inhibit tumor growth, or enhance the effect of chemotherapeutic drugs. Drugs targeting nutrient metabolism have fewer side effects with long-term use compared to chemotherapeutic drugs. The characteristics of these drugs make them promising candidates for cancer chemoprevention. Here, we summarize recent discoveries of the chemo-preventive effects of drugs targeting nutrient metabolic pathways and discuss future applications and challenges. Understanding the effects and mechanisms of anti-metabolic drugs in cancer has important implications for exploring strategies for cancer chemoprevention.

Características sociodemográficas e histopatológicas en pacientes con cáncer gástrico en una población con alto riesgo en Colombia

Objetivo: describir las características sociodemográficas e histopatológicas en pacientes con diagnóstico de adenocarcinoma gástrico en la Clínica Oncológica Aurora, durante el período 2014-2017 en la ciudad de Pasto, Colombia. Métodos: se realizó un estudio descriptivo en una cohorte de 54 pacientes con diagnóstico de cáncer gástrico sometidos a gastrectomía durante los años 2014 a 2017. La información sociodemográfica se obtuvo a través de la historia clínica. El sistema de Sydney y la clasificación de Lauren se usaron para determinar las características histopatológicas. Resultados: la mayoría de los tumores se presentó en hombres mayores de 50 años (relación hombre mujer de 2,6:1). La ubicación predominante fue la región antropilórica. El histotipo tumoral más frecuente fue el intestinal (80 %). La prevalencia de Helicobacter pylori en pacientes fue del 24,07 % y fue mayor en el histotipo intestinal. La metaplasia intestinal fue la lesión premaligna más prevalente en todos los histotipos tumorales. Conclusiones: en el presente estudio se encontró que la edad mayor a 50 años y el sexo masculino son condiciones asociadas con el cáncer gástrico; hallazgo ya demostrado en estudios previos. Es perentorio avanzar en el mejoramiento de las condiciones de salud pública, control de la infección por H. pylori y tamizaje temprano de lesiones premalignas, pues son factores determinantes en la carcinogénesis de pacientes con carcinomas no cardiales e histotipos intestinales ubicados en la región antrocorporal. Aunque no se encontraron diferencias significativas entre los histotipos tumorales, el adenocarcinoma de tipo intestinal ubicado en la región antropilórica fue el diagnóstico más frecuente.

Gastric Cancer Among American Indian and Alaska Native Populations in the United States, 2005-2016

INTRODUCTION

American Indian and Alaska Native (AI/AN) populations have higher gastric cancer rates than the general US population. This study provides a comprehensive overview of incidence rates among AI/AN persons during 2005-2016 compared with non-Hispanic whites (whites).

METHODS

Population-based cancer registry data for 2005-2016 were linked with the Indian Health Service patient registration databases to address racial misclassification. Age-adjusted gastric cancer incidence rates were expressed per 100,000 per year. Incidence and trend analyses were restricted to purchased/referred care delivery area counties in 6 geographic regions, comparing gastric cancer incidence rates for AI/AN vs white populations in the United States.

RESULTS

Gastric cancer rates were higher in the AI/AN compared with white populations in nearly every US region. Incidence rates for central/distal portions of the stomach were higher in AI/AN individuals compared with whites. Rates of later stage gastric cancer were higher in AI/AN populations overall and in every region except the Pacific Coast and East. Incidence rates decreased significantly over time in both populations. Declining rates in the AI/AN populations were driven by changes in the Pacific Coast and Northern Plains regions.

DISCUSSION

AI/AN populations have a disproportionately high incidence of gastric cancer, especially in Alaska. High incidence in the central/distal portions of the stomach among AI/AN populations likely reflects a high prevalence of Helicobacter pylori infection in these populations. These data can be used to develop interventions to reduce risk factors and improve access to health services among AI/AN people at high risk for gastric cancer.

Prognostic value of a new staging system based on the retrieved number and metastatic rate of LNs in gastric cancer with ≤15 retrieved LNs

OBJECTIVE

To investigate a reasonable lymph node (N) staging system for gastric cancer patients with ≤15 retrieved lymph nodes (LNs).

METHODS

The clinicopathological and follow-up data of patients with ≤15 LNs were obtained from the US Surveillance, Epidemiology, and End Results (SEER) database to analyze the impact of the number of retrieved LNs and metastatic status on the prognosis. In addition, external validation was achieved with data from two medical centers in China.

RESULTS

A total of 18,139 gastric cancer patients with 1-15 retrieved LNs from the SEER database were enrolled and randomly divided into the training group and the internal validation group. A new LN staging system, mNr staging (mNr0-4; 5 stages), was established according to the number of retrieved LNs and the metastatic rate. Compared with the TNM and TNrM staging systems (established by Wang J; misclassification rates of 50.4% and 62.5%, respectively), the mTNrM staging system had a lower misclassification rate (23.4%). Furthermore, there was a significant difference in the 5-year overall survival (OS) rate between the mTNrM staging subgroups (p < 0.05); however, no significant difference was found in the 5-year OS rate of partial adjacent stages in the TNM (8th edition) and TNrM (p > 0.05) staging systems. Similar results were obtained in the external validation cohort.

CONCLUSION

mNr and mTNrM staging systems can efficiently distinguish a survival difference in patients who undergo gastrectomy with ≤15 retrieved LNs, with more accurate predictions of the 5-year OS rate of patients compared with the TNM and TNrM staging systems.

Long non-coding RNA ZFAS1 promotes the expression of EPAS1 in gastric cardia adenocarcinoma

LncRNA (Long non-coding RNA) ZFAS1 (zinc finger antisense 1) functions as the oncogene in multiple cancers, including gastric cancer. However, its function and underlying mechanism in the GCA (gastric cardia adenocarcinoma), the most aggressive type of gastric cancer, remain unknown. We demonstrated here that the LncRNA ZFAS1 was up-regulated in GCA tissues. Furthermore, the elevated level of ZFAS1 was significantly associated with the GCA metastasis and cancer recurrence. It was also demonstrated to be an independent prognostic indicator of disease-free survival and overall survival for GCA patients. RNA sequencing showed that the up-regulated ZFAS1 was tightly associated with the down-regulated hypoxia inducible factor 1 (HIF1) and up-regulated EPAS1 (Endothelial PAS domain protein 1, also known as HIF2). In vitro studies showed that the ZFAS1 could bind to EPAS1, enhance its abilities to epigenetically silence the HIF1, and promote its own expression in GCA cell lines. In the animal model, co-delivering the EPAS1 and the ZFAS1 antisense oligos could significantly boost up their therapeutic effects on tumor growth. Thus, targeting ZFAS1 and EPAS1 might be an alternative therapeutic option in GCA.

Increased risk for uterine cancer among first-degree relatives to Swedish gastric cancer patients

Purpose

In order to further understand genetically predisposing factors of gastric cancer, a retrospective study on 107 patients with gastric cancer was conducted. The family history of cancer cases was registered, in search of associations between gastric cancer and other cancer types.

Materials and methods

Within Stockholm County in Sweden, all patients previously diagnosed with gastric cancer and still alive were invited to participate in the study. Patients were asked to complete a questionnaire about their gastric cancer diagnosis and if any cancers had occurred in their family. A blood sample for DNA extraction was collected. The proportions of different cancer types in the relatives of the patients were compared to the general Swedish population in 1970 and 2010.

Results

Among first- and second-degree relatives to the index patients with gastric cancer, the frequency of uterine cancer as well as gastric cancer was significantly overrepresented compared to the general population in Sweden. The frequency of breast cancer was significantly lower.

Conclusions

There seems to be an increased risk of both gastric cancer and uterine cancer in the families of gastric cancer survivors, indicating a possible hereditary connection between these two cancer types.

Genetic variations associated with telomere length affect the risk of gastric carcinoma

This study aimed to further understand the role of relative telomere length (RTL) in susceptibility to gastric carcinoma (GC) and investigate the association between genetic polymorphisms in the telomere length related genes and GC risk.RTL was measured using the real-time quantitative polymerase chain reaction from 1000 patients and 1100 healthy controls. Genotyping was performed using the Agena MassARRAY platform. The statistical analysis was performed using the chi-square/ Welch T tests, Mann-Whitney U test, and logistic regression analysis.The association analysis of telomere length and GC showed that the RTL in the case group was shorter than in the controls, and the shorter RTL was associated with an increased risk of GC. The association analysis between telomere length related genes polymorphisms and genetic susceptibility to GC indicated that: In the allele models and genetic models, TERT (rs10069690, rs2242652 and rs2853676) and TN1F1 (rs7708392 and rs10036748) were significantly associated with an increased risk of GC. In addition, the haplotype 'Grs10069690Crs2242652" of TERT and the haplotype 'Grs7708392Trs10036748" of TNIP1 were associated with an increased risk of GCOur results suggested that shorter RTL was associated with an increased risk of GC; The association analysis have identified that the TERT (rs10069690, rs2242652 and rs2853676) and TN1P1 (rs7708392 and rs10036748) were associated with GC risk.

Assessment of hydrogeochemical characteristics and quality of groundwater resources in relation to risk of gastric cancer: comparative analysis of high- and low-risk areas in Iran

The chemical quality of groundwater supplies in two high-risk area (HRA) and low-risk area (LRA) for gastric cancer in Iran was assessed through hydrogeochemical analysis and water quality indices. For this aim, Piper and Schoeller diagrams and water quality index (WQI) were applied. In addition, exposure to nitrate via drinking water and its corresponding risk were also assessed using Monte Carlo simulation technique. Data on physicochemical properties of groundwater resources were obtained from Iran Water Resources Management Company. Sampling and analysis of tap water for nitrate concentration were conducted in two cities of Shiraz (as a representative of LRA) and Ardabil (as a representative of HRA). According to Piper diagrams, the dominant hydrogeochemical facies of groundwater supplies in HRA and LRA were Na-HCO₃ (43.75%) and Ca-HCO₃ (41.77%), respectively. The predominant cations in groundwater resources of HRA were found to be Na⁺ (68.06%) and Ca²⁺ (31.94%). For LRA, the typical cations were in decreasing trend: Ca²⁺ (39.64%) > Mg²⁺ (18.35%) > Na⁺ (17.26%). For two areas, HCO₃^-, SO₄^2- and Cl^- were, respectively, the most frequent anions. Two-sample Wilcoxon test showed that there were statistically significant difference between two areas in terms of anions and cations concentrations (p value < 0.05). The mean of total hardness (Ca²⁺ + Mg²⁺) concentration of water supplies in LRA (528.1 mg/L) was higher than HRA (263.1 mg/L), whereas the mean of Na⁺ concentration was found to be lower in LRA (90.6 mg/L) compared with HRA (108.1 mg/L). The sum of nitrate intake and its risk in LRA was higher than HRA. WQI results showed that drinking water quality in HRA and LRA ranged from excellent to poor and most water resources were of a good quality class. Further studies are suggested to investigate the role of drinking water in the etiology of gastric cancer in Iran.

Epigenetically silenced PD-L1 confers drug resistance to anti-PD1 therapy in gastric cardia adenocarcinoma

OBJECTIVES

The anti-PD-1/PD-L1 therapy has been demonstrated safe and effective for cancer patients. However, our previous data showed that it had no obvious effects on gastric cardia adenocarcinoma (GCA). Thus, we investigated how the expression level of the PD-L1 was affected by the anti-PD-1 therapy, because it has been demonstrated that the PD-L1 level affects the therapeutic efficient of the anti-PD-1 therapy.

MATERIALS AND METHODS

The mRNA and protein levels of PD-L1 in the GCA tissues and corresponding normal tissues were determined by qPCR and ELISA. Promoter methylation was analyzed by bisulfite sequencing. Finally the methylation of PD-L1 promoter was confirmed in the mice.

RESULTS

The level of PD-L1 was up-regulated in the GCA tissues when compared to the adjacent non-tumor tissues. The anti-PD1 therapy could reduce the PD-L1 levels in patients with cancer recurrence. The promoter of PD-L1 was more hypermethylated in the secondary GCA after the anti-PD-1 therapy when compared with the adjacent non-tumor tissues or the primary GCA without the anti-PD-1 therapy. Furthermore, the promoter methylation of PD-L1 could be induced by the anti-PD-1 therapy in the mice model. Finally, the anti-PD-1 plus DNA hypomethylating agent azacytidine could significantly suppressed the tumor growth better than the anti-PD-1 therapy.

CONCLUSIONS

Here we demonstrated that the unresponsiveness of GCA to the anti-PD-1 therapy might result from the promoter methylation and down-regulation of PD-L1. The anti-PD-1 plus azacytidine might be a more promising approach to treat GCA.

Clinical Evaluation of Serum Tumor Markers in the Diagnosis of Gastric Adenocarcinoma Staging and Grading

ᅟ: Detection and quantitative measurements of diffused tumor markers in blood samples of patients with cancer is a facile and convenient method to determine prognosis and the appropriateness of the treatment. This study was done to evaluate the level of CA125, CEA, AFP, Beta HCG, and CA19-9 tumor markers and their relation to the stage and grade of the disease in patients with gastric adenocarcinoma.

MATERIALS AND METHODS

In a descriptive cross-sectional study, of 81 patients referred to the oncology department of Tohid Hospital, Sanandaj, Iran, in 1 year, with recently detected gastric adenocarcinoma, serum level of CEA, CA19-9, CA125, AFP, and Beta HCG tumor markers was measured by ELISA method before chemotherapy and surgery. Patients were divided into four groups based on stage of disease (I, II, III, IV), and in terms of tumor differentiation, degrees were classified in to three groups: low, high, and intermediate. To determine the correlation of tumor markers level with the stage and grade of the disease, the Kruskal-Wallis and Mann-Whitney U tests were used.

RESULTS

By progression, the stages of the disease, the serum level of CA19-9, CA125, and AFP tumor markers demonstrated a significant increase. But this difference between level of HCG and CEA was not significant with the staging. There was no significant difference between the serum level of tumor markers and the grading of disease in the patients.

CONCLUSION

Preoperative CA19-9, CA125, and AFP tumor markers measurements could be beneficial in detecting the progressed stages of the disease.

RRAD expression in gastric and colorectal cancer with peritoneal carcinomatosis

The role of Ras-related associated with diabetes (RRAD) in gastric cancer (GC) or colorectal cancer (CRC) has not been investigated. We aimed to investigate the biological and clinical roles of RRAD in GC and CRC and to assess RRAD as a therapeutic target. A total of 31 cancer cell lines (17 GC cell lines, 14 CRC cell lines), 59 patient-derived cells (PDCs from 48 GC patients and 11 CRC patients), and 84 matched pairs of primary cancer tissue and non-tumor tissue were used to evaluate the role of RRAD in vitro and in vivo. RRAD expression was frequently increased in GC and CRC cell lines, and siRNA/shRNA-mediated RRAD inhibition induced significant decline of tumor cell proliferation both in vitro and in vivo. A synergistic effect of RRAD inhibition was generated by combined treatment with chemotherapy. Notably, RRAD expression was markedly increased in PDCs, and RRAD inhibition suppressed PDC proliferation. RRAD inhibition also resulted in reduced cell invasion, decreased expression of EMT markers, and decreased angiogenesis and levels of associated proteins including VEGF and ANGP2. Our study suggests that RRAD could be a novel therapeutic target for treatment of GC and CRC, especially in patients with peritoneal seeding.

Predictive Factors for Lymph Node Metastasis and the Effect on Survival in Early Gastric Cancer Patients with Radical Gastric Resection

Objectives

Selected patients with early gastric cancer (GC) are treated endoscopically. Lymph node metastasis (LNM) in the T1 stage may also be detected during surgical resection for early GC. The aim of this study was to determine factors associated with LNM and the effect on survival.

Methods

A total of 63 patients with tumor invasion stage T1a or T1b who were operated on for early GC between 2010 and 2018 were included in the study. Parameters were investigated retrospectively to identify predictive factors for LNM and overall survival. Significance was defined with a 2-sided p-value of <0.05.

Results

Among the 63 patients, 21 (33.3%) had LNM. Lymphovascular invasion (LVI) (p=0.02) and a high-grade tumor (p=0.02) were significantly associated with LNM. The overall survival rate was 73.0%. The number of patients with LNM was greater among the deceased patients compared with the censored group (p=0.03). The median follow-up time of the entire group was 28 months (range: 12-55 months) while it was 23 months (range: 7-39 months) in the deceased group and 33.5 months (15.5-60 months) in the censored group (p=0.06). The mean survival was 62.36 months in patients with LNM and 71.99 months in those without LNM (p=0.09). The cut-off value determined for the neutrophil-to-lymphocyte ratio (NLR) was 2.33 and it was an effective value in survival analysis (p<0.05).

Conclusion

Surgical treatment should be considered for early GC patients with high-grade tumors and cases demonstrating LVI. The overall survival was shorter in patients with a high NLR value and LNM.

Time Trends And Age-Period-Cohort Effects On The Incidence Of Gastric Cancer In Changle From 2003 To 2012

Purpose

Although the incidence of gastric cancer in China has declined over the past decades, they were still much higher than the average of global. This aim of this study was to describe the trends and age-period-cohort effects on gastric cancer incidence from 2003 to 2012 in Changle and to explore the potential reason.

Materials and methods

Data on patients with gastric cancer diagnosed between 2003 and 2012 were collected by the population-based Changle cancer registration (n=4111). Age-standardized incidence rates of gastric cancer were calculated and joinpoint regression was used to evaluate the trends of gastric cancer incidence. Time trends in gastric cancer incidence by the period of diagnosis and birth cohort were analyzed by sex. Age-period-cohort analysis was performed to investigate the independent effects of age, period of diagnosis and birth cohort among over 25-year-old residents.

Results

A steady downward trend was observed among men, with the incidence ranging from 96.15 per 100,000 in 2003 to 62.6 per 100,000 in 2012 (APC, −5.1%; 95% CI: −6.9 to −3.2%). A similarly declining trend was observed among women with the incidence ranging from 34.5 per 100,000 to 15.7 per 100,000 (APC, −5.7%; 95% CI: −9.3 to −2.0%). Age-period-cohort model of incidence rate showed increasing age effect and decreasing period of diagnosis effects in both men and women. Birth cohorts exhibited a decreasing trend in the incidence among women who were born after 1935 and men after 1940.

Conclusion

Recent decreases in the incidence of gastric cancer were due to decreased period of diagnosis and cohort effects, which was attributed to the improvements in their lifestyle and habits.

Association between selenium, cadmium, and arsenic levels and genetic polymorphisms in DNA repair genes (XRCC5, XRCC6) in gastric cancerous and non-cancerous tissue

Gastric cancer is one of the most prevalent cancers in northern Iran. The DNA repair genes X-ray repair cross-complementing (XRCC) group 5, XRCC6, which are important members of non-homologous end-joining repair system, play an important role in repairing the DNA double-strand breaks. Chronic exposure to heavy metals has long been recognized as being capable of augmenting gastric cancer incidence among exposed human populations. Since trace elements could directly or indirectly damage DNA, and polymorphism in DNA DSBs-repair genes can alter the capacity of system repair, we assumed that XRCC5 VNTR and XRCC6-61C >G polymorphism also impress the DSBs-repair system ability and contribute to gastric cancer. Therefore, the objective of this research was to evaluate the tissue accumulation of Selenium (Se), Cadmium (Cd) and Arsenic (As), and XRCC5 VNTR, XRCC6-61C >G polymorphisms in cancerous and non-cancerous tissues in Golestan province. The study population included 46 gastric cancer patients and 43 cancer-free controls. Two polymorphisms of XRCC5, XRCC6 were genotyped using polymerase chain reaction (PCR) or polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Further employed was atomic absorption spectroscopy so as to determine the levels of Se, Cd and As. Finally, the data were analyzed by SPSS (version 16) statistical software. The Se level was significantly higher in tumors as compared to non-tumor tissues, but there was no significant correlation between As and Cd in cancerous and noncancerous tissues. Allele frequencies of the selected genes were not statistically different between groups regarding XRCC6 (-61C>G). XRCC5 0R/0R, 0R/1R, 1R/1R, and 0R/2R genotypes were more common in cancerous group. High levels of Se in cancerous tissues vs. non-cancerous tissues may be one of the carcinogenic factors; in Golestan province, unlike other regions of Iran and the world, the level of Se is high, hence the higher risks of gastric cancer.

Long-Term Outcomes Comparison of Endoscopic Resection With Gastrectomy for Treatment of Early Gastric Cancer: A Systematic Review and Meta-Analysis

Background: Endoscopic resection (ER) and gastrectomy have been both accepted as curative treatments for early gastric cancer. We intended to compare ER with gastrectomy treatments on safety of patients, disease-free survival and overall survival for early gastric cancer through this systematic review. Methods: A literature search was performed in Pubmed, Embase, and Cochrane Library databases. Studies that have compared ER with gastrectomy for early gastric cancer were included in this meta-analysis. We searched for clinical studies published before March 2019. Stata 12.0 software was used for systematic analysis. Results: Nine studies were included in this systematic review, ER treatment was associated with a shorter length of stay (WMD = -8.53, 95% CI -11.56 to -5.49), fewer postoperative complications (OR = 0.47, 95% CI 0.34-0.65). ER can be performed safely with shorter hospital stay and fewer postoperative complications than gastrectomy. Recurrence rate was higher for ER than for gastrectomy treatment (HR = 3.56, 95% CI 1.86-6.84), mainly because metachronous gastric cancers developed only in the ER treatment. However, most of the metachronous gastric cancers could be curatively treated with ER again, and it didn't affect overall survival of patients with early gastric cancer. There was no difference in overall survival rate between ER and gastrectomy (HR = 0.84, 95% CI 0.63-1.13). Conclusions: ER and gastrectomy are both acceptable for curative treatment of early gastric cancer. However, due to the comparable overall survival and lower postoperative complications and shorter length of stay, ER is better than gastrectomy for early gastric cancer, who met the indication for ER treatment.

High Salt Inhibits Tumor Growth by Enhancing Anti-tumor Immunity

Excess salt intake could affect the immune system by shifting the immune cell balance toward a pro-inflammatory state. Since this shift of the immune balance is thought to be beneficial in anti-cancer immunity, we tested the impact of high salt diets on tumor growth in mice. Here we show that high salt significantly inhibited tumor growth in two independent murine tumor transplantation models. Although high salt fed tumor-bearing mice showed alterations in T cell populations, the effect seemed to be largely independent of adaptive immune cells. In contrast, depletion of myeloid-derived suppressor cells (MDSCs) significantly reverted the inhibitory effect on tumor growth. In line with this, high salt conditions almost completely blocked murine MDSC function in vitro. Importantly, similar effects were observed in human MDSCs isolated from cancer patients. Thus, high salt conditions seem to inhibit tumor growth by enabling more pronounced anti-tumor immunity through the functional modulation of MDSCs. Our findings might have critical relevance for cancer immunotherapy.