Panel of significant risk factors predicts early stage gastric cancer and indication of poor prognostic association with pathogens and microsatellite stability

Gastric cancer-Epidemiology, modifiable and non-modifiable risk factors, challenges and opportunities: An updated review

Gastric cancer represents a significant global health challenge due to its high mortality and incidence rates, particularly in Eastern Asia, Eastern Europe, and South America. This comprehensive review synthesizes the latest epidemiological data and explores both modifiable and non-modifiable risk factors associated with gastric cancer, aiming to delineate the multifactorial etiology of this disease. Modifiable risk factors include Helicobacter pylori infection, obesity, dietary habits, smoking and alcohol consumption, whereas nonmodifiable factors comprise genetic predispositions, age, family history and male gender. The interplay of these factors significantly impacts the risk and progression of gastric cancer, suggesting potential preventive strategies. The challenges in treating gastric cancer are considerable, largely because of the late-stage diagnosis and the heterogeneity of the disease, which complicate effective treatment regimens. Current treatment strategies involve a combination of surgery, chemotherapy, radiotherapy, and targeted therapies. The FLOT regimen (5-FU, Leucovorin, Oxaliplatin and Docetaxel) is now a standard for resectable cases in Europe and the US, showing superior survival and response rates over ECF and ECX regimens. For HER2-positive gastric cancer, trastuzumab combined with chemotherapy improves overall survival, as demonstrated by the ToGA trial. Additionally, immune checkpoint inhibitors like pembrolizumab and nivolumab offer promising results. However, the five-year survival rate remains low, underscoring the urgency for improved therapeutic approaches. Recent advancements in molecular biology and cancer genomics have begun to pave the way for personalized medicine in gastric cancer care, focusing on molecular targeted therapies and immunotherapy. This review also highlights the critical need for better screening methods that could facilitate early detection and treatment, potentially improving the prognosis. By integrating epidemiological insights with new therapeutic strategies, this article aims to thoroughly understand of gastric cancer's dynamics and outline a framework for future research and clinical management, advocating for a multidisciplinary approach to tackle this formidable disease.

Risk Prediction Models for Gastric Cancer: A Scoping Review

Background

Gastric cancer is a significant contributor to the global cancer burden. Risk prediction models aim to estimate future risk based on current and past information, and can be utilized for risk stratification in population screening programs for gastric cancer. This review aims to explore the research design of existing models, as well as the methods, variables, and performance of model construction.

Methods

Six databases were searched through to November 4, 2023 to identify appropriate studies. PRISMA extension for scoping reviews and the Arksey and O'Malley framework were followed. Data sources included PubMed, Embase, Web of Science, CNKI, Wanfang, and VIP, focusing on gastric cancer risk prediction model studies.

Results

A total of 29 articles met the inclusion criteria, from which 28 original risk prediction models were identified that met the analysis criteria. The risk prediction model is screened, and the data extracted includes research characteristics, prediction variables selection, model construction methods and evaluation indicators. The area under the curve (AUC) of the models ranged from 0.560 to 0.989, while the C-statistics varied between 0.684 and 0.940. The number of predictor variables is mainly concentrated between 5 to 11. The top 5 most frequently included variables were age, helicobacter pylori (Hp), precancerous lesion, pepsinogen (PG), sex, and smoking. Age and Hp were the most consistently included variables.

Conclusion

This review enhances understanding of current gastric cancer risk prediction research and its future directions. The findings provide a strong scientific basis and technical support for developing more accurate gastric cancer risk models. We expect that these conclusions will point the way for future research and clinical practice in this area to assist in the early prevention and treatment of gastric cancer.

Role of lncRNAs in Helicobacter pylori and Epstein-Barr virus associated gastric cancers

Helicobacter pylori infection is a risk factor for the development of gastric cancer (GC), and the role of co-infection with viruses, such as Epstein-Barr virus, in carcinogenesis cannot be ignored. Furthermore, it is now known that genetic factors such as long non-coding RNAs (lncRNAs) are involved in many diseases, including GC. On the other side, they can also be used as therapeutic goals. Modified lncRNAs can cause aberrant expression of genes encoding proximal proteins, which are essential for the development of carcinoma. In this review, we present the most recent studies on lncRNAs in GC, concentrating on their roles in H. pylori and EBV infections, and discuss some of the molecular mechanisms of these GC-related pathogens. There was also a discussion of the research gaps and future perspectives.

Low incidence of microsatellite instability in gastric cancers and its association with the clinicopathological characteristics: a comparative study

Gastric cancer is a complex heterogeneous disease with different molecular subtypes that have clinical implications. It is characterized by high mortality rates and limited effective therapies. Microsatellite instability (MSI) has been recognized as a subgroup with a good prognosis based on TCGA and ACRG categorizations. Besides its prognostic and predictive value, gastric cancers with high MSI exhibit different clinical behaviors. The prevalence of high MSI has been assessed in gastric cancer worldwide, especially in East Asia, but there is a lack of such information in the Middle East. Therefore, this study aimed to investigate the incidence and status of MSI in Iranian gastric cancer patients using 53 samples collected from 2015 to 2020 at Taleghani Hospital Medical Center. DNA from tumoral and normal tissues were extracted and assessed through multiplex-PCR based on five mononucleotide repeats panel. Clinicopathological variables, including age, sex, Lauren classification, lymph node involvement, TNM stage, differentiation, localization, and tumor size, were also analyzed. With 2 males and 2 females, high microsatellite instability represented a small subgroup of almost 7.5% of the samples with a median age of 60.5 years. High microsatellite instability phenotypes were significantly associated with patients aged 68 years and older (p‑value of 0.0015) and lower lymph node involvement (p‑value of 0.0004). Microsatellite instability was also more frequent in females, with distal gastric location, bigger tumor size, and in the intestinal type of gastric cancer rather than the diffuse type.

Deep sequencing reveals recurrent somatic mutations and distinct molecular subgroups in gastric cancer in Mizo population, North East India

In India, Mizoram has the highest incidence of gastric cancer (GC) which might be associated with environmental factors such as diet, Helicobacter pylori (H.pylori) and Epstein-Barr virus (EBV) infections, and somatic genomic alterations. We performed PCR cum sequencing and fragment analysis for detection of H. pylori/EBV infection and microsatellite Instability (MSI) in GC patients (N = 68). Somatic mutations were identified by targeted and exome sequencing. We found 87% of GC patients infected with H. pylori and or EBV. Pathogenic infections were mostly mutually exclusive with only 16% of coinfection. TP53, MUC6, and ARID1A were significantly mutated. Two molecular subgroups with distinctive mutational profiles were identified: (1) patients harboring mutations in TP53 and (2) patients harboring mutations in RTK/RAS/PI3-K signaling pathway and chromatin-remodeling genes. Therefore, EBV and H. pylori infections and somatic mutations in the genes involved in RTK/RAS/PI3K signaling pathway, chromatin-remodeling, and TP53 might drive GC development and progression in Mizo patients.

Cancer awareness, diagnosis and treatment needs in Mizoram, India: evidence from 18 years trends (2003-2020)

Background

Despite being the second least populated state, Mizoram exhibits the highest incidence rate of cancer in India. Its inhabitants, constituting an endogamous and isolated population, have embraced their own distinct culture, way of life and dietary preferences, setting them apart from the rest of mainland India. In 2003, the Mizoram Population Based Cancer Registry (PBCR) was established under the auspices of the National Centre for Disease Informatics and Research (NCDIR), a division of the Indian Council of Medical Research (ICMR), in collaboration with the Department of Health & Family Welfare of the Government of Mizoram, India.

Methods

Cancer incidence and mortality data were extracted from the Mizoram PBCR spanning the years 2003-2020. The Age Standardized Incidence Rate (ASIR) and Age Standardized Mortality Rate (ASMR) were computed per 100,000 individuals, utilizing Segi's World Standard Population as the benchmark. The trajectory of these changes was analysed employing the Joinpoint Regression Analysis Program, Version 4.9.1.0.13, to unveil the Annual Percent Change (APC) with a 95% Confidence Interval and a Significance test (p < 0.05) using Monte Carlo Permutation. The resulting graphical visualizations were generated using Flourish Studio.15.

Findings

The overall ASIR for all cancer sites among men was 197.2 per 100,000, while for women, it was 164.9 per 100,000. Among men, the most prevalent cancer site was the Stomach (ASIR = 41.4), followed by Head & Neck, Lung, Oesophagus, Colorectal, Liver, Urinary, Non-Hodgkin's Lymphoma and Prostate cancers. Conversely, among women, Lung cancer exhibited the highest incidence (ASIR = 26.7), succeeded by Cervical, Breast, Stomach, Head & Neck, Colorectal, Oesophagus, Liver and Ovarian cancers. Stomach cancer emerged as the leading cause of death among men (ASMR = 22.6) and among women, Lung cancer held the highest ASMR (15.9). Joinpoint regression analysis revealed a rising trend in incidence and mortality over time for overall cancer sites. Among the primary cancer sites contributing to incidence and mortality, an increase in APC was observable for all, except Stomach cancer, in both men and women. The diagnostic approach, except for cases of cancer with unknown primary sites, involved a microscopic method.

Interpretation

This cross-sectional study examines PBCR reports spanning from 2003 to 2020, shedding light on a consistent uptick in cancer incidence and mortality trends in Mizoram. Stomach cancer emerges as the most prevalent and primary cause of cancer-related deaths among men, while Lung cancer takes a parallel role in women. The elevated cancer incidence and the growing trend among younger generations might stem from the static lifestyle and dietary patterns prevalent within the endogamous tribal population, potentially contributing to a genetic predisposition. The escalation in mortality rates could be attributed to a dearth of specialized diagnostic facilities and skilled human resources, treatment strategies guided by genomic research and transportation challenges. This underscores the urgent requirement for comprehensive scientific exploration across diverse facets. The implementation of easily accessible diagnostic facilities in proximity and genetic testing for pharmacogenomics to enhance prognoses would also aid in mitigating the burden and advancing the healthcare system's effectiveness.

Funding

Population Based Cancer Registry (PBCR) was supported by National Centre for Disease Informatics and Research (NCDIR) of the Indian Council of Medical Research (ICMR), India.

Long-term consumption of fermented pork fat-based diets differing in calorie, fat content, and fatty acid levels mediates oxidative stress, inflammation, redox imbalance, germ cell apoptosis, disruption of steroidogenesis, and testicular dysfunction in Wistar rats

There is a dearth of experimental evidence available as to whether the consumption of fermented pork fat (FPF) food has any harmful effects on metabolism and reproduction due to its excessive calories, high fat content, and fatty acid methyl ester (FAME) levels. We hypothesized that exposure to a FPF-diet with excessive calories, a high fat content, and high FAME levels alters testicular physiology and metabolism, leading to permanent damage to the testicular system and its function. Thirteen-week-old male rats (n = 20) were assigned to a high-calorie, high-fat diet (FPF-H, fat-60%, 23 kJ/g), a moderate-calorie, moderate-fat diet (FPF-M, fat-30%, 17.5 kJ/g), a low-calorie and low-fat diet (FPF-L, fat-15%, 14.21 kJ/g) compared to the standard diet (Control, fat-11%, 12.56 kJ/g) orally for 90 days. GC-MS analysis of the three FPF-diets showed high quantities of saturated fatty acids (SFAs) and polyunsaturated fatty acids-ω6 (PUFA-ω6) and low levels of monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids-ω3 (PUFA-ω3) compared to the control diet. Consequently, the levels of serum FAMEs of the FPF-diet fed rats were significantly increased. In addition, a high level of n-6:n-3 PUFA towards PUFA-ω6 was observed in the serum of FPF-diet fed rats due to the high content of linoleic, γ-linolenic, and arachidonic acid. Long-term consumption of FPF-diets disturbed the anthropometrical, nutritional, physiological, and metabolic profiles. Furthermore, administration of FPF-diets generated metabolic syndrome (dyslipidemia, leptinemia, insulin resistance, obesity, hepato-renal disorder and function), increased the cardiovascular risk factors, and triggered serum and testis inflammatory markers (interleukin-1↑, interleukin-6↑, interleukin-10↓, leukotriene B4↑, prostaglandin↑, nitric oxide↑, myeloperoxidase↑, lactate dehydrogenase↑, and tumor necrosis factor-α↑). Activated testis oxidative stress (conjugated dienes↑, lipid hydroperoxides↑, malondialdehyde↑, protein carbonyl↑, and fragmented DNA↑) and depleted antioxidant reserve (catalase↓, superoxide dismutase↓, glutathione S-transferase↓, reduced glutathione↓, glutathione disulfide↑, and GSH:GSSG ratio↓) were observed in FPF-diet fed rats. Disrupted testis histoarchitecture, progressive deterioration of spermatogenesis, poor sperm quality and functional indices, significant alterations in the reproductive hormones (serum and testis testosterone↓, serum estradiol↑, serum luteinizing hormone↓, and follicle-stimulating hormone↑), were noted in rats fed with FPF diets than in the control diet. Severe steroidogenic impairment (steroidogenic acute regulatory protein, StAR↓; 3β-hydroxysteroid dehydrogenase, 3β-HSD↓; and luteinizing hormone receptor, LHR↓), deficiency in germ cells proliferation (proliferating cell nuclear antigen, PCNA↓), and abnormally enhanced testicular germ cell apoptosis (terminal deoxynucleotidyl transferase dUTP nick end labeling, TUNEL assay↑; B-cell lymphoma-2, BCL-2↓; Bcl-2-associated X protein, BAX↑; and BAX/BCL-2 ratio↑) were remarked in the FPF-diet administered rats in comparison with the control diet. In conclusion, the long-term feeding of an FPF-diet with excessive calories, a high fat content, and high FAME levels induced oxidative stress, inflammation, and apoptosis, resulting in metabolic syndrome and hampering male reproductive system and functions. Therefore, the adoption of FPF diets correlates with irreversible changes in testis metabolism, steroidogenesis, germ cell proliferation, and apoptosis, which are related to permanent damage to the testicular system and function later in life.

Co-infection relationship with Epstein-Barr virus in gastroduodenal diseases with Helicobacter Pylori. Quantitative PCR and EBNA-1 gene-based approach

Objective: Helicobacter pylori (Hp) and Epstein-Barr virus (EBV) are involved in gastric cancer (GC) etiology. EBV/Hp co- infection was thought synergistically increase gastroduodenal disease occurence. We aimed to determine the presence of EBV/Hp co-infection in gastroduodenal diseases. Methods: The study group had 68 Hp (+) cases [25 GC, 13 IM (intestinal metaplasia), 30 PU (peptic ulcer)], and the control group had 40 NUD (non-ulcer dyspepsia) cases [20 Hp+, 20 Hp-]. EBV-DNA was detected by non-polymorphic EBNA-1 gene-based qPCR. EBV/EBNA-1 IgG levels were determined by quantitative and qualitative ELISA methods, respectively. Results: EBV-DNA positivity was 32% (8/25), 6.6% (2/30) and 5% (1/20) in GC, PU and NUD Hp (+) cases, respectively. There was a significant difference (p = 0.001) between GC (32%) and NUD Hp (+) (5%) cases in terms of EBV-DNA positivity. Mean EBV-DNA copy numbers were 6568.54 ± 20351, 30.60 ± 159.88 and 13.85 ± 61.93 for GC, PU, and NUD, respectively. In terms of the mean EBV-DNA copy number, a significant difference was found between the groups (p = 0.005). In terms of EBV/EBNA-1 IgG antibody positivity, no significant difference was found between GC and NUD cases (p = 0.248). EBV DNA positivity was found to be significant (odds ration [OR] = 26.71 (p=0.009, %95CI 2.286- 312.041) in multivariate logistic regression. Conclusioin: Although we had a small number of GC cases, it can be suggested that the estimated risk created by the synergistic effect based on the addition of EBV increased 26 times in the presence of Hp in GC.

Geospatial Assessments of DNA Adducts in the Human Stomach: A Model of Field Cancerization

BACKGROUND

Field cancerization is a popular concept regarding where cancer cells arise in a plane, such as the opened-up gastrointestinal mucosa. The geospatial distribution of DNA adducts, some of which are believed to initiate mutation, may be a clue to understanding the landscape of the preferred occurrence of gastric cancer in the human stomach, such that the occurrence is much more frequent in the lesser curvature than in the greater curvature.

METHODS

Seven DNA adducts, C5-methyl-2'-deoxycytidine, 2'-deoxyinosine, C5-hydroxymethyl-2'-deoxycytidine, N6-methyl-2'-deoxyadenosine, 1,N6-etheno-2'-deoxyadenosine, N6-hydroxymethyl-2'-deoxyadenosine, and C8-oxo-2'-deoxyguanosine, from different points and zones of the human stomach were semi quantitatively measured by liquid chromatography/tandem mass spectrometry. The differences in the quantity of these DNA adducts from the lesser and greater curvature, the upper, middle and lower third zones, the anterior and posterior wall of the stomach, and the mucosae distant from and near the tumor were compared to determine whether the location preference of cancer in the stomach could be explained by the distribution of these DNA adducts. Comparisons were conducted considering the tumor locations and operation methods.

CONCLUSIONS

Regarding the DNA adducts investigated, significant differences in quantities and locations in the whole stomach were not noted; thus, these DNA adducts do not explain the preferential occurrence of cancer in particular locations of the human stomach.