A Review of Gastric Cancer Research in Malaysia

Pan-Asian adapted ESMO Clinical Practice Guidelines for the diagnosis, treatment and follow-up of patients with gastric cancer

The European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of patients with gastric cancer (GC), published in late 2022 and the updated ESMO Gastric Cancer Living Guideline published in July 2023, were adapted in August 2023, according to previously established standard methodology, to produce the Pan-Asian adapted (PAGA) ESMO consensus guidelines for the management of Asian patients with GC. The adapted guidelines presented in this manuscript represent the consensus opinions reached by a panel of Asian experts in the treatment of patients with GC representing the oncological societies of China (CSCO), Indonesia (ISHMO), India (ISMPO), Japan (JSMO), Korea (KSMO), Malaysia (MOS), the Philippines (PSMO), Singapore (SSO), Taiwan (TOS) and Thailand (TSCO), coordinated by ESMO and the Japanese Society of Medical Oncology (JSMO). The voting was based on scientific evidence and was independent of the current treatment practices, drug access restrictions and reimbursement decisions in the different Asian regions represented by the 10 oncological societies. The latter are discussed separately in the manuscript. The aim is to provide guidance for the optimisation and harmonisation of the management of patients with GC across the different regions of Asia, drawing on the evidence provided by both Western and Asian trials, whilst respecting the differences in screening practices, molecular profiling and age and stage at presentation. Attention is drawn to the disparity in the drug approvals and reimbursement strategies, between the different regions of Asia.

Updated Epidemiology of Gastric Cancer in Asia: Decreased Incidence but Still a Big Challenge

Despite the decline in incidence and mortality rates, gastric cancer (GC) is the fifth leading cause of cancer deaths worldwide. The incidence and mortality of GC are exceptionally high in Asia due to high H. pylori infection, dietary habits, smoking behaviors, and heavy alcohol consumption. In Asia, males are more susceptible to developing GC than females. Variations in H. pylori strains and prevalence rates may contribute to the differences in incidence and mortality rates across Asian countries. Large-scale H. pylori eradication was one of the effective ways to reduce GC incidences. Treatment methods and clinical trials have evolved, but the 5-year survival rate of advanced GC is still low. Efforts should be put towards large-scale screening and early diagnosis, precision medicine, and deep mechanism studies on the interplay of GC cells and microenvironments for dealing with peritoneal metastasis and prolonging patients' survival.

m6A Methyltransferase 3 Promotes the Proliferation and Migration of Gastric Cancer Cells through the m6A Modification of YAP1

Gastric cancer is the most common gastrointestinal tumor with an increasing incidence. Furthermore, advanced gastric cancer is more common, but the mechanism underlying the proliferation and metastasis of gastric cancer has not been thoroughly explored. N6-methyladenosine (m6A) methyltransferase 3 (METTL3) may be involved in the proliferation and metastasis of gastric cancer. Therefore, Yes-associated protein 1 (YAP1) in the Hippo pathway was selected as the target, and the relationship between METTL3 and the proliferation and metastasis of gastric cancer was proved through a series of experiments. This research showed that the expression of m6A and METTL3 was upregulated in human gastric cancer tissues and gastric cancer cell lines. After lentiviral transfection, METTL3 silencing in AGS (human gastric adenocarcinoma cell line AGS) and MKN-45 (human gastric cancer cell line MKN-45) gastric cancer cell lines directly inhibited the proliferation, aggressiveness, and migration of gastric cancer cells. Mechanically, the inhibition of the YAP1-TEAD signaling pathway by peptide 17 reduces m6A methylation and the total mRNA level of YAP1. It also eliminates the promoting effect of METTL3 on the proliferation and migration of gastric cancer cells. In turn, the overexpression of YAP1 eliminates the inhibitory effect of METTL3 silencing on the proliferation, migration, and invasion of gastric cancer cells. This article proved that m6A methyltransferase METTL3 promoted the proliferation and migration of gastric cancer cells through the m6A modification of YAP1.

Screening, Monitoring, and Treatment of Precancerous Atrophic Gastritis in the Prospective Study for Seven Years

AIM

Develop a program to identify, treat, and prevent severe atrophic gastritis to reduce gastric cancer incidence and mortality.

MATERIALS AND METHODS

In total, 2,847 people aged > 40 years old underwent serological noninvasive screening for atrophic gastritis by identifying postprandial gastrin-17 and pepsinogen-1 in the fasting state. Anti-H pylori IgG was found in 2,134 patients. Seven years later, 2,220 patientswho had undergone serological noninvasive screening were asked to fill out a questionnaire survey (were interviewed). We could not find any information on 627 of 2,847 patients. Next, 75 patients with multifocal atrophic gastritis who underwent gastroscopy and biopsies (the Updated Sydney System (USS)) were selected. To study gastrin-17 production, morpho-functional correlation was studies in 75 patients with multifocal atrophic gastritis.

RESULTS

During seven years, no reported case of gastric cancer was done among 2,220 persons who underwent serological screening and treatment. In the same population, 4.3 persons who did not receive screening during the same period, developed gastric cancer and died of it. In this study, we can say that 4.3 lives were saved out of 2,220 tested persons. The cost for screening this number of people amounted to €23,750. A comparison of the prevalence rate of the four stages of multifocal atrophic gastritis based on the data of the histopathology tests and noninvasive serologic screening in accordance with OLGA classification showed a strong correlation (the correlation coefficient is 0.812). This finding suggested that using this classification not only for histopathology tests for atrophic gastritis but also for serologic markers of antral mucosa and corpus ventriculi atrophy: gastrin-17 and pepsinogen-1.

CONCLUSION

Complex pathogenetic treatment of atrophic gastritis significantly reduced gastric cancer risk and incidence for such patients.
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