Stomach cancer is a global health challenge due to its increasing prevalence. The intestinal microbiota of humans plays a vital role in producing short-chain fatty acids, developing resistance towards pathogenic microbes, nutrient absorption, modulation in immunological response, metabolism, synthesis of vitamins, and gut immune system development. Many diseases or disorders, including cancers, obesity, psychiatric illnesses, rheumatoid arthritis, and inflammatory bowel syndrome, are associated with an imbalance of microbiotas. Earlier reports suggest that probiotics via the oral route act as a functional food and suppress cancer development. Further, some probiotics are clinically effective in reducing post-operative inflammation in cancer patients. Probiotics primarily display inhibitory effects against H. pylori infections in the digestive tract. The combination of probiotics with antibiotics has effectively eradicated H. pylori infections. Besides, probiotics reduce the pro-carcinogens metabolism, they also diminish the growth of pathogens and improve the consistency of the intestinal barrier. Moreover, compounds produced by the microorganisms are reported to interact unswervingly with cancer cells and affect their survival. The therapeutic efficacy and adverse side-effects of the strategies used for stomach cancer prevention could be improved by using probiotics either as adjuvant or neo-adjuvant as the safety concern of the commercially used strains has been verified. The underlying mechanism describing microbiota's effect on oncogenic activation, carcinogenic metabolite production, DNA damage, inhibition of tumour immunity, and chronic inflammation induction still needs a more detailed investigation. In addition, doubleblind, placebo-controlled, randomized, and well-designed clinical studies are required to understand the efficacy and mode of action to reduce the death rate and stomach cancer burden. In depth studies are essential to set probiotics as an eccentric strategy for stomach cancer prevention and treatment.
Keywords: Gut immune system, H. pylori, Immune system, Inflammation, Intestinal microbiota, Probiotics, Stomach cancer, Tumour immunity.
