Immune modulation by probiotics in deterring carcinogenesis with an emphasis on oral cancer: A narrative review

ABSTRACT Probiotics modulate immune responses, enhance anti-tumoral immune surveillance, promote apoptosis of cancer cells, suppress tumor progression by their cytotoxic activity, and target the epigenetic changes in the cancer cell population. Evidence from the literature suggests that the role of probiotics in oral carcinogenesis is limited as compared to that in colon and gastric cancer. The present review aims to describe the immune modulation by probiotics in deterring carcinogenesis with an emphasis on oral cancer. We searched for relevant articles (in vitro and animal studies) published between January 2011 and December 2022 in PubMed, Scopus, and Google Scholar, both by electronic and manual means with the medical subject headings (MeSH) terms: “probiotics,” “carcinogenesis,” “immune modulation,” and “oral cancer.” The identified studies were analyzed by two independent reviewers according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Eight articles met the requirements and were included. The data suggested that probiotics had immunomodulatory and anti-tumorigenic effects. Clinical studies are required to encourage the assessment of probiotics to inhibit tumor cell proliferation, prevent metastasis, and support anti-cancer therapy.