Oral microorganisms cause cancer

  A study by Yvonne Kapila of the University of California, San Francisco and others published in the journal PLOS Pathogen on October 1 showed that pathogens found in the tissues surrounding teeth can lead to the occurrence of highly aggressive oral cancer. In addition, studies have shown that the formation of oral cancer mediated by pathogens is inhibited by bacterial metabolites (antibacterial peptides and probiotic peptides produced by bacteria).

  Head and neck squamous cell carcinoma (HNSCC) is one of the most common cancers in the world. Oral squamous cell carcinoma (OSCC) is a subtype of HNSCC, accounting for 90% of all oral malignancies, and its five-year survival rate is very low. Risk factors such as smoking, drinking, and human papillomavirus infection are insufficient to explain the incidence and aggressiveness of OSCC. Other factors (such as oral pathogens) may play an important role in the occurrence, development and metastasis of OSCC tumors, but this has not been studied in depth. In this regard, the authors tested whether OSCC is affected by periodontal pathogens.

  They found that three types of periodontal pathogens (Porphyromonas gingivalis, Treponema dentata, and Clostridium sclerotium) enhanced the migration, invasion and tumor formation of OSCC cells in the mouse model. These effects are mediated through the interaction between two signaling pathways: Integrin/FAK and TLR/MyDD88. Lactobacillus (a bacterial metabolite, a commonly used food preservative) can inhibit this process mediated by pathogens. The author said that this study provides the first direct evidence that bacterial metabolites can inhibit the formation of oral cancer mediated by periodontal pathogens. In addition, research results show that nisin has broad therapeutic potential as an antibacterial and anticancer agent, and as an inhibitor of pathogen-mediated cancer formation.

  The author concluded: “Because the probiotic nisin can inhibit pathogen-mediated carcinogenesis, these findings can promote the treatment of oral cancer and establish a new type of cancer treatment based on antibacterial drugs.”