Oral hygiene might prevent cancer

Abstract

Many evidences support that species from the Human Oral Microbiome Database such as Fusobacterium nucleatum or Bacteroides, linked previously to periodontitis and appendicitis, play a role in colorectal cancer (CRC), including metastasis. These typically oral species are invasive anaerobes that form biofilms in their virulent state. Aspirin (a NSAID) has been recently included into routine CRC prevention rationale. NSAIDs can prevent the growth of neoplastic lesions by inhibiting COX enzymes and another set of recently identified COX-independent targets, which include the WNT, AMPK and MTOR signaling pathways, the crosstalk between nucleoli and NF-κB transcriptional activity in apoptosis, and the biochemistry of platelets. These are signaling pathways related to tumor-promoting inflammation. In this process, pathogens or simple deregulation of the microbiota play an important role in CRC. Aspirin and other NSAIDs are efficient inhibitors of biofilm formation and able to control periodontitis development preventing inflammation related to the microbiota of the gingival tissue, so its seems plausible to include this pathway in the mechanisms that aspirin uses to prevent CRC. We propose arguments suggesting that current oral hygiene methods and other future developments against periodontitis might prevent CRC and probably other cancers, alone or in combination with other options; and that the multidisciplinary studies needed to prove this hypothesis might be relevant for cancer prevention.

Keywords: Cancer research; Dentistry; Evidence-based medicine; Microbiology.

Fig. 1

The red arrows point to demonstrated events in CRC: the role of biofilms and oral microbioma in inflammation-driven tumorigenesis and the preventive role of aspirin in CRC. The green arrows hypothesize that a) one of the pathways affected by aspirin might be the formation of biofilms in the gut; b) advances in periodontitis prevention, by NSAIDs or dental plaque cleaning might impact in cancer prevention; c) the latter has shown an impact on rheumatoid arthritis. However, only two epidemiological studies so far have suggested this relationship between periodontitis prevention and cancer.