Oral microbiota and vitamin D impact on oropharyngeal squamous cell carcinogenesis: a narrative literature review

Abstract

An emerging body of research is revealing the microbiota pivotal involvement in determining the health or disease state of several human niches, and that of vitamin D also in extra-skeletal regions. Nevertheless, much of the oral microbiota and vitamin D reciprocal impact in oropharyngeal squamous cell carcinogenesis (OPSCC) is still mostly unknown. On this premise, starting from an in-depth scientific bibliographic analysis, this narrative literature review aims to show a detailed view of the state of the art on their contribution in the pathogenesis of this cancer type. Significant differences in the oral microbiota species quantity and quality have been detected in OPSCC-affected patients; in particular, mainly high-risk human papillomaviruses (HR-HPVs), Fusobacterium nucleatum, Porphyromonas gingivalis, Pseudomonas aeruginosa, and Candida spp. seem to be highly represented. Vitamin D prevents and fights infections promoted by the above identified pathogens, thus confirming its homeostatic function on the microbiota balance. However, its antimicrobial and antitumoral actions, well-described for the gut, have not been fully documented for the oropharynx yet. Deeper investigations of the mechanisms that link vitamin D levels, oral microbial diversity and inflammatory processes will lead to a better definition of OPSCC risk factors for the optimization of specific prevention and treatment strategies.

Keywords:

• Bacterial
• fungal and epitheliotropic viral oral pathogens
• oral microbiota
• oropharyngeal squamous cell carcinoma
• vitamin D
• health

Acknowledgement

The authors warmly thank Dr. Nina Vinot for the scientific linguistic revision.

Author contributions

Paola Zanetta contributed to bibliographic resources research and selection, figures preparation, data curation, and writing. Diletta Francesca Squarzanti contributed to bibliographic resources research and selection, review writing, editing and submission. Rita Sorrentino contributed to bibliographic resources research methodology/interpretation/selection and writing. Roberta Rolla contributed to bibliographic resources research, substantial contribution to the review design and writing; funding acquisition. Paolo Aluffi Valletti contributed to supervision, review draft and revision, funding acquisition. Massimiliano Garzaro contributed to bibliographic resources research, contribution to the review design and writing; funding acquisition. Valeria Dell’Era contributed to bibliographic resources research and selection. Angela Amoruso contributed to supervision of the review article. Barbara Azzimonti contributed to supervision, concept, design and writing of the review article; bibliographic resources research, funding acquisition’s PI, project administration. All the authors approved their reciprocal contribution respect to the final submitted version of the manuscript. They are all accountable for their own contributions and ensure the accuracy of any part of the work.

Disclosure statement

The authors declare no conflict of interest. The sponsors had no role in the design, execution, interpretation or writing of the study.

Additional information

Funding

PZ, RR, PAV, MG, and BA have been partially supported by the “FAR-2017” funding provided by UPO. PZ has also partially been supported by FastMed Italia Srl. DFS has partially been supported by Probiotical Research SpA.