Dysbiosis of salivary microbiome and cytokines influence oral squamous cell carcinoma through inflammation

Advanced combinatorial treatments of surgery, chemotherapy, and radiotherapy do not have any effect on the enhancement of a 5-year survival rate of oral squamous cell carcinoma (OSCC). The discovery of early diagnostic non-invasive biomarkers is required to improve the survival rate of OSCC patients. Recently, it has been reported that oral microbiome has a significant contribution to the development of OSCC. Oral microbiome induces inflammatory response through the production of cytokines and chemokines that enhances tumor cell proliferation and survival. The study aims to develop saliva-based oral microbiome and cytokine biomarker panel that screen OSCC patients based on the level of the microbiome and cytokine differences. We compared the oral microbiome signatures and cytokine level in the saliva of OSCC patients and healthy individuals by 16S rRNA gene sequencing targeting the V3/V4 region using the MiSeq platform and cytokine assay, respectively. The higher abundance of Prevotella melaninogenica, Fusobacterium sp., Veillonella parvula, Porphyromonas endodontalis, Prevotella pallens, Dialister, Streptococcus anginosus, Prevotella nigrescens, Campylobacter ureolyticus, Prevotella nanceiensis, Peptostreptococcus anaerobius and significant elevation of IL-8, IL-6, TNF-α, GM-CSF, and IFN-γ in the saliva of patients having OSCC. Oncobacteria such as S. anginosus, V. parvula, P. endodontalis, and P. anaerobius may contribute to the development of OSCC by increasing inflammation via increased expression of inflammatory cytokines such as IL-6, IL-8, TNF-α, IFN-γ, and GM-CSF. These oncobacteria and cytokines panels could potentially be used as a non-invasive biomarker in clinical practice for more efficient screening and early detection of OSCC patients.