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A new study by Weiwei Heng and colleagues from the Medical School of Nanjing University in China, published in Microbiology Spectrum, explores the role of oral dysbiosis in the development of oral squamous cell carcinoma (OSCC). Until now, the attention has been primarily focused on bacterial microbiota, while the contribution of the fungal component has been largely ignored. In this study, both the oral bacteriome and mycobiome were analyzed throughout the carcinogenesis process to identify specific alterations and correlations.
OSCC is the most common form of head and neck tumor, yet its etiology remains partially unclear. Early diagnosis is crucial, and the oral mucosa, which is not only a physical barrier against pathogenic invasion but also involved in the development of OSCC, is colonized by a microbiome. Bacteria are the main population, but fungi are also present, and the contribution of the fungal component to our health and its potential interaction with the bacterial sphere is largely unknown.
In this study, the researchers wanted to delve into the fungal side of OSCC development, linking it to the bacterial component, to identify specific alterations during the various stages of the disease. 87 subjects with OSCC, 90 with pre-malignant lesions (OPL), and 90 healthy controls (HC) were studied. The researchers collected and compared oral samples (mucosa, gingival plaque, and saliva) and found the following results:
The OSCC group showed a completely different bacterial profile compared to the other two groups, which were similar to each other regardless of the sampling site. In terms of bacterial richness, OSCC and OPL had significantly lower levels compared to the controls in mucosa and saliva samples. The richness was minimal in the gingival plaque samples of the OPL group. The gingival plaque and mucosa of the OSCC group showed a higher diversity compared to OPL and controls, while saliva showed decreased diversity.
Significant differences were also observed in the fungal profile of mucosa and plaque in the OSCC group, with similar profiles to the healthy controls in saliva samples for both OPL and controls. The fungal richness of the mucosa in the OPL group was significantly higher than the healthy controls, while the plaque of the OSCC group showed a higher richness. Both the OPL and control groups showed a higher richness in the saliva.
The results suggest that the progression of OSCC is related to species differences and functional alterations, especially at the mucosal level, suggesting a spatial contribution of dysbiosis. During the progression of oral squamous cell carcinoma, dysbiosis appears to affect the mucosal part more, with alterations in both bacterial and fungal species and functionality. The study provides valuable insight into the fungal component of oral carcinogenesis and highlights the importance of considering both bacterial and fungal components in future studies of oral dysbiosis.
For more info: journals.asm.org