Oral Dysbiosis in Oral Squamous Cell Carcinoma (OSCC).
Background: Oral dysbiosis plays an important role in pathogenesis of oral squamous cell carcinoma (OSCC). Our study aimed to perform pairwise comparison of oral microbiota, especially the bacteriome, of OSCC tumoral surface vs healthy oral mucosa and supragingival dental plaque samples and evaluate the association of a novel bacteriome-based Oral Dysbiosis Index (bbODI) with the OSCC surface.  Methods: This pilot observational study used in total 84 patient-matched samples from 21 patients with OSCC. Samples were taken from OSCC tumoral surface (swabs and biopsies), healthy oral mucosa (tongue and buccal swabs), and supragingival dental plaque swabs. Bacteriomes from all types of swabs were analyzed by 16S rRNA amplicon sequencing. The presence of microscopic fungi was evaluated in buccal swabs using conventional culture techniques, and immunohistochemical analysis of selected viruses was performed in paraffin-embedded tumor tissues.  Results: The bacteriome a-diversity indices were similar among all studied matrices. The relative abundance of genus Fusobacterium, ratio of relative abundances of gram-negative to gram-positive bacterial genera, and the bbODI significantly differed on the tumor surface vs patient-matched healthy oral mucosa (both buccal and tongue swabs) and supragingival dental plaque samples. Oral candidosis was found in 25 % of patients; all patients were negative for cytomegalovirus and Epstein-Barr virus.  Conclusions: Our study showed that certain characteristics of bacteriome composition of the OSCC surface differ from patient-matched samples of healthy oral mucosa and supragingival dental plaque. The proposed bbODI appears to be a promising non-invasive tool for identification of bacteriome disruption on OSCC surface.    <br>    <br>                                                                                                                                                                                                                                                                                                                 Funding:<br> The work was supported by Programme JAC – project SALVAGE (CZ.02.01.01/00/22_008/0004644) financed by the Ministry of Education, Youth and Sports – co-funded by the European Union. The study was supported by the Ministry of Health of the Czech Republic, grant No. NU20-08-00205 and by a project funded by the University Hospital Brno – RVO (FNBr, 65269705). This publication was supported by the European Union's Horizon 2020 Research and Innovation Programme under grant agreement No. 857560. This publication reflects only the author's view and the European Commission is not responsible for any use that may be made of the information it contains. The authors also thank the Research Infrastructure RECETOX RI (No. LM2023069, funded by MEYS CR) for its supportive background. Computational resources were provided by the e-INFRA CZ project (ID: 90254), which is supported by the Ministry of Education, Youth and Sports of the Czech Republic. We acknowledge the CF Genomics and the CF Bioinformatics supported by the NCMG research infrastructure (LM2023067 funded by MEYS CR), for their support with obtaining the scientific data presented in this paper.  <br> Data were used for published article https://doi.org/10.1080/20002297.2026.2668149.
Background: Oral dysbiosis plays an important role in pathogenesis of oral squamous cell carcinoma (OSCC). Our study aimed to perform pairwise comparison of oral microbiota, especially the bacteriome, of OSCC tumoral surface vs healthy oral mucosa and supragingival dental plaque samples and evaluate the association of a novel bacteriome-based Oral Dysbiosis Index (bbODI) with the OSCC surface.  Methods: This pilot observational study used in total 84 patient-matched samples from 21 patients with OSCC. Samples were taken from OSCC tumoral surface (swabs and biopsies), healthy oral mucosa (tongue and buccal swabs), and supragingival dental plaque swabs. Bacteriomes from all types of swabs were analyzed by 16S rRNA amplicon sequencing. The presence of microscopic fungi was evaluated in buccal swabs using conventional culture techniques, and immunohistochemical analysis of selected viruses was performed in paraffin-embedded tumor tissues.  Results: The bacteriome a-diversity indices were similar among all studied matrices. The relative abundance of genus Fusobacterium, ratio of relative abundances of gram-negative to gram-positive bacterial genera, and the bbODI significantly differed on the tumor surface vs patient-matched healthy oral mucosa (both buccal and tongue swabs) and supragingival dental plaque samples. Oral candidosis was found in 25 % of patients; all patients were negative for cytomegalovirus and Epstein-Barr virus.  Conclusions: Our study showed that certain characteristics of bacteriome composition of the OSCC surface differ from patient-matched samples of healthy oral mucosa and supragingival dental plaque. The proposed bbODI appears to be a promising non-invasive tool for identification of bacteriome disruption on OSCC surface.    <br>    <br>                                                                                                                                                                                                                                                                                                                 Funding:<br> The work was supported by Programme JAC – project SALVAGE (CZ.02.01.01/00/22_008/0004644) financed by the Ministry of Education, Youth and Sports – co-funded by the European Union. The study was supported by the Ministry of Health of the Czech Republic, grant No. NU20-08-00205 and by a project funded by the University Hospital Brno – RVO (FNBr, 65269705). This publication was supported by the European Union's Horizon 2020 Research and Innovation Programme under grant agreement No. 857560. This publication reflects only the author's view and the European Commission is not responsible for any use that may be made of the information it contains. The authors also thank the Research Infrastructure RECETOX RI (No. LM2023069, funded by MEYS CR) for its supportive background. Computational resources were provided by the e-INFRA CZ project (ID: 90254), which is supported by the Ministry of Education, Youth and Sports of the Czech Republic. We acknowledge the CF Genomics and the CF Bioinformatics supported by the NCMG research infrastructure (LM2023067 funded by MEYS CR), for their support with obtaining the scientific data presented in this paper.  <br> Data were used for published article https://doi.org/10.1080/20002297.2026.2668149.