Characterization of Oral Cavity Microbiome in Patients with OCSCC

Purpose/Objective(s) Known risk factors for head and neck squamous cell carcinoma (HNSCC) include history of tobacco and/or alcohol use, and persistent HPV infection. Some individuals develop HNSCC without any known risk factors, suggestive of another source contributing to these malignancies. One hypothesis involves the microbiome of these patients, which may contribute to the development and progression OCSCC through metabolic, inflammatory, and/or immune-modulating effects. The oral cavity has a unique microbiota made up of approximately 700+ known microbial species. Studies have shown an association between poor oral hygiene and tooth loss with cancer, implicating the oral microbiome in the development of tumors. Our aim is to characterize and investigate the role of the microbiome in oral cavity squamous cell carcinoma (OCSCC). We swabbed different areas of the oral cavity in patients with OCSCC, pre-malignant lesions, and healthy controls. Materials/Methods From 2020 to 2023, we swabbed the buccal mucosa, tongue and tumor of patients with OCSCC and controls. Samples were analyzed using 16S ribosomal RNA gene sequencing. Alpha and beta diversity were calculated using Faith's phylogenetic index and compared between cohort using a two-sided t-test. Results 91 patients (45 patients with OCSCC, 13 with pre-malignant lesions, 33 controls) were included in our analysis. Patients with OCSCC had significant differences in alpha diversity compared to controls (p=0.018). There was no significant difference in alpha diversity between controls and pre-malignant lesions. Patients with OCSCC had slight differences in beta diversity compared to controls, approaching significance (p=0.030) and no significant difference compared to pre-malignant lesions (p=0.498). Patients with OCSCC were more likely to harbor Neisseriacea species compared to pre-malignant patients and controls. Conclusion This is the first study to date to compare the oral cavity microbiome in patients with OCSCC, pre-malignant lesions, and controls. Here, we show there are significant differences in alpha diversity in patients with OCSCC compared to patients with pre-malignant lesions and controls, meaning patients with OCSCC are more likely to have less diversity of their oral cavity microbiome compared to patients with pre-malignant lesions and controls, implicating microbial dysbiosis as a potential driver of tumor growth/progression. Known risk factors for head and neck squamous cell carcinoma (HNSCC) include history of tobacco and/or alcohol use, and persistent HPV infection. Some individuals develop HNSCC without any known risk factors, suggestive of another source contributing to these malignancies. One hypothesis involves the microbiome of these patients, which may contribute to the development and progression OCSCC through metabolic, inflammatory, and/or immune-modulating effects. The oral cavity has a unique microbiota made up of approximately 700+ known microbial species. Studies have shown an association between poor oral hygiene and tooth loss with cancer, implicating the oral microbiome in the development of tumors. Our aim is to characterize and investigate the role of the microbiome in oral cavity squamous cell carcinoma (OCSCC). We swabbed different areas of the oral cavity in patients with OCSCC, pre-malignant lesions, and healthy controls. From 2020 to 2023, we swabbed the buccal mucosa, tongue and tumor of patients with OCSCC and controls. Samples were analyzed using 16S ribosomal RNA gene sequencing. Alpha and beta diversity were calculated using Faith's phylogenetic index and compared between cohort using a two-sided t-test. 91 patients (45 patients with OCSCC, 13 with pre-malignant lesions, 33 controls) were included in our analysis. Patients with OCSCC had significant differences in alpha diversity compared to controls (p=0.018). There was no significant difference in alpha diversity between controls and pre-malignant lesions. Patients with OCSCC had slight differences in beta diversity compared to controls, approaching significance (p=0.030) and no significant difference compared to pre-malignant lesions (p=0.498). Patients with OCSCC were more likely to harbor Neisseriacea species compared to pre-malignant patients and controls. This is the first study to date to compare the oral cavity microbiome in patients with OCSCC, pre-malignant lesions, and controls. Here, we show there are significant differences in alpha diversity in patients with OCSCC compared to patients with pre-malignant lesions and controls, meaning patients with OCSCC are more likely to have less diversity of their oral cavity microbiome compared to patients with pre-malignant lesions and controls, implicating microbial dysbiosis as a potential driver of tumor growth/progression.