Microbial populations in the oral cavity have been linked with some malignant diseases, however, the evidence in this regard is poor. Oral microorganisms increase cytokine production and other mediators may be related to carcinogenesis. However, the role of the oral microbiome and its taxonomic composition in pediatric cancer has not been studied. We report a pilot study to assess to compare the microbial diversity of saliva in pediatric patients with cancer and without cancer. Materials and methods: Total saliva samples were collected from 3 cases and 3 controls with cancer, with prior informed consent and assent. Metagenomic sequencing was performed and data was analyzed using CosmosID bioinformatics software. Results: the mean age for the cases is 8.67 years and for the 8-year-old controls, the percentage by sex was 33.3% male and 66.6% female. In the shared analysis of bacterial diversity we found a total of 93 genera, the three genera with the highest abundance in the cases were: Prevotella, Streptococcus and Morococcus. A total of 153 species with differential abundance were identified, in the cases the species with the highest abundance were: Neisseria mucosa, Vellodela dispar, Prevotella melaninogenica and Morococcus cerebrosus. We found differences in bacterial diversity and abundance between cases and controls. The main species that we found in greater abundance in the cases have been related to various processes in the oral cavity, Streptococcus sp increases child caries, Prevotella melaninogenica a broad profile of resistance to families of antibiotics, and Morococcus cerebrosus has been associated with the mineralization of the supragingival dental plaque. Finally Vellodela dispar has been associated with bacteremia in cancer patients. In this pilot study a small number of samples were analyzed, the differences in bacterial diversity should be confirmed by conducting studies with a larger number of samples.

Citation Format: Alejandra Beatriz Cervantes Garduño, Milca de la O García, Jesús Adolfo Yamamoto Nagano, Rocio Del Socorro Cardenas Cardos, Liliana Velasco Hidalgo, Blanca Olivia Almazán García, Gabriela Elisa Mercado Celis. Pilot characterization of the salivary microbiome in pediatric cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2368.