1309 Differential microbial enrichment is associated with oral cancer and perineural invasion

Background Advanced oral cavity squamous cell carcinoma (OSCC) is an aggressive disease, with 5-year overall survival rates below 50%. 1 While smoking and alcohol are the most established risk factors, there is growing evidence implicating the role of the oral microbiome in promoting immunosuppres-sive states in OSCC. 2-6 The objective of this study was to evaluate the taxonomic profile of oral bacteria in advanced OSCC patients and correlate with clinicopathologic features. approved this study of patients diagnosed with treated from Samples were taken from tumor and paired adjacent normal tissues at the time of surgery and snap frozen. Demographics, clinical and pathologic information was collected. DNA from 51 samples was isolated and 16s rRNA gene sequencing was performed after PCR amplification of the V1-V3 regions of the 16s rRNA gene for paired samples. 16S rRNA sequences were processed using DADA2, implemented in QIIME2 package, and taxonomic assignments were made using RDA classifier using the Human Oral Microbiome Data-base V15.22 as the reference database. Sequencing reads proc-essing, denoising, dereplicating, chimeras filtering, and amplicon sequence variants (ASVs) generation was done using DADA2. The association between clinicopathological factors and bacterial profiles was evaluated using R Software.