Distribution of relative abundance of genera at (a) Non-tumor and tumor sites of each OSCC subject; and (b) Cumulative non-tumor and tumor libraries, as detected by HOMD and RDP; (c) Pie-chart shows the relative prevalence of gram-negative and gram-positive bacteria and venn diagram depicts the genera in tissue samples of OSCC subjects. *p < 0.1. N–Non-tumor; T–Tumor. Pie-chart shows the relative shift of gram-negative and gram-positive microbiota in non-tumor and tumor tissue samples. Values in the venn diagram represent the genera shared by and exclusive to non-tumor and tumor tissue libraries.