The functional prediction analysis of oral bacterial communities showed that genes involved in cell adhesion molecules (p<0.001), extracellular matrix molecule-receptor interaction (p<0.001), focal adhesion (p<0.001), and regulation of actin cytoskeleton (p<0.001) were associated with glioma grades, and some microbial gene functions involving lipid metabolism and the adenosine 5'-monophosphate-activated protein kinase signaling pathway were significantly more enriched in IDH1 mutant gliomas than compared with the IDH1-wild-type gliomas. Here, IDH1 is linked to glioma.