CTNI-23. DIFFERENT GUT MICROBIOTA COMPOSITION IS ASSOCIATED WITH CHEMOTHERAPY EFFICACY IN PATIENTS WITH DIFFERENT TYPES OF CENTRAL NERVOUS SYSTEM CANCER

Abstract BACKGROUND The relationship between central nervous system cancers and the gut microbiota (GM) is not well understood. The purpose of this study is to retrospective analyze the differences between the composition of the gut microbiota in patients with different neurologic tumors and their correlation with chemotherapy efficacy. METHODS A total of 44 patients participated in the study and were divided into four groups: gliocytoma (GA), medulloblastoma (MB), germ cell tumors (GT), and diffuse large B-cell lymphoma (DB) based on their pathological diagnosis. Fecal samples were collected from patients for 16S amplicon sequencing to analyze GM composition. Moreover, all the patients were classified into completed response (CR), stable disease (SD), and progressive disease (PD) groups based on the clinical outcomes of chemotherapy. PLS-DA analysis and heatmap analysis were used to reveal the correlation between GM composition and outcomes of chemotherapy. RESULTS Phyla taxa comparison showed the detailed GM composition among these four groups. The phylum of Bacteroidetes was higher in GA group when compared to the other groups. And the phylum of Fusobacteria could only be found in GA and MB groups while the phylum of Verrucomicrobia showed a significant accumulation in DB group. the genera of Ruminococcus, Gemmiger, and Parasutterella were accumulated in the patients with the completed response of chemotherapy. Besides, patients in SD group had higher abundance of the genera of Prevotella, Tyzzerella, and Odoribacter. While patients in PD group showed the higher abundance of Streptcoccus, Fusobacterium, Lachnospira, and Holemanella. CONCLUSION We firstly drew the GM composition profile of the patients with GA, MB, GT, and DB to show the different GM composition of the diseases. Moreover, the gut microbiota composition correlates with chemotherapy outcomes in central nervous system cancer patients so may serve as a potential biomarker for predicting chemotherapy efficacy.