Core Viewpoint - The study highlights the impact of gut microbiota dysbiosis induced by brain tumors on the efficacy of immunotherapy, suggesting that dietary supplementation with tryptophan can restore gut microbiota and significantly enhance the immune response through T cell circulation [2][11][14]. Group 1: Research Background - The influence of gut microbiota on various tumors, particularly gastrointestinal tumors, is recognized, but its effects on brain tumors remain largely unexplored [2][6]. - Glioblastoma (GBM) is known for its poor prognosis and limited survival rate improvements despite various treatments, attributed to unique characteristics of the tumor microenvironment [4][5]. Group 2: Research Findings - The research utilized a GBM mouse model and employed 16S rRNA sequencing to analyze changes in gut microbiota during tumor progression, finding that tryptophan supplementation could reverse these changes [9]. - Tryptophan supplementation not only restored gut microbiota balance but also significantly improved survival rates in mouse models and enhanced the effectiveness of immunotherapy [9][13]. Group 3: Key Microbial Insights - Among the gut bacteria responding positively to tryptophan, Duncaniella dubosii emerged as a key contributor to the immune modulation effects of tryptophan [10][13]. - The study emphasizes the potential of targeting gut microbiota modulation to improve cancer immunotherapy outcomes, particularly through mechanisms involving T cell regulation [14].