Nature Cancer：肿瘤内细菌抑制具有免疫抑制作用，促进癌症免疫疗法耐药

Core Viewpoint - Immune checkpoint blockade (ICB) therapy has shown promise in improving clinical outcomes for some head and neck squamous cell carcinoma (HNSCC) patients, but the mechanisms regulating treatment response remain poorly understood [3][6]. Group 1: Role of Gut Microbiome - Increasing research emphasizes the significant role of the gut microbiome in determining the effectiveness of immunotherapy, with specific gut bacteria shown to enhance anti-tumor immunity and T cell proliferation in cancer patients [3]. - Intratumoral bacteria have been identified as immunosuppressive and promote resistance to ICB therapy in HNSCC [4]. Group 2: Research Findings - A study analyzing samples from the CIAO clinical trial found that only the total abundance of intratumoral bacteria could predict patient response to ICB therapy, a conclusion validated across multiple independent cohorts [6]. - High abundance of intratumoral bacteria correlates with an immunosuppressive tumor microenvironment characterized by neutrophil accumulation and reduced T cells and other adaptive immune cells [6]. - Experimental manipulation of intratumoral bacterial abundance in a mouse model of HNSCC replicated the immunological associations observed in clinical trial participants [6]. Group 3: Implications for Immunotherapy - The findings indicate that high levels of intratumoral bacteria are a key inhibitory factor for anti-tumor immunity and contribute to resistance against immunotherapy [7].