The Microbiome in Cancer Therapy Response

Cancer is the second leading cause of death worldwide. Although advances in early diagnosis and therapies have increased survival rates, the disparity in treatment outcomes among patients underscores the existence of unexplored pathways that influence therapeutic responses. Recent studies have highlighted the microbiome's crucial role in cancer risk and progression through mechanisms such as inflammatory and immune modulation, genetic instability, microbial translocation, and the production of metabolites like short-chain fatty acids. Emerging evidence suggests that the microbiome not only impacts cancer development but also affects responsiveness to chemotherapy and immunotherapy, as well as the occurrence of side effects. This relationship is complex and bidirectional; therapeutic drugs can alter the gut microbiota, while specific microbial strains can transform these drugs into different metabolites. Experiments with germ-free or antibiotic-treated mice have demonstrated that the microbiota can enhance the efficacy of various cancer treatments. Additionally, fecal microbiota transplantation has helped identify bacterial strains responsible for treatment outcomes and side effects. While the majority of the human microbiota resides in the gut, other tissues such as the lung, breast, and skin also harbor distinct microbial populations affected by cancer and its treatments. Tumors themselves possess unique microbiomes that modulate and are influenced by therapeutic responses. Differences in microbial signatures between healthy controls and adjacent tumor tissues, as well as correlations between distant metastasis and specific microbial compositions, further emphasize the role of the microbiome in cancer.

This research topic aims to advance the understanding of the interaction between the host microbiome and cancer therapy response, including the occurrence of side effects. We seek to answer specific questions such as how the gut microbiota metabolizes cancer drugs, how it modulates immune responses to therapies, and how its modulation can be integrated into cancer treatments. Hypotheses to be tested include the potential for specific microbial strains to enhance or inhibit therapeutic efficacy and the role of non-cancerous tissue microbiota in cancer development and treatment responses.

To gather further insights into the boundaries of this research, we welcome articles addressing, but not limited to, the following themes:

- Gut microbiota and metabolism of drugs used in the treatment of cancer.
- Gut microbiota and immune modulation in response to cancer therapies.
- Modulation of the gut microbiota as part of cancer treatments, such as the use of prebiotics, probiotics, and fecal microbiota transplantation.
- Non-cancerous tissue microbiota dysbiosis in cancer development and therapeutic responses.
- Tumor microbiota populations and response to therapies.