review on relationship between microbiome, cancer cells and immunotherapy in canine

Cancer is a substantial global health problem both in humans and animals with a consistent increase in mortality and incidence rate. the commensal microbiota has been involved in the regulation of several physiological and pathological processes, both within the gastrointestinal system and at distant tissue locations. cancer is not an exception, and different aspects of the microbiome have been described to have anti- or protumour effects. the information in this study was obtained by searching the databases science direct, pubmed, sid, and google scholar using the keywords microbiome , cancer and immunotherapy . the microbiome has clearly been established as a cutting-edge field in tumor immunology and immunotherapy. growing evidence supports the role of the microbiome in immune surveillance, self-tolerance, and response to immune checkpoint inhibitors such as anti pd-l1 and ctla-4 blockade. recent studies including those using fecal microbial transplantation (fmt) have demonstrated that response to checkpoint immunotherapies may be conferred or eliminated through gut microbiome modulation. multiple cancers in dogs, including lymphoma, high grade gliomas, melanomas and osteosarcoma (osa) closely resemble their human analogues, particularly in regard to metastasis, disease recurrence and response to treatment. importantly, dogs with these spontaneous cancers also have intact immune systems, suggesting that microbiome analyses in these subjects may provide high yield information, especially in the setting of novel immunotherapy regimens which are currently expanding rapidly in canine comparative oncology. additionally, as onco-microbiotic therapies are developed to modify gut microbiomes for maximal responsiveness, large animal models with intact immune systems will be useful for trialing interventions and monitoring adverse events. together, pre-clinical mechanistic studies and large animal trials can help fully unlock the potential of the microbiome as a diagnostic and therapeutic target in cancer.