Microbial roles in cancer formation, diagnosis, prognosis, and treatment have been disputed for centuries. Recent studies have provocatively claimed that bacteria, viruses, and/or fungi are pervasive among cancers, key actors in cancer immunotherapy, and engineerable to treat metastases. Despite these findings, the number of microbes known to directly cause carcinogenesis remains small. Critically evaluating and building frameworks for such evidence in light of modern cancer biology is an important task. In this Review, we delineate between causal and complicit roles of microbes in cancer and trace common themes of their influence through the host’s immune system, herein defined as the immuno-oncology-microbiome axis. We further review evidence for intratumoral microbes and approaches that manipulate the host’s gut or tumor microbiome while projecting the next phase of experimental discovery.

几个世纪以来，微生物在癌症形成、诊断、预后和治疗中的作用一直存在争议。最近的研究令人兴奋地声称，细菌、病毒和/或真菌在癌症中普遍存在，是癌症免疫治疗的关键因素，并且可以通过工程改造来治疗转移。尽管有这些发现，已知直接导致致癌的微生物数量仍然很少。根据现代癌症生物学，批判性地评估和构建此类证据的框架是一项重要任务。在这篇综述中，我们描述了微生物在癌症中的因果作用和共谋作用，并追踪了它们通过宿主免疫系统（本文定义为免疫肿瘤学微生物组轴）影响的共同主题。我们进一步审查肿瘤内微生物的证据以及操纵宿主肠道或肿瘤微生物组的方法，同时预测下一阶段的实验发现。