The natural mammalian polyamines putrescine, spermidine and spermine are essential for both normal and neoplastic cell function and replication. Dysregulation of metabolism of polyamines and their requirements is common in many cancers. Both clinical and experimental depletion of polyamines have demonstrated their metabolism to be a rational target for therapy; however, the mechanisms through which polyamines can establish a tumour-permissive microenvironment are only now emerging. Recent data indicate that polyamines can play a major role in regulating the antitumour immune response, thus likely contributing to the existence of immunologically ‘cold’ tumours that do not respond to immune checkpoint blockade. Additionally, the interplay between the microbiota and associated tissues creates a tumour microenvironment in which polyamine metabolism, content and function can all be dramatically altered on the basis of microbiota composition, dietary polyamine availability and tissue response to its surrounding microenvironment. The goal of this Perspective is to introduce the reader to the many ways in which polyamines, polyamine metabolism, the microbiota and the diet interconnect to establish a tumour microenvironment that facilitates the initiation and progression of cancer. It also details ways in which polyamine metabolism and function can be successfully targeted for therapeutic benefit, including specifically enhancing the antitumour immune response.

天然哺乳动物多胺腐胺、亚精胺和精胺对于正常和肿瘤细胞的功能和复制至关重要。多胺及其需求的代谢失调在许多癌症中很常见。多胺的临床和实验消耗均已证明其代谢是治疗的合理目标；然而，多胺建立肿瘤生长微环境的机制现在才刚刚出现。最近的数据表明，多胺在调节抗肿瘤免疫反应中发挥着重要作用，因此可能导致对免疫检查点阻断没有反应的免疫“冷”肿瘤的存在。此外，微生物群和相关组织之间的相互作用创造了一个肿瘤微环境，其中多胺代谢、含量和功能都可以根据微生物群组成、膳食多胺可用性和组织对其周围微环境的反应而发生显着改变。本视角的目标是向读者介绍多胺、多胺代谢、微生物群和饮食相互关联以建立促进癌症发生和进展的肿瘤微环境的多种方式。它还详细介绍了如何成功靶向多胺代谢和功能以获得治疗益处，包括特异性增强抗肿瘤免疫反应。