Metformin, an anti-hyperglycemic drug, has been known to have antitumor properties for around 15 years. Although there are a number of reports attributing the antitumor function of metformin to its impact on energy homeostasis and oxygen re-distribution in tumor microenvironment, detailed mechanisms remain largely unknown. In the past several years, there is an increasing number of publications indicating that metformin can affect various immunological components including lymphocytes, macrophages, cytokines and several key immunological molecules in both human and animal studies. These interesting results appear to be in line with emerging data that suggest associations between immune responses and energy homeostasis/oxygen re-distribution, which may explain effective impacts of metformin on immunotherapies against autoimmune diseases as well as cancers. This review article is to analyse and discuss recent development in the above areas with aim to justify metformin as a new adjuvant for immunotherapy against human cancers. We hope that our summary will help to optimize the application of metformin for various types of human cancers.

二甲双胍是一种抗降血糖药，已知具有约15年的抗肿瘤特性。尽管有许多报道将二甲双胍的抗肿瘤功能归因于其在肿瘤微环境中对能量稳态和氧重新分布的影响，但详细的机制仍然未知。在过去的几年中，越来越多的出版物表明二甲双胍可以影响人体和动物研究中的各种免疫学成分，包括淋巴细胞，巨噬细胞，细胞因子和几种关键的免疫学分子。这些有趣的结果似乎与新出现的数据相吻合，这些数据表明免疫反应与能量稳态/氧气重新分布之间存在关联，这可能解释了二甲双胍对针对自身免疫性疾病以及癌症的免疫疗法的有效影响。这篇综述文章旨在分析和讨论上述领域的最新发展，目的是证明二甲双胍可以作为针对人类癌症的免疫疗法的新佐剂。我们希望我们的总结将有助于优化二甲双胍在各种类型的人类癌症中的应用。