mA methylation: a process reshaping the tumour immune microenvironment and regulating immune evasion.

N6-methyladenosine (mA) methylation is the most universal internal modification in eukaryotic mRNA. With elaborate functions executed by mA writers, erasers, and readers, mA modulation is involved in myriad physiological and pathological processes. Extensive studies have demonstrated mA modulation in diverse tumours, with effects on tumorigenesis, metastasis, and resistance. Recent evidence has revealed an emerging role of mA modulation in tumour immunoregulation, and divergent mA methylation patterns have been revealed in the tumour microenvironment. To depict the regulatory role of mA methylation in the tumour immune microenvironment (TIME) and its effect on immune evasion, this review focuses on the TIME, which is characterized by hypoxia, metabolic reprogramming, acidity, and immunosuppression, and outlines the mA-regulated TIME and immune evasion under divergent stimuli. Furthermore, mA modulation patterns in anti-tumour immune cells are summarized.