N6-methyladenosine modification: an important player in the tumor immune microenvironment.

The decoration of RNA with N6-methyladenosine (m6A) is a reversible post-transcriptional modification that plays an important regulatory role in all eukaryotic life activities. The m6A modification of RNA regulates the development and progression of tumors, including bladder cancer, melanoma, Lewis lung carcinoma, and hepatocellular carcinoma. The tumor immune microenvironment (TIME) includes immune cells, cytokines, and cell surface molecules, which interact with each other and ultimately determine the flow of tumor immunity. The onset of cancer implies that the TIME has been reshaped into a pro-tumor state. The key to cancer treatment lies in reshaping the TIME to reset the anti-tumor immune response. Here, we have reviewed how RNA m6A modification affects the TIME, and discussed the merits of using m6A regulator inhibitors as an individual treatment strategy as well as in combination with immune checkpoint blockade therapy.