M⁶A is the most prevalent modification among epigenetics. M⁶A occurs on different sites of RNA and exerts important functions in specific circumstances, such as mRNA splicing, stability, nuclear export, translation or damage response. Different aspects of the concrete machinery of m⁶A modification have been studied, including its writing, erasing and reading capabilities. The molecular and biological functions of the m⁶A modification and enzymes, as well as their functions in different cancers have been substantially published. The present review summarizes these findings and provides clear description of the problems involved. The probable roles of m⁶A modification may acts on other cancers, suggesting that it may be a treatment target for these cancers.