N⁶-methyladenosine (m⁶A) is the most abundant RNA modification; m⁶A modifications are installed by methyltransferases, removed by demethylases and recognized by reader proteins. M⁶A plays crucial roles in a variety of biological processes by regulating target RNA translation, splicing, nuclear export, and decay. Since the establishment of methylated RNA immunoprecipitation-sequencing methodology, over three hundred articles about m⁶A modulators, including "writers", "erasers" and "readers", have been reported in the last four years. In addition, an increasing number of molecular mechanisms underlying m⁶A RNA methylation in human cancers have been comprehensively clarified. The recently emerged molecular mechanisms of m⁶A modulators in cancer cell proliferation, cell cycle progression, migration and invasion, apoptosis, and autophagy remain to be summarized. Hence, this review specifically summarizes these recent advances in the understanding of m⁶A molecular mechanisms in tumorigenesis and cancer progression. In addition, we discuss the prospect of using an m⁶A methylation modulator as a new diagnostic biomarker and therapeutic target for human cancers.