m6A modification of non‑coding RNA: Mechanisms, functions and potential values in human diseases (Review)

N6‑methyladenosine (m6A) RNA modification represents a pivotal and novel post‑transcriptional modification in eukaryotic RNAs. Initially identified in messenger RNAs (mRNAs), m6A modification on these transcripts regulates a spectrum of essential cellular processes, including mRNA splicing, subcellular localization, stability and translation. Recent studies have highlighted the involvement of m6A methylation in both biological and pathological processes, particularly in cancer. Non‑coding RNAs (ncRNAs), a diverse class of RNA molecules that do not encode proteins, encompass microRNAs, long ncRNAs and circular RNAs. Notably, m6A has been recognized as a reversible epigenetic modification within ncRNAs, a discovery that has garnered considerable attention. This modification not only influences the stability of ncRNAs but also endows them with the novel capacity for peptide translation. The differential and specific expression pattern in diseases give these m6A‑modified ncRNAs potential as biomarkers for molecular diagnostics and targeted therapy, and using ncRNA‑encoded peptides as a target for immunotherapy has also been attempted. This review synthesizes the current understanding of m6A modifications in ncRNAs, explores the effects of m6A on ncRNA function and presents the latest insights into the role of ncRNA m6A modifications in disease progression.