HNRNPC is a ubiquitous nuclear RNA-binding protein that nucleates 40S hnRNP particle assembly and regulates gene expression at multiple levels 1. The protein binds poly-U tracts in mRNA 3' and 5'-UTRs, modulating mRNA stability and translation efficiency, with single tetramers binding 230-240 nucleotides 1. HNRNPC plays critical roles in pre-mRNA splicing and spliceosome assembly 1. As an m6A reader, HNRNPC binding is regulated by N6-methyladenosine modifications through an 'm6A-switch' mechanism, wherein m6A alters local RNA structure to facilitate HNRNPC access to its binding motifs, thereby controlling alternative splicing and gene expression 2. Disease relevance is substantial: heterozygous HNRNPC variants cause autosomal dominant intellectual developmental disorder 74, with haploinsufficiency affecting alternative splicing of multiple neurodevelopmental genes and impairing neuronal function 3. HNRNPC dysregulation promotes oncogenic processes in multiple cancers—including cervical cancer lymphatic metastasis via m6A-dependent FOXM1 splicing 4, T-cell leukemia through MYC-regulated oncogenic transcription 5, and renal cell carcinoma metastasis through alternative splicing regulation 6. Additionally, HNRNPC acts as a potent TDP-43 splicing regulator relevant to ALS/FTLD pathogenesis 7. These findings establish HNRNPC as a critical epitranscriptomic regulator with significant implications for neurodevelopmental and malignant disorders.