Heterogeneous nuclear ribonucleoprotein K in cancer biology and its therapeutic applications (Review).

Heterogeneous nuclear ribonucleoprotein K (hnRNPK) is a multifunctional protein belonging to the heterogeneous nuclear ribonucleoprotein family. The K‑homology domain is the most evolutionarily conserved feature of hnRNPK and is responsible for RNA‑binding. hnRNPK interacts with both chromatin and RNA in numerous species. Initially characterized as an RNA‑binding protein, hnRNPK functions as a structural protein, integrating a number of signaling pathways and participating in gene expression regulation, RNA processing, cell cycle control and apoptosis. hnRNPK exhibits aberrant expression in numerous tumors, functioning paradoxically as either an oncogene or tumor suppressor depending on cellular context, expression levels and post‑translational modifications. Recent advancements have outlined the involvement of hnRNPK in tumor cell migration, angiogenesis and chemoresistance through interactions with long non‑coding RNAs and the regulation of key signaling pathways. The present review summarizes current knowledge regarding the structure, function and clinical importance of the hnRNPK in cancer, highlighting its potential as both a biomarker and therapeutic target.