Long non-coding RNAS: Molecular functions, mechanisms, and clinical implications

Long non-coding RNAs (lncRNAs) have emerged as a major class of regulatory RNA molecules with crucial roles in gene regulation, development, and disease. Although they lack protein-coding potential, lncRNAs account for a significant proportion of the mammalian transcriptome and exhibit remarkable tissue, developmental stage, and cell-type specificity. Advances in large-scale genome and transcriptome projects have overturned the notion of “junk DNA,” revealing that lncRNAs participate in diverse biological processes, including chromatin remodeling, transcriptional and post-transcriptional regulation, genomic imprinting, X-chromosome inactivation, and cellular differentiation. This review provides a comprehensive overview of the molecular characteristics, structural features, classification, and functional mechanisms of lncRNAs. Special emphasis is placed on their involvement in normal development, epigenetic regulation, and pathological conditions, particularly cancer. The emerging role of lncRNAs as diagnostic, prognostic, and therapeutic biomarkers is discussed, including their detection in circulating body fluids and their relevance in veterinary oncology such as horn cancer in cattle. Finally, current challenges and future prospects in lncRNA research are highlighted, underscoring their potential as novel targets for epigenetic intervention and precision medicine in both human and animal health.