The heterogeneous nuclear ribonucleoprotein L (HNRNPL) is a member of the hnRNP family, which plays critical roles in RNA metabolism, including splicing, transport, stability, and translation. HNRNPL specifically binds to RNA sequences rich in CA repeats or other specific motifs, regulating alternative splicing of genes involved in diverse cellular processes such as DNA repair, angiogenesis, and immune responses. Dysregulation of HNRNPL has been linked to cancers (e.g., prostate, breast), neurological disorders, and autoimmune diseases. Antibodies targeting HNRNPL are essential tools for studying its molecular functions, localization, and interactions. They are widely used in techniques like Western blotting, immunoprecipitation, and immunofluorescence. In clinical contexts, anti-HNRNPL autoantibodies have been identified in autoimmune conditions, including systemic lupus erythematosus (SLE), where they may serve as diagnostic or prognostic biomarkers. However, commercial HNRNPL antibodies vary in specificity, requiring careful validation to avoid cross-reactivity with other hnRNP family members. Research continues to explore HNRNPL's role in disease mechanisms and its potential as a therapeutic target.