The RPAIN antibody targets the RPA-Interacting Protein (RPAIN), a critical component in DNA metabolism. RPAIN, also known as hCINAP or ASPSCR1. interacts with Replication Protein A (RPA), a single-stranded DNA-binding complex essential for DNA replication, repair, and recombination. RPAIN modulates RPA’s activity by regulating its localization and stability, influencing processes like homologous recombination and checkpoint signaling. Dysregulation of RPAIN has been linked to genomic instability and cancer progression. Antibodies against RPAIN are widely used in research to study its role in DNA damage response, particularly in contexts like chemotherapeutic resistance or tumorigenesis. These tools enable detection via techniques such as Western blotting, immunofluorescence, or immunoprecipitation, aiding investigations into RPAIN’s molecular interactions. Recent studies also implicate RPAIN in rare diseases, including alveolar soft-part sarcoma (ASPS) due to ASPSCR1-TFE3 fusion mutations. Its dual roles in maintaining genome integrity and disease pathogenesis make RPAIN a compelling target for both basic research and therapeutic exploration. Commercial RPAIN antibodies are typically developed in rabbit or mouse hosts, validated for specificity across human and model organism samples.