Abstract 1902: Novel monoclonal antibodies specific for cancer-associated proliferating cellular nuclear antigen for tumor monitoring and diagnosis

Abstract Proliferating cellular nuclear antigen (PCNA) is a biomarker associated with cancer progression and is expressed in all cancer types. Its expression is increased before DNA synthesis with the transition of cells from G1 to S phase, making it a useful diagnostic marker for tumor cell proliferation. Our lab has identified an acidic and basic isoform of PCNA that can be resolved using 2-dimensional gel electrophoresis (2DE). Cancer cells express the acidic, cancer-associated isoform of PCNA (caPCNA), whereas healthy cells only express the basic, non-malignant isoform of PCNA (nmPCNA). Thus, caPCNA is an important biomarker that can be used for identifying early-stage cancer and monitoring tumor growth, metastasis, and response to treatment. Immunohistochemical staining (IHC) of tissue biopsies is an essential method for tumor detection and monitoring of cancer progression. Antibodies are used either individually or in panels and typically require markers that are specific to each tumor’s origin. Because caPCNA is not specific to a single cancer type, it is a universal biomarker which can be used to monitor cancer of any origin. Commercially available antibodies for PCNA do not distinguish between the cancer isoform and the non-cancer associated normal isoform. We have developed a series of monoclonal antibodies that are capable of distinguishing caPCNA from nmPCNA and have characterized these antibodies using 2DE and IHC. These novel monoclonal antibodies targeting the caPCNA isoform could enable pathologists to distinguish the presence of cancer cells in difficult to diagnose biopsy specimens, more efficiently monitor surgical margins, and potentially identify the presence of circulating tumor cells in blood samples. Citation Format: Malaney C. Young, Caroline M. Li, Robert G. Lingeman, Chun Li, Aimin Li, Linda H. Malkas, Robert J. Hickey. Novel monoclonal antibodies specific for cancer-associated proliferating cellular nuclear antigen for tumor monitoring and diagnosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1902.