ABCB5. a member of the ATP-binding cassette (ABC) transporter family, is a transmembrane protein initially identified for its role in chemoresistance by effluxing therapeutic agents. It is expressed in normal tissues like skin, ocular epithelium, and gastrointestinal tract, where it regulates cell differentiation and stem cell maintenance. However, ABCB5 gained prominence as a biomarker for tumor-initiating cells (TICs) in cancers, particularly melanoma. Studies show ABCB5+ cancer cells drive tumor progression, metastasis, and therapy resistance due to enhanced drug extrusion and stem-like properties.
ABCB5-specific antibodies, developed to target extracellular epitopes, have become critical tools for research and diagnostics. These monoclonal antibodies enable precise detection of ABCB5 expression via flow cytometry, immunohistochemistry, or immunofluorescence, aiding in cancer cell isolation and characterization. Clinically, ABCB5 expression correlates with poor prognosis in melanoma, colorectal cancer, and glioblastoma, making it a potential biomarker for patient stratification.
Therapeutically, anti-ABCB5 antibodies are explored to inhibit ABCB5-mediated chemoresistance or directly target cancer stem cells. Preclinical models demonstrate that blocking ABCB5 enhances chemotherapy efficacy. Additionally, antibody-drug conjugates (ADCs) or bispecific antibodies leveraging ABCB5’s surface expression are under investigation. Notably, ABCB5’s immunomodulatory role in regulatory T cells (Tregs) suggests potential synergy with immune checkpoint inhibitors. Early-phase trials for ABCB5-targeted therapies, particularly in refractory melanoma, highlight its translational relevance. Overall, ABCB5 antibodies bridge mechanistic insights into cancer stemness with emerging diagnostic and therapeutic applications. (298 words)