ARHGAP23 encodes a Rho GTPase-activating protein that inactivates Rho-family GTPases by promoting their conversion to a GDP-bound state 1. The gene produces two isoforms through alternative splicing: a 1491-amino acid isoform 1 and a 1144-amino acid isoform 2 with C-terminal truncation 1. ARHGAP23 contains conserved PDZ, pleckstrin homology, and RhoGAP domains characteristic of the ARHGAP family 1. In cellular function, ARHGAP23 localizes to adherens junctions where it suppresses RhoA activation in the cytoplasm, thereby preventing stress fiber formation and opposing cortical actin ring formation 2. ARHGAP23 has emerging clinical significance in multiple malignancies. Pan-cancer analysis identified ARHGAP23 expression abnormalities in over 10 tumor types, with associations to prognosis, DNA methylation, and immune cell infiltration 3. Exome-wide association studies enriched ARHGAP23 for rare damaging variants in papillary thyroid carcinoma risk 4, and the gene was identified in field-cancerization studies of urothelial carcinoma 5. Additionally, ARHGAP23 variants showed suggestive association with word reading ability in neurodevelopmental studies, consistent with its role in neuronal migration and axon pathfinding 6. These findings support ARHGAP23 as a potential prognostic biomarker and therapeutic target in cancer.