RNF187 is an E3 ubiquitin-protein ligase that plays critical roles in cell proliferation, migration, and tumorigenesis through lysine 48-linked polyubiquitination of target proteins 12. The protein facilitates degradation of multiple substrates including WDR77 in spermatogonial stem cells, KRT36/KRT84 in spermatogonia, and directly ubiquitinates P53 in breast cancer cells 123. RNF187 promotes cellular proliferation and migration by relieving transcriptional repression through substrate degradation, such as enhancing EGR1 expression via WDR77 degradation 1. The protein is significantly overexpressed across 27 cancer types and correlates with poor patient prognosis, advanced TNM stage, and resistance to therapies like propranolol in infantile hemangiomas 456. RNF187 undergoes neddylation modification that prevents its own degradation and enhances its oncogenic functions through regulation of cytoskeletal proteins like IQGAP1 7. Clinically, RNF187 serves as an independent prognostic factor and potential therapeutic target, with its expression correlating with immune infiltration, tumor mutational burden, and treatment resistance across multiple cancer types 58.