MEX3D is an RNA-binding protein involved in post-transcriptional gene regulation, with emerging roles in disease pathogenesis and cancer biology. It binds to mRNA 3'-UTR AU-rich regions in nuclear and cytoplasmic compartments, mediating mRNA destabilization and localization 1. In prostate cancer, MEX3D is highly upregulated by PTEN loss and TMPRSS2/ERG fusion expression, driving oncogenic transformation by inducing the transcription factor TCF3, which promotes soft agar colony formation, invasion, and tumor formation in vivo 2. MEX3D demonstrates prognostic significance across multiple malignancies: in hepatocellular carcinoma, elevated MEX3D correlates with immune cell infiltration and checkpoint gene expression 3; in non-small cell lung cancer, MEX3D overexpression associates with worse overall survival 4; and in glioma, MEX3D emerges as an independent predictor of poor survival with functional roles in cell proliferation, migration, and invasion 5. Beyond cancer, MEX3D dysregulation occurs in neurofibromatosis type 1-derived induced neurons with autism spectrum disorder comorbidity 6, and variants in MEX3D associate with atypical femoral fractures in bisphosphonate-treated patients 7. Additionally, MEX3D participates in post-transcriptional regulatory networks controlling epithelial-mesenchymal transition in pterygium 8 and serves as a component of serum biomarkers for preeclampsia detection 1. These findings position MEX3D as a multifunctional oncogenic driver and potential therapeutic target across diverse disease contexts.