ST18 is a C2H2-type zinc finger transcription factor that functions as a transcriptional repressor and tumor suppressor. It binds to DNA sequences containing bipartite elements of direct repeats of 5'-AAAGTTT-3' separated by 2-9 nucleotides 1. ST18 regulates proapoptotic and proinflammatory gene expression, mediating TNF-α-induced transcription of pro-inflammatory cytokines (TNF-α, IL-1α, IL-6) in fibroblasts 1. In breast cancer, ST18 functions as a tumor suppressor through epigenetic silencing. The gene is significantly downregulated in breast cancer cell lines and primary tumors, with approximately 80% of breast cancer samples showing hypermethylation of the ST18 promoter 2. Ectopic ST18 expression strongly inhibits colony formation in breast cancer cells and suppresses tumor formation in xenograft models 2. Recent studies demonstrate that the lncRNA ST18-AS1 enhances ST18 mRNA stability through FUS-mediated regulation, and this pathway suppresses pancreatic cancer cell proliferation and promotes apoptosis 3. Clinically, ST18 polymorphisms are associated with autoimmune diseases. The risk allele A in rs2304365 significantly increases pemphigus susceptibility and disease severity in Iranian populations 4. Additionally, ST18 variants are implicated as susceptibility loci for primary angle closure glaucoma in GWAS studies 56.