TSN (translin) is a multifunctional, evolutionarily conserved protein containing tandem staphylococcal nuclease domains and a tudor domain 1. It exhibits both single-stranded and double-stranded endoribonuclease activity and facilitates siRNA processing by acting as an activator of RNA-induced silencing complex (RISC) through endonucleolytic cleavage of the siRNA passenger strand 1. Beyond RNA silencing, TSN functions as a scaffolding molecule in multiprotein complexes and is involved in virtually all pathways of gene expression, from transcription to post-transcriptional regulation 1. Clinically, TSN demonstrates dual relevance. It acts as a transcriptional regulator sensing intracellular L-arginine levels to promote T cell survival and anti-tumor immunity 2, suggesting therapeutic potential in immunotherapy. Conversely, increased TSN expression is closely associated with various cancer types, making it an attractive anti-cancer therapy target and potent tumor marker 1. TSN is essential for normal development and stress resistance, underscoring its fundamental cellular importance 1. Its role in balancing immune function and cancer-related processes positions TSN as a critical node in cellular regulation with significant implications for both cancer treatment and immunotherapeutic approaches.