TNN (tenascin N) is an extracellular matrix protein with critical roles in neural development and auditory function. The protein functions as a ligand for integrin heterodimers (ITGA8:ITGB1, ITGAV:ITGB1, and ITGA4:ITGB1), mediating cell-matrix interactions essential for neurite outgrowth and cell migration 1. In the auditory system, tenascin-W (TNN) is primarily expressed in spiral ganglion neuron cytoplasm and is essential for sensory neuron development; heterozygous loss-of-function variants cause progressive hearing loss with reduced spiral ganglion neuron density, while homozygous knockout is embryonic lethal in mice 2. Compound heterozygous missense mutations in TNN (c.G736A p.G246S and c.C2954T p.T985M) have been identified as the genetic cause of autosomal recessive nonsyndromic auditory neuropathy in affected pedigrees 2. Beyond auditory function, TNN supports angiogenesis in tumors through endothelial cell elongation and sprouting, and is expressed in mammary tumors where it facilitates breast cancer cell migration and tumorigenesis 1. Thus, TNN represents a multifunctional extracellular matrix protein critical for normal neural and auditory development with pathogenic implications in both inherited deafness and cancer progression.