KRT36 is a type I hair keratin encoded on chromosome 17 that functions as a structural component of epithelial tissues, particularly in hair cortex differentiation and filiform papilla formation 1. As part of the intermediate filament cytoskeleton, KRT36 contributes to epithelial cell differentiation and tissue morphogenesis 2. In normal human tongue, KRT36 is specifically expressed in filiform papillae of the dorsal surface and is also detected in nail beds, thymus, and hair cortex 1. KRT36 expression is significantly downregulated in squamous cell carcinoma of the mobile tongue and in clinically normal tongue tissue adjacent to tumors, suggesting its role as a biomarker for pre-neoplastic changes 13. At the molecular level, KRT36 is subject to ubiquitin-mediated protein degradation; the E3 ligase RNF187 promotes cell proliferation in spermatogonia by targeting KRT36/KRT84 for lysine 48-linked polyubiquitination and degradation 4. Clinically, KRT36 loss may indicate neoplastic transformation in tongue epithelium, while its restoration or stabilization could represent a therapeutic target for tongue squamous cell carcinoma and infertility associated with spermatogonia dysfunction 14.