[A stratified framework for normal control tissue selection in ameloblastoma research]

Ameloblastoma is a locally invasive benign tumor of odontogenic epithelial origin. Research into its molecular mechanisms is hindered by the lack of unified norms for normal control tissue selection, which undermines data comparability. Current studies employ highly heterogeneous control tissues, including tooth germs, pericoronal tissue, normal oral mucosa and even commercial samples, thereby complicating data integration and potentially affecting the accurate interpretation of disease mechanisms. Based on principles of tooth development and the concept of "developmental arrest" in ameloblastoma, we propose a three-tier reference framework for normal control tissue selection: Tier 1 controls (preferred) include normal tooth germs (bell stage prioritized), reduced enamel epithelium and dental lamina remnants among other odontogenic epithelial components, which provide optimal consistency in developmental origin and stage; Tier 2 controls (alternative) consist of site-matched oral mucosa or specific odontogenic cysts linings and may be served as supplements but require explicit limitation disclosure; Tier 3 controls (not recommended), such as tissues of unknown origin or xenogeneic sources, should be avoided due to limited biological comparability. We also propose complementary quality control and normalized reporting recommendations encompassing tissue source verification, histopathological validation, and ethical compliance documentation. This reference framework establishes a reproducible and comparable strategy for controlling tissue selection in ameloblastoma research, thereby contributing to enhanced data reliability and cross-study comparability, while providing methodological reference for other odontogenic tumors and developmental disorders.