FAT2 (FAT atypical cadherin 2) is a cell adhesion molecule that plays critical roles in cellular migration, synaptic integrity, and cerebellar function. FAT2 directly binds Cbln1, a secreted molecule essential for synapse formation and plasticity at Purkinje cell synapses 1. This interaction is crucial for maintaining synaptic strength of parallel fiber synapses in the cerebellum, as Fat2 deletion mice show selective weakening of these synapses and impaired motor behaviors 1. The protein is involved in regulation of cell migration and may mediate organization of parallel fibers during cerebellar development 2. In disease contexts, FAT2 mutations are associated with spinocerebellar ataxia 45 (SCA45), an autosomal dominant cerebellar ataxia 3. FAT2 is frequently mutated in esophageal squamous cell carcinoma, where it contributes to dysregulation of the Hippo signaling pathway 45. Interestingly, in uterine corpus endometrial carcinoma, FAT2 mutations are associated with better prognosis and enhanced responsiveness to immunotherapy 6. Recent research has identified FAT2 as a potential therapeutic target in squamous cancers, where it regulates cell growth and adhesion through integrin-PI3K signaling 7.