Two different somatic nonsense mutations were identified in 2/17 (11.8%) analyzed cases, both with the biallelic inactivation of the gene and creating a premature stop codon near to the N-terminal region of the FAT3 protein, suggesting the FAT3 gene as a putative tumor suppressor gene in parathyroid carcinogenesis, possibly regulating the Wnt signaling. This evidence concerns the gene FAT3 and neoplasm.