Characterization of an autoantigen associated with chronic ulcerative stomatitis: The CUSP autoantigen is a member of the p53 family

A unique clinical syndrome has been described in which patients have chroni c oral ulceration and autoantibodies to nuclei of stratified squamous epith elium. We have characterized the autoantibodies from patient sera and found that the major autoantigen is a 70 kDa epithelial nuclear protein. Sequenc ing of the cDNA for this protein, chronic ulcerative stomatitis protein, re vealed it to be homologous to the p53 tumor suppressor and to the p73 putat ive tumor suppressor, and to be a splicing variant of the KET gene. The p53 -like genes, p73 and the several KET splicing variants, are recently descri bed genes of uncertain biologic and pathologic significance. This study pro vides the first clear association of a p53-like protein with a disease proc ess.