Moreover, cytokeratin 20 (CK20) is expressed in nearly 100% of urachal adenocarcinomas and is frequently accompanied by CDX2 positivity, serving as a crucial immunophenotypic marker for distinguishing enteric from non-enteric adenocarcinomas and clarifying tumor origin (30, 36, 68). This evidence concerns the gene KRT20 and bladder urachal adenocarcinoma.