Biomarkers that are most commonly used for this purpose include mesothelial (calretinin, D2-40, WT1 and cytokeratin 5/6), epithelial (Claudin 4), and adenocarcinoma markers (Ber-EP4, TTF-1, CEA, MOC31, Napsin A) [18]. Here, NAPSA is linked to adenocarcinoma.