OCLN and alkaline phosphatase measurement: Here, we review the major modes and factors of cell–cell adhesion related to the pathogenesis of AP and CP: tight junctions [occludin, tricellulin, claudin, junctional adhesion molecules (JAMs), and zonula occludin (ZO)], adherens junctions (E-cadherin and p120-, α-, and β-catenin), and other adhesion molecules (selectins and ICAMs) (Fig. 1, Table 1).