Using micro-dissection to isolate areas of ductular reaction from human PBC samples, Spee et al. demonstrated that NOTCH2, JAG1 and JAG2 mRNA expression was significantly elevated in PBC livers in a manner analogous to that previously seen in bile duct development and in PSC (Spee et al., 2010; Nijjar et al., 2001, 2002). Here, JAG2 is linked to primary biliary cholangitis.