Based on the different genotypes of FUT3 and FUT2, which can determine the cut-off level of CA19-9, and the level of CA19-9 in 433 PSC patients, 41 of whom possessed biliary malignancy, Wannhoff et al (26) classified the PSC patients into three groups (no FUT3 activity regardless of FUT2 activity, both FUT2 and FUT3 activity, and no FUT2 activity without loss of FUT3 activity, respectively). Here, FUT3 is linked to pancreatic serous cystadenoma.