Yusuke Ono et al. postulated that claudin-4 and claudin-7 may be a useful immunohistochemical marker to distinguish HCC and CC, because the expression of these proteins is higher in these two cases than in control, and the expression of CLDN4 and CLDN7 is lower in HCC than in CC [97]. This evidence concerns the gene CLDN4 and cholangiocarcinoma.