Olstad et al(11) originally reported that FXYD6 mRNA was upregulated in osteosarcoma target cell lines compared with normal osteoblasts, and our previous study also showed that FXYD6 mRNA was overexpressed in CC tissues compared with normal bile duct tissues (12), suggesting that FXYD6 may be involved in tumor initiation. This evidence concerns the gene FXYD6 and cholangiocarcinoma.