Expression of EGFR or HER2 is known to be a prognostic factor in some cancers (Gusterson et al, 1992; Nicholson et al, 2001), but no previous study has clarified the influence of these molecules on prognosis in cholangiocarcinoma (Ito et al, 2001; Altimari et al, 2003; Nakazawa et al, 2005), probably because cholangiocarcinoma is a relatively rare cancer and collection of a large cohort is difficult. The gene discussed is ERBB2; the disease is cholangiocarcinoma.