EGFR and intrahepatic cholangiocarcinoma: SOX4, which has been associated with poor survival of patients with CC, was upregulated in 29.3% (17/58) of ICC and 29.8% (28/94) of ECC cases, respectively, and SOX4 expression was closely associated with upregulation of EGFR in both ECC and ICC groups, and patients with CC upregulating both SOX4 and EGFR showed the worst survival.