DKK1 and bile duct neoplasm: However, DKK1 expression was not correlated with age (P = 0.116), sex (P = 0.142), capsular invasion (P = 0.292), portal vein tumor thrombi (P = 1.000), bile duct tumor thrombi (P = 0.424), lymphatic metastasis (P = 1.000), tumor stage (P = 0.238), histological grade (P = 0.531), serum alpha fetoprotein level (P = 1.000), serum CA19-9 level (P = 0.698), serum CA125 level (P = 0.707), or extrahepatic metastasis (P = 0.620).