CEACAM5 and cancer: Although serum concentrations of carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 19-9 are commonly measured to detect and monitor of ICC, insufficient sensitivity and specificity has been a problem with using these established markers in this form of cancer (Kawarada and Mizumoto, 1984, 1990; Wang et al, 1994; Yamanaka et al, 1995; Nakamura et al, 1996; Chu et al, 1997; Kim et al, 1999).