The role of acute-phase reactant proteins, carcinoembryonic antigen and CA 19-9 as a marker in the preoperative staging of colorectal cancer: a prospective clinical study.

Acute-phase reactant proteins have been considered in searching for new biochemical tumor markers useful at initial diagnosis, staging and monitoring of colorectal cancer. In this study, we aimed to determine the role of acute-phase reactant proteins in combination with carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA 19-9) at the preoperative staging of colorectal cancer. In 22 patients with cancers of the colon and rectum and in 9 control patients without cancer, the serum levels of CEA, CA 19-9, C-reactive protein (CRP), alpha 1-antitrypsin (AAT) and alpha 1-acid glycoprotein (AAG) were measured. While statistical analysis did not show significant correlations between serum CEA, AAT and CRP levels with the stage of disease, the significant correlations between serum CA 19-9 and AAG concentrations with the extent of cancer were detected (p < or = 0.0197 and p < or = 0.0378, respectively). Multivariate discriminant analysis gave a final prognostic model that included serum CA 19-9 and AAG levels with a significance of p < or = 0.0089. The Linear regression analysis also gave a form of (Stage = 0.04667 + 0.0077 x CA 19-9 + 0.0068 x - AAG) for staging. We considered that the serum AAG levels, in combination with serum CA 19-9 concentrations may have an important role in the preoperative staging of colorectal cancer.