Significance of correlation between levels of carcinoembryonic antigen and carbohydrate antigen 19-9, carcinoembryonic antigen and C-reactive protein, carcinoembryonic antigen and alpha-1 antitrypsin in gastric and colon cancer patients

Aim: Recent progress in proteomics studies profiled that serum proteins of cancer patients and those of normal individuals have altered cancer antigen and acute phase protein expression for distinct types and stages of cancer. In our study, correlation between carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 19-9, CEA and C-reactive protein (CRP), CEA and alpha-1 antitrypsin (A1AT) were evaluated in gastric and colon cancer patients. Materials and Methods: CEA was estimated by solid phase, two-site sequential chemiluminescent immunometric assay, CA19-9 by solid phase enzyme-linked immunosorbent assay, CRP by latex turbidimetry method and A1AT by turbidimetry method. Results: A significant correlation was seen in levels of CEA and CA19-9 in gastric (r = 0.457, P < 0.001) and colon cancer (r = 0.451, P < 0.001) patients. Correlation between CEA and CRP was significant in gastric (r = 0.462, P < 0.001) and colon cancer (r = 0.759, P < 0.001) patients and between CEA and A1AT also, correlation was found to be significant in gastric (r = 0.631, P < 0.001) and colon cancer patients (r = 0.516, P ≤ 0.001). Conclusion: Serum acute-phase protein concentrations, when combined with CEA increases the sensitivity of CEA and provide substantial information concerning the diagnosis of gastrointestinal cancers. They have a definite role as a significant prognostic indicator which undoubtedly correlates with progression of cancer. Combined CEA and CA19-9 positivity reflected more biologic malignant properties and were significantly correlated with lymph node metastasis, hepatic metastasis and lower rates of curative resection. Surgical outcomes of patients who were CEA and CA19-9 positive were poorer than those of patients with normal CEA and CA19-9 levels.