Total and lipid-bound plasma sialic acid as diagnostic markers in colorectal cancer patients: correlation with cathepsin B expression in progression to Dukes stage

PURPOSE: Serum cathepsin B (CB), Total Sialic acid (TSA), total sialic acid (TSA) and lipid bound sialic acid (TSA) concentrations more useful than the other markers investigated for detecting different malignancies. Our aim was to investigate the possible correlation between serum CB with TSA, LSA in colorectal carcinoma with pathological stages progressed of the disease. METHODS: The study was performed on 177 patients (109 patients with colon and 68 patients with rectal) and 50 healthy individuals comprised the control group. Serum CB activity was determined using fluorogenic substrate. Serum TSA and LSA Concentrations were measured according to the method described by Katopodis. RESULTS: Plasma CB and TSA levels in the tumor group were significantly increased in comparison with the controls group (P < or = 0.0001). No significant differences were observed in LSA level between the tumor group and the controls group. T/N ratios for CB, TSA elevated 2.3-fold, 2.5-fold respectively). LSA 1.8-fold. Serum CB activity, TSA concentrations values in plasma samples of patients were increased significantly with pathological stages progressed (P < or = 0.0001). CB is seen to correlate more strongly with TSA in tumor group (P < or = 0.0001, r= 0.7277) in comparison with controls group. These correlations became more significant as the stage of the disease progressed. CONCLUSION: The present investigations indicate that CB activity, serum TSA, concentrations are sensitive markers for detecting and earliest diagnosis of colorectal cancer. These markers with other clinical and biochemical criteria may play important metabolic roles in cancer progression.