Expression of chloride intracellular channel protein 1 (CLIC1) and tumor protein D52 (TPD52) as potential biomarkers for colorectal cancer

Objectives Unequivocal biomarkers are needed to predict susceptibility and progression of colorectal cancer. Design and methods Paired samples of tumor and normal tissue from six patients with colorectal cancer of different localization, pTNM stage and grade were employed in the present study. MS analysis was used to identify differentially regulated proteins after 2-DE separation and densitometric analysis. Results Densitometric analysis revealed differential abundance of 55 spots in tumor as compared to normal tissues. Thirty nine out of 55 spots were unambiguously identified by MS representing 32 different proteins. CLIC1, TPD52 and FABPL were consistently overexpressed (> 3-fold, P < 0.05) in all tumor tissue samples, while TPM1, TPM2, TPM3, TAGL and MLRN were consistently down-regulated (> 3-fold, P < 0.05) compared to normal tissue. Conclusions CLIC1 and TPD52 were significantly (P < 0.05) up-regulated in all cases of colorectal cancer investigated, irrespective of localization, pTNM stage and grade of colon cancer highlighting their potential to serve as new biomarkers.