Evaluation of circulating cellular DCLK1 protein, as the most promising colorectal cancer stem cell marker, using immunoassay based methods

BACKGROUND: DCLK1, as the most potential colorectal cancer stem cell (CSC) marker has been the core of many recent investigations. However, no study has been performed to evaluate the circulating cellular DCLK1 protein (CCDP) that might reflect the presences of colorectal CSC in circulation. OBJECTIVES: We aimed to evaluate CCDP in the peripheral blood mononuclear cells (PBMCs) of colorectal cancer (CRC) patients applying immunoassay based methods including PLA, IPCR and ELISA in order to introduce the method of choice for clinical detection of CCDP. METHODS: PBMCs were extracted from blood samples of 58 CRC patients along with 58 blood samples of tumor free controls. Total protein of PBMC was extracted and the CCDP level was evaluated. The results of three applied immunoassay tests were compared and the best approach for clinical application was introduced, accordingly. In addition, the correlation of CCD Plevel with clincopathologic findings of CRC patients was assessed. RESULTS: The results of three immuneassay methods confirmed each other. Based on our finding, ELISA could be the most judicious method for clinical evaluation of CCDP considering its simplicity for clinical implications. Our results also showed a significant higher amount of CCDP in peripheral blood of CRC patients compared to control group which was also correlated with patients' clinicopathologic finding such as stage, grade and neoadjuvant history. CONCLUSION: CCDP could be applied for monitoring purposes in CRC patients. However, its application needs to be more elucidated in future investigations implementing larger samples.