Could myeloperoxidase be a biomarker or predictor for colorectal cancer?

Abstract

Aim: Colorectal cancer (CRC) is the 4th most common cancer, and tumor tissue has a higher amount of myeloperoxidase (MPO)-positive cells than normal tissue. We aimed to compare the parameters of myeloid and lymphoid cells and MPO levels in the venous blood of patients diagnosed with CRC and healthy volunteers. Materials and methods: The patient group in the study consisted of people who were diagnosed with CRC and had not yet received local or systemic treatment. The control group was selected from non-cancer patients. The enzyme-linked immunosorbent assay was used for the quantitative determination of MPO in serum. Results: A total of 56 patients were included in this study. The mean MPO level of the patient group was significantly lower than that of the control group (3.59, 5.2 pg/mL, p=0.007). As a result of the receiver operating characteristics curve analysis, the cut-off point obtained for MPO was determined to be 3.66. There were significantly more CRC patients in the group with an MPO value of 3.66 and below (p=0.001; p<0.01). An MPO value of 3.66 or below increased the risk of CRC by 8.13 times. Conclusions: In our study, the serum MPO level was significantly lower in the CRC patients, suggesting that immune system cells in CRC tend to behave differently in cancerous tissue and the general circulatory system. In the light of future studies on this subject, simple and easily reproducible determination of plasma MPO level may help to predict the prognosis, treatment planning, response to treatment, and efficacy of immunotherapy in CRC. Keywords: Colorectal cancer, myeloperoxidase, predictor