miR-21: a promising biomarker for the early detection of colon cancer

PURPOSE: The aim of this study was to compare the expression of miR-21 gene in stages II-IV of formalin-fixed paraffin-embedded (FFPE) tissue in patients with colon cancer and introduce miR-21 as a potential molecular marker for detection of colon cancer in the early stages. INTRODUCTION: Currently, identification of key molecules involved in the pathogenesis of cancer is one of the areas under consideration. miRNAs, are small RNAs which have been identified in many cancers. In this study, we investigated the expression of miR-21 in three pathologic stages in patients with colon cancer in the north of Iran. PATIENTS AND METHODS: A total of 40 FFPE samples were obtained from patients with stages II, III, and IV from hospitals in Mazandaran and Golestan provinces. After extraction of RNA, treatment with DNase I and cDNA synthesis was performed and miR-21 expression was assessed by qPCR. Then, the data were analyzed using statistical software R (3.4.3). RESULTS: The expression of miR-21 in stage II was significantly different from stage IV. However, no significant difference was observed between the other stages. In stage II, the level of miR-21 expression was higher in men than women. Moreover, in the second pathological stage, miR-21 expression was reduced in patients with adjacent lymphoid tissue engagement. In addition, the expression of miR-21 in grade I was significantly higher than grade II. CONCLUSION: The results of this study suggest that miR-21 can be a diagnostic marker for early stages of colon cancer, especially in men. It can also be considered as a good candidate for targeted treatment of colon cancer in the early stages of the disease. Furthermore, for the first time, we suggested that miR-21 can be a good molecular marker for classification of the stages of colon cancer.