Expression of Let-7d MicroRNA in Colorectal Cancer Patients

Micro-ribonucleic acids (microRNAs) have introduced a new field in the molecular diagnosis of cancer. However, the role of circulating microRNAs in the plasma/serum of colorectal cancer patients is still unclear. This study was conducted to determine the expression of let-7d microRNA in patients with colorectal cancer.

This case-control study was conducted on 40 patients with colorectal cancer and 40 healthy people. In this study, 7 mL blood samples were collected from patients with colorectal cancer (both before and after tumor resection) and healthy individuals (only once). The serum samples were isolated and stored at - 80°C until molecular analysis. MicroRNAs were extracted from serum samples, and cDNA was synthesized. Let-7d expression was examined using the RT-qPCR method. Data were analyzed using GraphPad Prism v. 9 software. The receiver operating characteristic (ROC) curve analysis, sensitivity, and specificity were also calculated for the let-7d microRNA data to introduce a diagnostic biomarker between the preoperative patient group and the control group.

In the preoperative samples of the patients, the expression of let-7d microRNA was significantly lower than that of the control group (P˂0.05). The expression of let-7d microRNA significantly increased after tumor resection compared to before. The ROC analysis for let-7d microRNA in the preoperative patient group with the control group showed that the sensitivity was 33.3%, specificity was 92.3%, and the area under the curve (AUC) was 0.622.

Let-7d microRNA could potentially serve as a new noninvasive diagnostic biomarker for the early detection of colorectal cancer. However, further studies are required on this subject.