A New Early Colorectal Cancer Diagnostic Method: Blood Micro RNA-21 Levels

National Cancer Institute Journal findings suggest blood levels of a DNA fragment called microRNA may be a biomarker for colorectal cancer course and early diagnosis.

According to the latest data published by the World Health Organization, approximately 1 million colorectal cancer cases are diagnosed worldwide, and half of these carry a risk of death. Researchers are working intensively to develop new methods for detecting such a dangerous cancer while it is still treatable, in other words, at an early stage.

Although miR21 and miR31 (another microRNA) are known to be tumor-suppressor genes, their potential role as biomarkers in colorectal cancer has not yet been established. To evaluate both microRNAs, blood samples were taken from 12 patients with colorectal cancer or polyps and 12 people in the control group (without colorectal cancer or polyps). After concluding that miR-21 was present in colorectal cancer cell lines, a miRNA serum sample was prepared for patients with colorectal cancer.

To validate the research, the miRNA serum sample was applied to 186 colorectal cancer patients, 60 postoperative colorectal cancer patients, 43 patients with advanced adenoma, and 53 people from the control group. In colorectal cancer tissue, 166 matched samples were used to analyze miR-21. In patients with polyps or colorectal cancer, miR-21 levels increased significantly and fell after surgery. Blood miR-21 levels were also found to differ in controls compared with patients with colorectal cancer or polyps. Overall, in %92 of colorectal cancer patients and %82 of patients with advanced polyps, blood miR-21 levels were identified; the relationship between tumor size, distant spread, mortality risk, and increased miR-21 levels was established.

Based on the findings, researchers concluded that miR-21 has the potential to be a biomarker for the course and early diagnosis of colorectal cancer. Colonoscopy is currently standard in fewer than half of patients undergoing colorectal cancer screening. Even a simple blood test could change screening outcomes and benefit many more colorectal cancer patients. Whether miR-21 qualifies as a biomarker for this cancer is being evaluated, and research continues.