Identifying High-Risk Stage II Colon Cancer Patients: A Three-MicroRNA-Based Score as a Prognostic Biomarker

Adjuvant treatment for patients with stage II colon cancer remains controversial. We testeda panel of microRNAs to identify high-risk stage II colon cancer patients who would potentially benefit from postoperative chemotherapy. We constructed a simple 3-microRNA-based score that can predict the prognosis in this subset of patients. Background: The potential benefit of adjuvant chemotherapy in surgically resected patients with stage II colorectal cancer is controversial. The current guidelines, which are based solely on clinical factors, have limited usefulness, and a clear need exists for biomarkers to supplement the clinical information. MicroRNAs (miRNAs) have previously been shown to be useful cancer biomarkers. In the present study, we assessed the usefulness of a miRNA score to help identify the subset of high-risk patients likely to benefit from adjuvant chemotherapy. Patients and Methods: Six miRNAs previously identified as prognostic markers in Asian patients (miR-21-5p, miR-20a-5p, miR-103a-3p, miR-106b-5p, miR-143-5p, and miR-215) were studied in tumor samples from 71 white patients with stage II colon cancer. Results: Three miRNAs (miR-103a-3p, miR-143-5p, and miR-215) emerged as independent prognostic markers on multivariate analysis and were used to construct a miRNA-based score that classified patients into high and low-risk groups. The patients in the high-risk group had significantly shorter disease-free survival compared with their low-risk counterparts (P = .003). The time-dependent receiver operating characteristic curve analysis showed that our 3-miRNA score improved the prediction of outcome when added to the clinical features (P = .023). Conclusion: Our 3-miRNA score added valuable prognostic information to the clinical features in stage II colon cancer. Further research in this field could provide useful tools to determine whether adjuvant chemotherapy would benefit patients with stage II colon cancer after surgery.