Plasma microRNA-1207-5p as a Potential Biomarker for Diagnosis and Prognosis of Colorectal Cancer.

BACKGROUND: MicroRNA-1207-5p (miR-1207-5p) has been identified as a tumor suppressor in many types of cancer. In our previous research, we found that the expression of miR-1207-5p in cancer tissues and cell lines were both down-regulated, and miR-1207-5p may function as tumor suppressor in colorectal cancer (CRC). However, less research has been done with respect to the expression of plasma miR-1207-5p in CRC or colorectal adenoma (CRA). There was no research regarding the diagnostic ability nor on the prognostic value of plasma miR-1207-5p in CRC. We conducted a preliminary study on the plasma miRNA-1207-5p as a non-invasive biomarker in CRC. METHODS: Plasma miR-1207-5p expression was quantified by qRT-PCR from CRC patients (n = 64), CRA patients (n = 42), and normal controls (n = 36). The blood samples were collected after having been diagnosed by pathology but before surgical resection and radio-chemotherapy. The CRC patients were divided into low and high expression groups according to the mean expression level of plasma miR-1207-5p. The relation of expression levels of miR-1207-5p and overall survival were analyzed by Kaplan-Meier survival curves. The receiver operating characteristic (ROC) curves were generated to assess the diagnostic ability of plasma miR-1207-5p in CRC. RESULTS: The expression of plasma miR-1207-5p was obvious down-regulated both in CRC patients (mean ± SD: 0.1661 ± 0.0083) and CRA patients (mean ± SD: 0.2480 ± 0.0162) compared to normal controls. The lower the ex-pression of plasma miR-1207-5p, the stronger the association with advanced TNM stage and positive lymph node metastasis compared with the high expression group (p = 0.027, p = 0.033). The lower the expressions of plasma miR-1207-5p, the shorter the overall survival time for CRC patients (p = 0.0404). There was no significant difference in the relative expression of plasma miR-1207-5p between the preoperative group and postoperative group. ROC analysis showed that the diagnostic sensitivity and specificity were 95.31% and 94.44% (at a cutoff = 0.2990) for CRC patients, 90.48% and 80.56% (at a cutoff = 0.4060) for CRA patients, respectively. The AUC value was 0.9852 (95% CI = 0.9870 - 1.0003, p < 0.0001), and 0.9530 (95% CI = 0.9117 - 0.9944, p < 0.0001), respectively. CONCLUSIONS: Significant down-regulation of plasma miR-1207-5p was correlated with poor survival and with strong diagnostic ability and may function as a potential biomarker for diagnosis and prognosis of colorectal cancer.