Circulating miR-31-5p may be a potential diagnostic biomarker in nasopharyngeal carcinoma

Aberrant expression of miR-31-5p has been detected in various cancers and plays a significant role in tumorigenesis. Low miR-31-5p expression was present in nasopharyngeal carcinoma (NPC) tissues and cell lines and acted as a tumor suppressive miRNA. Currently, circulating miRNAs are emerging as novel biomarkers for the early diagnosis of cancers using a non-invasive method. However, circulating miR-31-5p has rarely been reported in NPC. Therefore, the aim of this study was to explore peripheral blood miR-31-5p levels as a noninvasive biomarker and evaluate its clinical value for the early diagnosis of patients with NPC. A total of 110 participants were recruited, including 55 NPC patients and 55 healthy controls. Peripheral blood samples were collected from these participants, and total RNA was extracted to quantify the relative expression of miR-31-5p by RT-qPCR. We found a significantly lower expression of miR-31-5p in the NPC patients than in the healthy controls. Furthermore, low expression of miR-31-5p was highly correlated with tumor-node-metastasis (TNM) stage (I+II vs III+IV, p=0.001), T classification (T1 vs T2+T3+T4, p=0.036) and local lymph node metastasis (N1-N3 vs N0, p=0.002), but not distant metastasis (p=0.288). Moreover, miR-31-5p showed a moderate diagnostic performance (AUC=0.866, sensitivity = 0.782, specificity = 0.818). Thus, we concluded that circulating miR-31-5p can be a potentially novel and non-invasive biomarker for the early diagnosis of NPC and an attractive therapeutic target in NPC patients.