Abstract: Objective To investigate the expression of microRNA-361-5p （miR-361-5p） in oral squamous cell carcinoma （OSCC） and its relationship with clinicopathological features and prognosis. Methods From January 2012 to December 2015 in our hospital， 84 cases of OSCC were collected for measurement of miR-361-5p by real-time quantitative PCR （QPCR）. The relationship between miR-361-5p expression and clinicopathological features of OSCC was analyzed. Kaplan-Meier method was used for survival analysis， and 69 cases of normal oral mucosa in the same period were chosen as control. The receiver operating characteristic curve （ROC） was used to evaluate the effectiveness of tissue miR-361-5p levels in the early diagnosis of OSCC. Results The expression of miR-361-5p in OSCC was 0.306±0.024， lower than 1.054±0.040 of normal oral mucosa， and the difference was statistically significant （P=0.001）. The expression of miR-361-5p in OSCC was not related to age， sex， smoking and T staging， but was related to the degree of differentiation， clinical stage and lymph node metastasis （P<0.05）. In the patients with middle and high differentiation， clinical stage Ⅰ／Ⅱ and no lymph node metastasis， the expression levels were 0.356±0.028， 0.391±0.033 and 0.450±0.036， higher than 0.121±0.008 of poorly differentiated carcinoma， 0.168±0.016 of stage Ⅲ／Ⅳ and 0.168±0.013 of lymph node metastasis， and the difference was statistically significant （P<0.001）. ROC curve analysis showed that area under the curve （AUC） of miR-361-5p in diagnosis of OSCC was 0.966 （95%CI： 0.939-0.993）， while AUC in diagnosis of OSCC with different clinical stages，lymph node metastasis and differentiation were 0.841 （95%CI：0.757-0.926）， 0.925 （95%CI：0.869-0.979） and 0.907 （95%CI：0.844-0.971），indicating a good diagnostic value of the tissue level of miR-361-5p for OSCC. The median OS of the whole group was 24.65 months，irrespective of age，sex，smoking， T stage and lymph node metastasis，but was related to the degree of differentiation，clinical stage and expression of miR-361-5p. Median OS at high miRNA-361-5p level was 29.90 months， longer than 18.70 months at low level，with a statistically significant difference （P<0.001）.
ConclusionLow expression of MiR-361-5p is closely related to the occurrence and development of OSCC and the prognosis of patients with lower miR-361-5p levels were poor.