ObjectiveMicroRNAs(miRNAs) belong to noncoding protein genes, which are a class of small RNAs that negatively regulate gene expression, and seral miRNAs have important clinical significance. To investigate the clinical significance of miR196a level in nasopharyngeal carcinoma (NPC), this study analyzed the relationship between the level of seral miR196a and the response to radiotherapy in NPC patients.MethodsA total of 138 NPC patients with results of the followup after treated with intensitymodulated radiotherapy (IMRT) in Xiangya Hospital from June 2010 to June 2019 were chosen as the experimental group. Fasting venous blood samples of all patients were collected before radiotherapy. In addition, fasting venous blood samples of 62 normal adults who came to the hospital for health examination were collected as controls. And the expression level of serum miR196a was detected by realtime fluorescence quantitative polymerase chain reaction (qPCR). The correlation between the high expression of seral miR196a and clinical staging related to diseasefree survival (DFS) in NPC patients was analyzed. Based on the response evaluation criteria in solid tumors and followup results, the patients were divided into Group A (complete response, CR) and Group B (partial response, PR; stable progression, SP). The relationship between the levels of seral miR196a and the efficacy of NPC radiotherapy was analyzed.ResultsMiR196a was highly expressed in 122 sera of all the 138 NPC patients (88.41%). In sera of 86 patients in advanced clinical stage (Ⅲ、Ⅳ), miR196a was highly expressed in 81 cases. In 16 patients of clinical stageⅠand 36 of clinical stage Ⅱ, miR196a was highly expressed in 14 cases and 27 cases respectively. The level of miR196a expression in serum of each NPC group was significantly higher than that in the normal group (all P<0.01). According to the effect of radiotherapy, expression of seral miR196a was high in 71 of 86 patients in Group A (82.56%), and 51 of 52 (98.08%) in Group B (PR:96.97%, 32/33; SP：100%，19/19). The difference of serum miR196a high expression between Group A and Group B was statistically significant (P<0.01). The median DFS of Group A (36 months) was significantly higher than that of Group B (10 months)(P<0.01).ConclusionsThe high expression of seral miR196a hints a poor prognosis of NPC after radiotherapy. The miR196a gene is expected to be a seral biomarker for the prognosis of NPC.