The association between genetic polymorphism and the processing efficiency of miR-149 affects the prognosis of patients with head and neck squamous cell carcinoma.

MicroRNAs (miRNAs) play important roles in modulating the neoplastic process of cancers including head and neck squamous cell carcinoma (HNSCC). A genetic polymorphism (rs2292832, C>T) has been recently identified in the precursor of miR-149; nevertheless its clinicopathological implications remain obscure. In this study, we showed that miR-149 is down-regulated in HNSCC compared to normal mucosa and this is associated with a poorer patient survival. In addition, HNSCC patients with the T/T genotype have more advanced tumors and a worse prognosis. Multivariate analysis indicated that patients carried the T/T genotype have a 2.81-fold (95% CI: 1.58-4.97) increased risk of nodal metastasis and 1.66-fold (95% CI: 1.05-2.60) increased risk of mortality compared to other groups. T/T genotype also predicted the worse prognosis of buccal mucosa carcinoma subset of HNSCC. In vitro analysis indicated that exogenous miR-149 expression reduces the migration of HNSCC cells. Moreover, HNSCC cell subclones carrying the pri-mir-149 sequence containing the T variant show a low processing efficacy when converting the pre-mir-149 to mature miR-149. These findings suggest that miR-149 suppresses tumor cell mobility, and that the pre-mir-149 polymorphism may affect the processing of miR-149, resulting in a change in the abundance of the mature form miRNA, which, in turn, modulates tumor progression and patient survival.