Expression of microRNA 638 and sex-determining region Y-box 2 in hepatocellular carcinoma: Association between clinicopathological features and prognosis

The aim of the present study was to determine the expression profile of microRNA 638 (miR-638) and sex-determining region Y-box 2 (SOX2) in hepatocellular carcinoma (HCC), and to investigate their association with clinicopathological features and survival. Reverse transcription-quantitative polymerase chain reaction analysis was used to investigate miR-638 and SOX2 expression in 78 patients with HCC. Western blot and immunohistochemical analyses were performed in order to determine SOX2 protein expression in HCC samples. Combined with the clinical postoperative follow-up data, the expression of miR-638 and SOX2 and the association between this and the prognostic values of patients with HCC were statistically analyzed. The results of the present study confirmed that miR-638 expression in tumor tissues was significantly downregulated (P < 0.001), while SOX2 expression was significantly increased, compared with healthy control tissues (P < 0.05). In addition, a significant inverse correlation between miR-638 and SOX2 expression was also observed in the HCC tissues (r = -0.675; P< 0.05). Clinicopathological correlation analysis demonstrated that reduced miR-638 and elevated SOX2 expression was significantly associated with the Tumor-Node-Metastasis stage and portal vascular invasion (P < 0.05). However, no significant differences were observed in other clinicopathological features, including age, sex, tumor size, tumor differentiation and hepatitis status (P > 0.05). Notably, follow-up analysis revealed that patients with HCC with low miR-638 expression and high SOX2 expression tended to have a significantly shorter postoperative survival time (P < 0.001). It was concluded that miR-638 may serve a vital role in the occurrence and progression of HCC by regulating SOX2 expression and thus, that miR-638 and SOX2 may be critical as novel diagnostic and prognostic biomarkers for HCC.