Prognostic significance of phosphorylated signal transducer and activator of transcription 3 and suppressor of cytokine signaling 3 expression in hepatocellular carcinoma

Altered expression of phosphorylated signal transducer and activator of transcription 3 (pSTAT3) and suppressor of cytokine signaling 3 (SOCS3) has been implicated in various types of human cancers. However, the clinical role of pSTAT3 and SOCS3 in hepatocellular carcinoma (HCC) is not well established. Immunohistochemical analysis of pSTAT3, SOCS3, Ki67 and VEGF expression was performed on tissue microarrays from 138 HCC patients. The expression of STAT3 mRNA was further detected by in situ hybridization. The association of pSTAT3 and SOCS3 expression with clinicopathological factors and patient survival was analyzed. Altered expression of pSTAT3 and SOCS3 was observed in HCC specimens, compared to adjacent non-tumor tissue. Increased expression of pSTAT3 was correlated with large tumor size, higher clinical stage, Ki67 and VEGF expression, as well as poor patient survival. Decreased expression of SOCS3 was correlated with the expression of Ki67, VEGF and pSTAT3, and poor patient survival. Moreover, the expression of pSTAT3 was conversely correlated with SOCS3 expression in HCC. Our results indicate that deregulated expression of pSTAT3 and SOCS3 may play roles in the development and progression of HCC. PSTAT3 and SOCS3 should be further evaluated as potential novel biomarkers for HCC prognosis.