Overexpression of SMYD3 Is Predictive of Unfavorable Prognosis in Hepatocellular Carcinoma.

SET and MYND domain-containing protein 3 (SMYD3) is a kind of histone lysine methyltransferase, responsible for transcriptional activation as a member of an RNA polymerase complex. The ectopic expression of SMYD3 is proved to promote the progress of many kinds of cancers. In hepatocellular carcinoma (HCC), SMYD3 was demonstrated to promote the proliferation and metastasis of HCC cell lines, but the clinical significance of SMYD3 has not been elucidated. In the present study, we detected the expression of SMYD3 in 100 HCC tissues with immunohistochemistry and divided these tissue specimens into high-expression group and low-expression group according to the immunohistochemical score of SMYD3. Importantly, the intensity of SMYD3 immunoreactivity was significantly stronger in HCC tissues than that in adjacent normal tissues. Moreover, high expression levels of SMYD3 were significantly associated with larger tumor size (P = 0.043), suggesting that SMYD3 could promote the proliferation of HCC. Moreover, patients with positive hepatitis B virus infection had higher expression levels of SMYD3 (P = 0.013). With univariate and multivariate analysis, we explored the prognostic significance of SMYD3 in HCC. As a result, high expression levels of SMYD3 were significantly correlated to the poorer clinical outcome of HCC patients (P = 0.009) and were identified as an independent risk factor of HCC for predicting the unfavorable prognosis. In conclusion, overexpression of SMYD3 is an independent prognostic risk of unfavorable prognosis of HCC. We propose that the anti-SMYD3 therapy may be a potential approach to treat HCC.