A new study has suggested SET and MYND domain-containing protein 2 as a biomarker for poor prognosis of patients with hepatocellular carcinoma (HCC).
SET and MYND domain-containing protein2 (SMYD2), a histone lysine methyltransferases, is a candidate human oncogene in multiple tumours. Emerging evidence suggests that SMYD2 inhibits tumour suppressor proteins p53, Rb, and PTEN and enhances the poly (ADP-ribose) activity of the oncogenic protein PARP1 in cancer cells. Moreover, SMYD2 also plays promoting roles in the development and progression of various tumours. The mRNA and protein expression levels of SMYD2 have been reported to be overexpressed in bladder carcinoma, oesophageal squamous cell carcinoma, paediatric acute lymphoblastic leukaemia, gastric cancer and HPV-unrelated head and neck squamous cell carcinoma.
A study led by Dr. Shi-Kun Liu at the Central South University in China discovered that the SMYD2 expression in HCC tissues was significantly up-regulated at both mRNA and protein levels as compared with the matched adjacent non-tumorous tissues. By immunohistochemistry, positive expression of SMYD2 was examined in 122/163 of HCC and in 10/59 of tumour-adjacent tissues. Positive expression of SMYD2 was correlated with tumour size, vascular invasion, differentiation and TNM stage. In univariate survival analysis, a significant association between positive expression of SMYD2 and shortened patients’ survival was found. Importantly, SMYD2 expression together with vascular invasion provided significant independent prognostic parameters in multivariate analysis. Functionally, SMYD2 silenced markedly inhibited cell proliferation and cell cycle progression in SMMC-7721 cell.
The results from this study suggest that SMYD2 can serve as a promising biomarker for the early diagnosis and prognostic prediction of HCC patients, and can potentially act as an effective therapeutic target of HCC.