Elevated Levels of SET and MYND Domain-Containing Protein 3 Are Correlated with Overexpression of Transforming Growth Factor-β1 in Gastric Cancer.

Abstract

The aim of this study was to investigate the messenger RNA and protein expressions of SET and MYND domain-containing protein 3 (SMYD3) and transforming growth factor-β1 (TGF-β1) in gastric cancer (GC) and to explore the correlations between these proteins and the biologic behavior of GC. Expressions of SMYD3 and TGF-β1 were detected by real-time quantitative reverse transcription polymerase chain reaction and Western blot in GC tissues and adjacent nontumor tissues. In addition, SMYD3 and TGF-β1 expressions were analyzed by immunohistochemistry in formalin-fixed samples from 166 GC patients. The messenger RNA and protein expression levels of SMYD3 and TGF-β1 in GC tissues were significantly higher than those in adjacent nontumor tissues. A significantly positive correlation was found between SMYD3 expression and TGF-β1 expression in GC tissues. In addition, the size of the primary tumor and lymph node metastasis were identified as the independently relative factors of SMYD3 expression in GC tissues, and lymph node metastasis was identified as the independently relative factor of TGF-β1 expression. Multivariate analysis demonstrated that the degree of differentiation, serosal invasion, lymph node metastasis, SMYD3 expression, and TGF-β1 expression were the independent prognostic indicators for GC. Transforming growth factor-β1 expression was one of the optimal prognostic predictors of patients identified using the Cox regression with Akaike Information Criterion value calculation. SET and MYND domain-containing protein 3 expression and TGF-β1 expression in GC tissues were significantly and positively correlated. High expression levels of SMYD3 and TGF-β1 can indicate poor prognoses for GC patients.