EZH2 and SMYD3 expression in papillary thyroid cancer

Recent studies have revealed the significant role of SMYD3 and EZH2 genes in the development and aggressiveness of numerous types of malignant tumor. Therefore, the present study aimed to investigate the expression of SMYD3 and EZH2 in papillary thyroid cancer, and to determine the correlation between the expression of these genes and clinical characteristics. Resected thyroid tissue samples from 62 patients with papillary thyroid cancer were investigated. Thyroid tissue derived from the healthy regions of removed nodular goiters from 30 patients served as the control group. Reverse transcription-quantitative PCR analysis was employed to detect relative mRNA expression levels. Primer sequences and TaqMan(®) hydrolysis probe positions for EZH2 and SMYD3 were determined using the Roche Universal ProbeLibrary Assay Design Center version 2.50. EZH2 expression was detected in all thyroid cancer samples and in 83.3% of benign lesions. Notably, EZH2 was revealed to be upregulated in thyroid cancer tissues compared with control tissues (P=0.0002). EZH2 expression was positively correlated with tumor stage (P<0.0001; r=0.504), and multiple comparison analysis revealed that the highest expression of EZH2 was detected in samples staged pT4 (P=0.0001). SMYD3 expression was detected in all thyroid cancer samples and in 96.7% of healthy thyroid tissues; notably, the expression levels were similar in both groups. In addition, there was no correlation between SMYD3 expression and the aggressiveness of papillary thyroid cancer. In conclusion, overexpression of the EZH2 gene may be associated with the development of papillary thyroid cancer and EZH2 may be a potential therapeutic target in papillary thyroid cancer.