SET and MYND Domain-Containing Protein 3 (SMYD3) Polymorphism as a Risk Factor for Susceptibility and Poor Prognosis in Ovarian Cancer

BACKGROUND We investigated the relationship of the polymorphisms of SET and MYND domain-containing protein 3 (SMYD3) with risk and prognosis of ovarian cancer. MATERIAL AND METHODS The polymerase chain reaction (PCR) amplification method was applied to detect the polymorphisms of variable number of tandem repeats (VNTR) in the SMYD3 gene promoter region for 156 patients with ovarian cancer (case group) and 174 healthy people (control group). Quantitative reverse transcription polymerase chain reaction and Western blot were applied to detect SMYD3 mRNA and protein expressions. RESULTS The frequencies of VNTR genotype 3/3 and allele genotype 3 in the case group were significantly higher than those in the control group, while the frequency of genotype 2/2 in the control group was significantly higher than that in case group (all P<0.05). The proportion of poorly differentiated patients carrying VNTR genotype 3/3 was significantly higher than the proportion of poorly differentiated patients carrying VNTR genotype 2/2+2/3, while the proportion of patients carrying genotype 3/3 with International Federation of Gynecology and Obstetrics (FIGO) stage III-IV disease was significantly higher than the proportion of patients carrying genotype 2/2 +2/3 with FIGO stage III-IV disease (all P<0.05). SMYD3 mRNA and protein expressions were higher in the patients carrying genotype 3/3 than they were in the patients with the 2/2+2/3 genotype (all P<0.05). The 5-year survival rate for patients carrying VNTR genotype 3/3 was significantly lower than that of patients carrying genotype 2/2+2/3, and Cox regression analysis showed that VNTR genotype 3/3 was an independent risk factor for ovarian cancer prognosis (all P<0.05). CONCLUSIONS VNTR genotype 3/3 of the SMYD3 gene was associated with the risk of ovarian cancer. The polymorphism of VNTR genotype could be recognized as an indicator for the poor prognosis of patients with ovarian cancer.