SMYD3 and breast cancer: There was a distinctive difference in allele frequency (χ2 =9.1, P=0.034) and genotype frequency (χ2 =39.971, P<0.001) of SMYD3 VNTR, and 3 allele could increase the susceptibility to breast cancer (OR =1.305, 95% CI: 1.097–1.552, P=0.003) (Table 4).