Purpose: To investigate the associations of four commonly studied single nucleotide polymorphisms (SNP) of the vascular endothelial growth factor (VEGF), including -460T/C (rs833061), - 634G/C (rs2010963), - 2578C/A (rs699947), and +936T/C (rs3025039), with the incidence, aggressiveness, and tumor markers expression of breast cancer in the Northern China Han population.
Methods: Followed the genomic DNA extraction, a total of 259 patients with breast cancer (case group) and 273 healthy women (control group) underwent genotyping by PCR-LDR SNP assays. The associations between VEGF gene polymorphisms and the incidence, aggressiveness, and tumor markers expression of breast cancer were analyzed.
Results: Significant differences were observed in allele frequency and genotype distribution of - 634G/C between breast cancer cases and healthy controls (p = 0.006, 0.013). Individuals who carry the G allele more likely had a lower risk of breast cancer (OR, 0.866, 95% CI 0.782-0.959). Compared with CC genotype carriers, women who had the CG and GG genotypes demonstrated a relatively lower risk (OR, 0.860, 95% CI 0.757-0.978, p = 0.022; OR, 0.778, 95% CI, 0.656-0.924, p = 0.004, respectively). When we stratified the group of patients according to the status of tumor markers, a significant association of - 634G/C SNP and Ki-67 expression was observed. The CC genotype carriers were more likely to be characterized by high expression of Ki-67 (p = 0.031). Further analysis showed that the - 460T/-634C/-2578C/+936C haplotype was more associated with a higher risk of breast cancer (OR, 1.445, 95% CI 1.123-1.859, p = 0.004), whereas the - 460T/- 634G/- 2578C/+936C one was associated with a lower risk (OR, 0.736, 95% CI 0.563-0.963, p = 0.025).
Conclusions: In the present study, we concluded that VEGF gene - 634G/C polymorphism is related to the incidence of breast cancer in the Han population in Northern China and also might be associated with tumor proliferation index Ki-67.
Keywords: Breast cancer; Ki-67; Single nucleotide polymorphism; Vascular endothelial growth factor.