Background: Peroxisome proliferator-activated receptor gamma (PPARG), a nuclear hormone receptor, plays a critical role in the lipid and glucose homeostasis, adipocyte differentiation, as well as intracellular insulin-signaling events. Several studies have been conducted to explore the associations of PPARG polymorphisms with breast cancer (BC), yet the findings are inconsistent.
Methods: Databases of Pubmed and Embase were searched until October 5, 2014. The association between PPARG polymorphisms and BC risk was determined by crude odds ratios (ORs) with their 95% confidence intervals (CIs).
Results: Finally, there are nine publications involving 3,931 BC cases and 5,382 controls included in this meta-analysis. No significant association was observed between PPARG rs1801282 C>G variants and overall BC risk in all genetic comparison models. However, in a subgroup analysis by ethnicity, significant association was observed between PPARG rs1801282 C>G variants and decreased BC risk in three genetic models: GG+CG vs. CC (OR, 0.83; 95% CI, 0.71-0.96; P = 0.011), CG vs. CC (OR, 0.82; 95% CI, 0.71-0.96; P = 0.011) and G vs. C (OR, 0.85; 95% CI, 0.75-0.97; P = 0.016) in Caucasians and in a subgroup analysis by menopausal status, significantly decreased BC risk was also found in two genetic models: GG+CG vs. CC (OR, 0.79; 95% CI, 0.67-0.95; P = 0.011) and CG vs. CC (OR, 0.77; 95% CI, 0.64-0.92; P = 0.005) in post-menopause subgroup. For PPARG rs3856806 C>T, we found no significant association between PPARG rs3856806 C>T polymorphism and breast cancer.
Conclusions: In summary, despite some limitations, the results suggest that PPARG rs1801282 C>G polymorphism may be a protective factor for BC in Caucasians and in post-menopause women.
Keywords: Breast cancer; meta-analysis; peroxisome proliferator-activated receptor gamma; polymorphism.