Peroxisome proliferator-activated receptor gamma (PPARG) polymorphisms and breast cancer susceptibility: a meta-analysis.

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.