Correlated expression of peroxisome proliferator-activated receptor γ with high histologic grade and basal type in invasive ductal carcinoma of the breast

Backgroud and aim: Peroxisome proliferator-activated receptor γ (PPARγ) is one of the ligand-activated transcription factors belonging to the nuclear hormone receptor family. The protein is expressed in various kinds of tumor and has been implicated as a tumor suppressor in most cancers. We aimed to understand the role of PPARγ in breast cancer. Methods: The expression of PPARγ in 288 cases of invasive ductal carcinoma was examined using tissue microarray and immunohistochemistry. Results: PPARγ immunoreactivity was detected in 21.5% of cases and significantly associated with expression of EGFR and ki-67 (P= 0.008; P= 0.046). PPARγ expression was correlated with high histological grade and basal type (P≤ 0.001; P= 0.009). Conclusions: PPARγ expression is related to poor prognostic factors of breast cancer. It is considered that PPARγ has evident tumor promoting properties in vivo, but receptor-independent effects of PPARγ ligands may compound its biologic effects in cancer. A better understanding of action mechanisms of the activated PPARγ is required.