Establishing the Role of PPARβ/δ in Carcinogenesis.

The role of the nuclear hormone receptor peroxisome proliferator-activated receptor β/δ (PPARβ/δ) in carcinogenesis is controversial because conflicting studies indicate that it both inhibits and promotes tumorigenesis. In this review, we focus on recent studies on PPARβ/δ including the significance of increased or decreased PPARβ/δ expression in cancers; a range of opposing mechanisms describing how PPARβ/δ agonists, antagonists, and inverse agonists regulate tumorigenesis and/or whether there may be cell context-specific mechanisms; and whether activating or inhibiting PPARβ/δ is feasible for cancer chemoprevention and/or therapy. Research questions that need to be addressed are highlighted to establish whether PPARβ/δ can be effectively targeted for cancer chemoprevention.