High dietary lycopene intake was shown to suppress CS/NNK-induced emphysema in vivo by reducing mRNA expression of ATP-binding cassette transporter G1 (ABCG1), liver X receptor-α (LXRα) and peroxisome proliferator-activated receptor α (PPARα) involved in reverse cholesterol transport, which is the main driver of persistent and excessive inflammation after CS exposure [79]. Here, PPARA is linked to Cowden syndrome 1.