The promoter DNA methylation of peroxisome proliferator-activated receptor γ1 was increased by inflammatory cytokine such as TNFα and reduced by TH2 cytokine such as IL-2, which led to the activated M1 and M2 macrophages in adipose tissue, and the aggravated and alleviated insulin resistance in obesity [20]. This evidence concerns the gene TNF and obesity due to melanocortin 4 receptor deficiency.