Additionally, the inflammatory state of mammary glands from Sfrp1−/− mice fed a HFD is elevated as revealed by increased macrophage infiltration and pro-inflammatory cytokine expression [6] Considering the connection between obesity and inflammation, loss of Sfrp1 may be a critical early event in obesity associated breast cancer initiation. This evidence concerns the gene SFRP1 and obesity due to melanocortin 4 receptor deficiency.