Figure 2.

Recruitment of inflammatory cells in the tumor microenvironment mediated by obesity. (a) Obese adipose tissue is characterized by hypertrophy and hyperplasia of adipocytes, apoptosis and a shift in the stroma from less inflammatory eosinophils and M2-polarized cells (promoting insulin sensitivity), to an environment rich in pro-inflammatory M1-polarized macrophages, crown-like structures and activated fibroblasts. The mammary gland displays many of the same phenotypic changes with obesity. This low-level chronic inflammation in the tissue is known to induce oncogenesis, with an interesting shift in polarized macrophages from less M1 tumoricidal macrophages to more M2 tumor-promoting macrophages (b).