Figure 2.

Adipose-related factors engaged to the initiation and progression of breast cancer. Normal adipose tissue, generally existing in “normal weight” (NW) subjects (%BF cutoff values between 8 and 20% for men and 14 and 23% for women), is characterized by smaller and less adipocyte cells and M2-polarized macrophages that release anti-inflammatory cytokines and adiponectin that contribute to normal breast cell development. In overweight (OW) and obese condition (OB), adipose tissue is characterized by larger size and more abundant adipocytes, releasing pro-inflammatory cytokines, M1-polarized macrophages, leptin, free fatty acids (FFAs), and estrogens, synthesized by aromatase enzyme. These factors act as mutagens stimulating the growth of tumor cells. A tumor environment produces more reactive oxygen species (ROS), which generate DNA damage, amplify and induce mutagenesis, tumor growth and progression. Therefore, the OW/OB condition provides a favorable microenvironment for adipose tissue to induce tumor establishment and progression.