Obesity and cancer: local and systemic mechanisms.

Obesity is a leading modifiable risk factor for the development of several epithelial malignancies. In addition to increasing risk, obesity also confers worse prognosis for many cancers. Obesity represents an overall state of energy imbalance frequently associated with systemic effects including insulin resistance, altered hormone signaling, and high circulating levels of proinflammatory mediators. In addition to its systemic effects, obesity causes subclinical white adipose inflammation including increased tissue levels of proinflammatory mediators. Both local and systemic effects are likely to contribute to the development and progression of cancer. An understanding of the interplay between local and systemic alterations involved in the obesity-cancer link provides the basis for developing interventions aimed at mitigating the protumorigenic effects.