Fig. 1.

Various pathways may explain the mechanism by which obesity induces carcinogenesis and exacerbates cancer progression. Obesity increases adipocytes, and the extent of systemic inflammation, and oxidative stress. Insulin resistance induced by obesity results in increased serum insulin levels, augmented IGF-1 signaling, increases serum leptin levels and suppresses serum adiponectin levels. Increases in insulin resistance, IGF-1 signaling, oxidative stress, free fatty acid (FFA), inflammatory signaling, and changes in adiopkines and other macromolecules, may contribute to cancer progression, and metastasis