Leptin as a risk factor for the development of colorectal cancer

Obesity has been associated with many types of cancer, including colorectal cancer (CRC). The mechanisms by which obesity increases the risk for development of CRC can be explained by factors such as hyperinsulinemia, increases in proinflammatory cytokines, estrogens and insulin-like growth factors (IGFs), and alterations in adipokines levels. Leptin is the most abundant adipokine, and has also been associated with an increased risk for development of CRC, as demonstrated by innumerous in vitro and in vivo experiments, and by large epidemiological studies. By binding to its receptor, leptin activates several intracellular cascades, stimulating cell growth and proliferation, inhibiting apoptosis, and promoting angioneogenesis. Leptin has also proinflammatory effects that promote a low-grade inflammatory state and contribute to the development of CRC. A better understanding of the associations between leptin and CRC might lead to the development of novel approaches for the diagnosis, risk stratification, and treatment of CRC.