TNF and obesity due to melanocortin 4 receptor deficiency: In general, serum levels of markers associated with obesity, such as insulin, IGF-1, IL-6, TNF-α, leptin, and adiponectin, may trigger the PI-3K/Akt signaling pathway to promote cell growth and colon cancer carcinogenesis; conversely, the adiponectin-mediated inhibition of PI-3K/Akt signaling pathway, through the suppression of TNF-α and IL-6, is able to regulate cell growth inhibition (Figure 1) [126].