TNF and obesity due to melanocortin 4 receptor deficiency: The results showed that the initiation and development of breast cancer were promoted by obesity in the models and that the expression was increased of several genes related to proliferation, including TNFa, VEGF, IKKβ, and mTOR, indicating that TNFα may activate the IKKβ/mTOR/VEGF signaling pathway in the tumors of obese mice (Figure 1).