LEP and obesity due to melanocortin 4 receptor deficiency: Together, the altered hormonal and inflammatory milieu of obesity may contribute significantly to cancer growth and progression via promoting mitogenesis (e.g., leptin, IGF-1, insulin), angiogenesis (e.g., VEGF, IL6, IL8), and invasion (e.g., leptin, IL6, PAI-1, CCL5, CCL2) [19].