SHBG and obesity due to melanocortin 4 receptor deficiency: Growing scientific evidence shows obesity-related conditions such as insulin resistance, type 2 diabetes [50,51], and the metabolic syndrome [52] as well as obesity-related systemic markers (e.g., leptin [53], adiponectin [54], SHBG [55], insulin and the IGF axis [56,57,58,59,60] and C-reactive protein [61,62]) are associated with breast cancer.