INS and obesity due to melanocortin 4 receptor deficiency: The inconsistencies exist at the level: (1) of population data for incident disease risk; (2) of clinical data on the characteristics of the disease at diagnosis and on disease prognosis and outcomes; and (3) of the four mechanisms broadly cited to explain the obesity-breast cancer linkage, i.e., (a) sex hormone metabolism; (b) deregulated insulin signaling; (c) chronic low grade inflammation; and (d) altered adipokine expression.