Obesity is a risk factor for breast cancer in older women. A number of adipose-derived and obesity-related factors have been shown to affect tumour cell growth. These include adipokines, insulin, IGF-1 and oestrogens. The majority of obesity-related postmenopausal breast cancers are oestrogen-dependent. Since the ovaries no longer produce oestrogens after menopause, and that circulating levels are negligible, it is evident that it is the oestrogens produced locally within the breast adipose that are responsible for the increased growth of breast cancer cells. Aromatase is the enzyme that...