Abstract
Diabetes and obesity are linked to a higher risk of breast and other cancers.
In addition to the direct effects of hyperglycaemia and insulin resistance on breast
cancer cells, the complications of diabetes, obesity, and metabolic syndrome are
characterised by a dysfunctional endothelium and increased inflammation in tissue
phenomena that are intimately related and occur concurrently in breast cancer
progression. However, the complexity of the underlying mechanisms, together with the
interplay of diet and physical activity contributing to energy balance and the role of
adipose tissue, hyperglycaemia, insulin resistance, and glucose intolerance, pose
challenges to our understanding of the basis of this increased risk. In addition to being
an established risk factor for postmenopausal breast cancer, abdominal obesity, also
known as central obesity, may also raise the chance of triple-negative breast cancer,
which is more common in premenopausal women. This chapter explains how various
parameters like oestrogen, mammography, density, adipokines, insulin-signalling
pathway activation, and inflammatory conditions, may play a part in this seemingly
contradictory association. A key focus of this chapter is to better understand the impact
of obesity and diabetes in the pathogenesis of breast cancer and, hence, provide some
clarity into the interrelationships involved in between.