Breast cancer (BC) and Diabetes Mellitus (DM) are medical conditions that
are becoming more common in many developed nations. When compared with healthy
individuals, diabetic people have an elevated risk of BC and more fatalities from the
disease. This implies an association and that the two conditions share risk factors and
pathophysiological pathways. Although the causal processes beneath this connection
remain incompletely understood, plausible ties include hyperinsulinemia, insulin
resistance, oxidative stress, chronic inflammation, hyperglycaemia, and hormonal.
Each of these conditions has been proposed for fostering tumour progression in
numerous manners. Although hyperglycaemia is one of the most extensively
researched metabolic abnormalities in DM, the consequences of high blood sugar on
malignancy have garnered less scrutiny than the influence of insulin, insulin-like
growth factor-1 (IGF-1), oxidative stress, and chronic inflammation on the progression
of cancer. The purpose of this chapter is to provide insight into the link between
impaired glycaemic status and oxidative stress of DM with the causation, type,
progression, and mortality of BC. Several unexplored areas exist, and new hypotheses
may emerge in the days to come.
Keywords: Breast cancer, Diabetes mellitus, Glucose metabolism, Oxidative stress.