STAT3 and breast cancer: Hyperglycaemia induces oxidative stress through direct or indirect pathways in BC cells by increasing levels of insulin/IGF-1 and inflammatory cytokines, particularly IL-6 and TNF-α.55 Together, they activate nuclear factor kappa (NFκB), signal transducer activator of transcription 3 (STAT3) and the hypoxia-inducible factor 1-alpha (HIF1α).56 These factors result in increased free radical production, leading to damage to DNA, lipids and further amplification of the inflammatory processes [27].