Analysis of individual MS criteria revealed significant associations with blood pressure (<i>p</i> = 0.028 and <i>p</i> = 0.022 for systolic and diastolic pressure, respectively) and fasting glucose changes (<i>p</i> = 0.008).<h4>Conclusions</h4>Plasma FGF21 may act as a biomarker for monitoring exercise-based interventions which reduce MSs, particularly hypertension and hyperglycemia, in AI-treated BC survivors. Here, FGF21 is linked to Hypertension.