Each 10-unit increase in the 21-gene RS was associated with 28% (95% CI: 5–47%) higher risk of breast cancer recurrence; this association was also observed in patients with favorable metabolic profiles in relevant to an absence of obesity, insulin resistance, hyperglycemia, hypertension, or dyslipidemia (28–44% higher risk) and among women with a low level of insulin, C-peptide, or the IGF1/IGFBP3 ratio (41–155% higher risk). This evidence concerns the gene IGF1 and breast cancer.