We further investigated the relationship between HER2 targeted therapy efficacy and IGF-1 level, interacted with obesity (Figure S2), and found that only in patients with BMI <24.0 kg/m2 and receiving adjuvant targeted therapy, those with higher expression of IGF-1 had a tendency of superior RFS than those with lower IGF-1 (Log-rank P = 0.053; Figure S2A). Here, ERBB2 is linked to obesity due to melanocortin 4 receptor deficiency.