INS and type 2 diabetes mellitus: Similarly, treatment of T2D patients with insulin or insulin secretagogues (e.g., sulfonylurea) is associated with significantly higher risk of breast cancer [8, 9], whereas retrospective clinical studies have indicated improved disease-free and overall survival of diabetic ErbB2 breast cancer patients treated with insulin sensitizers (metformin, thiazolidinediones) [10–13].