Previous epidemiological studies indicated that insulin promotes higher rates of some cancer types presentation in patients with type 2 diabetes mellitus (T2DM), such as colorectal cancer [47, 48], lung cancer [49], breast cancer [50], pancreatic cancer [10, 51], liver cancer [52–54], bladder cancer [55] and neuroendocrine tumors [55]. This evidence concerns the gene INS and breast cancer.