The difference of around 2.2 nmol/L in IGF-I concentrations between the highest and the lowest categories of dairy milk intake4,6 would suggest that the higher intake of dairy milk might increase breast cancer risk through IGF-I by around 5%,7 which is much smaller than the increase in risk observed in AHS-2; however, there are other growth factors and bovine sex hormones present in dairy products, and it is possible that these and/or other IGFs or their binding proteins also play a role, which might contribute to a larger association with breast cancer risk. Here, IGF1 is linked to breast cancer.