INS and type 2 diabetes mellitus: Endogenous hyperinsulinemia, mainly observed in type 2 diabetes mellitus patients in response to reduced insulin sensitivity of peripheral tissues, may also contribute to the relationship between diabetes and cancer by activating insulin receptors, IGF-1 receptors and hybrid insulin/IGF-1 receptors, all of which can stimulate cancer cell proliferation and survival and promote metastasis, thus favoring cancer progression [24].