INS and breast cancer: However, despite adiposity and insulin resistance having both been linked to an increased risk of postmenopausal breast cancer, whether women with high body fatness who have normal insulin sensitivity [a low level of homeostasis model assessment of insulin resistance (HOMA‐IR) or circulating insulin or C‐peptide levels], or those with normal body fatness who have elevated levels of insulin are at risk of breast cancer is not well‐documented.