A retrospective study (17), including 4,557 cases, showed that women diagnosed with type 2 DM have a higher risk of TNBC (OR = 1.38, 95% CI 1.01-1.89) or human epidermal growth factor receptor 2 (HER2)-overexpressing breast cancer (OR = 1.38, 95% CI 0.93-2.06) than patients without a history of diabetes. Here, ERBB2 is linked to breast cancer.