Chen H, et al. - By analyzing 4,557 breast cancer cases, researchers assessed the influence of type 2 diabetes and diabetes medications on the risk of various breast cancer molecular subtypes (estrogen receptor [ER]+/human epidermal growth factor receptor-2 [HER2]-, ER+/HER2+, triple negative [TN, ER-/PR[progesterone receptor]-/HER2-] and HER2-overexpressing [H2E, ER-/PR-/HER2+]) in this retrospective multicenter population-based case-case investigation. Using polytomous logistic regression, they estimated odds ratios and corresponding 95% confidence intervals for each subtype by considering ER+/HER2- cases as the reference group. Among women with type 2 diabetes, odds of having a TN are greater rather than ER+/HER2- breast cancer; such greater odds were especially found among those who were users of metformin. Some preclinical data also supported these findings, indicating a possibly even stronger association of diabetes with the risk of TN disease.