Vascular function has been studied in several cohorts of cancer patients and includes prior work from our group in breast cancer patients.19 These patients, however, underwent aromatase inhibitor therapy only; those with chemotherapy or HER-2-directed therapy were excluded.19 The current study henceforth complements this prior study and, using the same definition for RHI change, it likewise shows a greater proportion of patients with a decline in RHI in patients after AC treatment. Here, CYP19A1 is linked to breast carcinoma.