CYP19A1 and breast cancer: The clinical predictive validity of the Oncotype DX assay was evaluated in a large group of postmenopausal women with HR-positive breast cancer that were treated with adjuvant aromatase inhibitors: for patients with node-negative disease, the recurrence rates were 4%, 12%, and 25% for patients with a low, intermediate, and high RS, respectively; for node-positive disease, the recurrence rates were 17%, 28%, and 49% for patients with a low, intermediate, and high RS, respectively [67].