Given the recent recommendations that optimal adjuvant hormonal therapy for a postmenopausal woman with HR+ early breast cancer should include an aromatase inhibitor (such as anastrozole) as initial therapy or after treatment with tamoxifen (Winer et al, 2005), such findings will clearly be of relevance to healthcare decision makers both in the United Kingdom and elsewhere. The gene discussed is CYP19A1; the disease is breast cancer.