Conversely, the modern era of systemic therapy for breast cancer includes the use of taxane-based chemotherapy regimens as well as the utilization of traztuzumab and pertuzumab for HER2 + tumors, longer (10-year) courses of tamoxifen for patients with hormone-sensitive tumors, as well as the use of aromatase inhibitors and combination therapy, all of which have likely contributed to lower recurrence rates in the current era. The gene discussed is CYP19A1; the disease is breast cancer.