Moderate aromatase expression rendered ZR-75-1 cells tumorigenic without estrogen supplementation.

<p><b>A.</b> Luc-GFP expressing ZR-75-1/Aro Cl.10 and TT1 cells (2x10⁶) were inoculated into the inguinal mammary fat pads of 5-wk-old female nude mice. The tumor sizes were measured with a caliper in two dimensions. Tumor volumes were calculated with the equation V = (LxW²)/2, where L is length and W is width of a tumor. Values are mean±SEM of 10 tumors in 5 mice. B. The representative images (fluorescence on the left and bioluminescence on the right) C. The mice with growing tumors were divided into two groups and treated with vehicle or letrozole at 10 μg/mouse/day.