UCSF researchers identify gene involved in inhibiting breast tumor growth

Valerie Weaver and collaborators have identified the first positive regulator of BRCA1, establishing that the loss of the homeobox gene HoxA9 promotes tumor growth in breasts. The scientists found that restoring HoxA9 in breast cancer cells inhibited their malignant behavior in culture and in vivo. Intriguingly, the researchers learned that while HoxA9 has been shown to promote leukemia, it actually functions as a tumor suppressor in the breast. This eight-year project was led by Valerie M. Weaver, PhD, a faculty member in the Department of Surgery, "The finding demonstrates what we've seen before - that a gene that drives tumors in one disease can reduce tumors in another disease," she says.