In looking for new ways to fight breast cancer, scientists from Duke-NUS Medical School have unmasked a surprising role of a protein generally associated with cancer growth. They have discovered that in estrogen receptor-positive (ER+) breast cancer, this protein acts as a tumor suppressor instead. ER+ breast cancer constitutes about 80 percent of all breast cancer diagnoses, yet nearly 50 percent of women diagnosed with it experience a relapse after initial treatment.