Karolinska Institute researchers in Sweden have found a protein that could aid doctors in determining what type of treatment patients with hormone driven breast cancer should undergo. Published in Nature Communications, this recent study shows that high levels of a protein known as retinoic acid receptor alpha (RARA) in breast tumors can be associated with an poor response to the cancer drug tamoxifen. The findings are based on a new proteomics technique, developed by the Science for Life Laboratory.