IMIM (Hospital del Mar Medical Research Institute) Dec 4 2025 A study led by researchers at the Hospital del Mar Research Institute advances one of the most significant milestones in breast cancer treatment, making immunotherapy effective against the most common tumor type, estrogen receptor-positive or luminal breast cancer. This subtype accounts for 70% of breast cancer cases, and despite effective treatments, it causes the highest mortality in total cases. Additionally, immunotherapy is not