A study published in the journal Nature Cancer, carried out within the Cancer Program at the Hospital del Mar Medical Research Institute (IMIM-Hospital del Mar) by the Cancer Stem Cells and Metastasis Dynamics Laboratory, led by Dr. Toni Celià-Terrassa, and the Laboratory of Molecular Cancer Therapy, coordinated by Dr. Joan Albanell, with the participation of international centers, has discovered an approach that radically increases the success of immunotherapy in one of the most aggressive types of tumors, triple-negative breast cancer. This subtype, although accounting for only 15% of cases, is one of the most rapidly progressing and affects younger patients. In this work, researchers found that tumor stem cells are the main cause of immunotherapy resistance in this subtype of breast cancer. The reason is that these cells are invisible to the immune system, making immunotherapy ineffective. In addition, the study offers a promising solution to this situation by using a new therapeutic approach in preclinical models that makes cancer stem cells visible to the immune system so that it can then eliminate the tumor.