Additionally, immunotherapy is not effective or approved because it shows no immune system response in these tumors, except in a minority subgroup that, precisely, has low estrogen receptor levels. The work is published in the Journal of Clinical Investigation and led by Dr. Toni Celià-Terrassa’s team from the Cancer Stem Cells and Metastasis Dynamics Laboratory at the Hospital del Mar Research Institute. The study is supported by Ausonia through the Spanish Association Against Cancer.

How estrogen receptors affect immunity

The study highlights the importance of the estrogen receptor in the tumor’s strategy to evade immune system action. By analyzing public data from various clinical trials, the researchers found that this factor limits immune system infiltration and prevents immunotherapy from being effective. In contrast, inhibiting the estrogen receptor allows the activation of LCOR and interferon signals, both factors related to antigen presentation mechanisms on the cell surface, making the tumor cell visible to the immune system.