Breast cancer can be subdivided in different subtypes, with the hormone-receptor positive (HR+) breast cancer being the most abundant, accounting for 70% of the cases. The interaction between these HR+ tumours and the immune system is not well understood.
In this study, researchers from the CAMS Oxford Institute in NDM and the Translational Immune Discovery Unit in the MRC Weatherall Institute of Molecular Medicine investigated whether patients with HR+ breast cancer have immune cells, specifically CD8 T cells, that can recognise and attack their tumours.
By using a method that exposes immune cells to tumour material in the lab, they found that many patients, especially those with early-stage disease, do have tumour-reactive CD8 T cells. However, in patients whose cancer had spread to the lymph nodes, these tumour-fighting T cells were much less common. This suggests that the ability of immune cells to recognise the tumour may be reduced in more advanced disease.
These findings offer new hope for improving immunotherapy in breast cancer. By harnessing the strong immune responses seen in early-stage patients, scientists may be able to develop new treatments for those with more advanced disease.
Tao Dong, Co-Director of the CAMS Oxford Institute, said: ‘The effective antitumoral response identified in our study at the early stage of HR+ breast cancer tissue not only suggests that those T cells could be harnessed to develop immunotherapeutic approaches for late-stage HR+ patients, but also establishes an effective research pipeline in identification and isolation of tumour-reactive T cells from patients’ blood and tissue samples. This is critical for us to study the key beneficial factors affecting cancer specific T cell responses which in turn could be used as potential targets for immune therapy.’
Mariana Pereira Pinho, first author on the study, said: ‘We found that people with more advanced hormone-positive breast cancer have a weaker immune response against their tumours. This may help explain why standard immunotherapy doesn't work as well for them—but it also opens the door to trying new kinds of treatment.’
If you’d like to find out more about the study, read the full paper on the Cell Reports Medicine website: https://www.cell.com/cell-reports-medicine/fulltext/S2666-3791(25)00325-8