Triple-Negative Breast Cancer: Understanding Why Some Patients Respond to Immunotherapy

An international study conducted in collaboration with Institut Jules Bordet (H.U.B) provides new insights into the response to immunotherapy in triple-negative breast cancer.

In advanced triple-negative breast cancer, immunotherapy can be given in combination with chemotherapy. However, not all patients respond to treatment in the same way, and researchers are working to understand why.

Published in the prestigious scientific journal Cell Reports Medicine, this new study draws in particular on tumour samples collected as part of SYNERGY, an international clinical trial coordinated by Institut Jules Bordet. These samples enabled researchers to conduct an in-depth analysis of the characteristics of the tumours and the environment surrounding them.

The study was conducted as part of IMMUCAN, a European consortium bringing together researchers and specialised centres to better understand the mechanisms underlying response and resistance to cancer treatments. The researchers combined several technologies to study both the characteristics and activity of tumour cells, as well as the cells surrounding them.

The researchers found that the behaviour of a tumour does not depend solely on the cancer cells themselves. The surrounding environment also plays an important role. Some tumours are surrounded by an environment that appears to support the activity of the immune system. Others, on the contrary, develop an environment that may help the tumour resist treatment.

The study also provides new insights into what happens inside the tumour during treatment. By comparing samples collected before treatment and after two weeks of treatment, the researchers observed changes in the tumour environment. In patients whose disease progressed less favourably, certain immune cells, particularly macrophages, became more numerous.

“These findings highlight the importance of looking not only at the tumour cell itself, but also at its entire surrounding environment,” explains oncologist Elisa Agostinetto, researcher at Institut Jules Bordet and co-author of the study. “A better understanding of these interactions could ultimately help us identify which patients are most likely to benefit from immunotherapy and develop new strategies to overcome resistance mechanisms.”

This study also highlights the value of international collaboration in academic research. By bringing together researchers, clinicians and complementary areas of expertise through initiatives such as IMMUCAN, with the support of organisations such as EORTC (European Organisation for Research and Treatment of Cancer), which coordinates and supports international clinical cancer research, and BIG (Breast International Group), an international network dedicated to clinical breast cancer research, it becomes possible to make in-depth use of samples collected through clinical studies and compare findings across different patient groups.

It also underlines the importance of European funding, which is essential to enabling these international collaborations and this type of academic research to develop.

Ultimately, this work could contribute to more personalised treatment strategies for triple-negative breast cancer and help identify new therapeutic approaches.