Optimizations are expected in the development of immunotherapy for the treatment of Triple-negative breast cancer (TNBC). We studied the expression of galectin-9 (Gal-9) after irradiation and assessed the differential impacts of its targeting with or without radiotherapy. Tumor resections from TNBC patients who received neoadjuvant radiotherapy revealed higher levels of Gal-9 in comparison to their baseline level, only in non-responder patients. Gal-9 expression was also found to be increased in TNBC tumor biopsies and cell lines after irradiation. We investigated the therapeutic advantage of targeting Gal-9 after radiotherapy in mice. Irradiated 4T1 cells or control non-irradiated 4T1 cells were injected into BALB/c mice. Anti-Gal-9 antibody treatment decreased tumor progression only in mice injected with irradiated 4T1 cells. This proof-of-concept study demonstrates that Gal-9 could be considered as a dynamic biomarker after radiotherapy for TNBC and suggests that Gal-9 induced-overexpression could represent an opportunity to develop new therapeutic strategies for TNBC patients.
Keywords: galectin‐9; molecular targeted therapy; radiotherapy; triple‐negative breast cancer.
© 2024 The Author(s). International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.