Immunotherapy for Breast Cancer

Breast cancer is a heterogeneous disease with diverse molecular subtypes—HR+/HER2−, HER2+, and triple-negative breast cancer (TNBC)—each exhibiting distinct prognoses and treatment responses. Once considered immunologically "cold" and unresponsive to immunotherapy, breast cancer has emerged as a candidate for immune-based treatments, particularly in TNBC, where pembrolizumab combined with chemotherapy has demonstrated clinical efficacy in both neoadjuvant and advanced settings. This advancement marks a pivotal shift in the therapeutic landscape, prompting ongoing research into combination strategies involving immune checkpoint inhibitors and chemotherapy. Despite progress, breast cancer remains a leading cause of cancer-related mortality, with rising incidence among younger women, underscoring the need for innovative therapies. Biomarkers such as PD-L1 Combined Positive Score, tumor mutation burden (TMB), and tumor-infiltrating lymphocytes (TILs) are being actively investigated to guide patient selection and optimize immunotherapy outcomes, highlighting the importance of precision medicine in advancing treatment paradigms across all breast cancer subtypes.