Histone Deacetylase Inhibitors as a Potential Future Therapy for Breast Cancer Brain Metastasis

Breast cancer (BC) stands as the most diagnosed malignancy among women, significantly impacting global health.1, 2 In 2018, it was estimated that approximately 2.1 million women were diagnosed with BC, leading to over 600,000 deaths. Alarmingly, the global incidence of this disease has been rising at an annual rate of 3.1%.2

BC’s complexity is further unravelled when categorised into five distinct subtypes. These classifications are based on the presence or absence of certain biomarkers: the oestrogen receptor, progesterone receptor, HER2, and Ki67. These subtypes include luminal A, luminal B, luminal B-like, HER2-positive, and triple-negative BC.3 The incidence and mortality rates vary significantly across these subtypes, with HER2-positive cases associated with the highest risk of death. This elevated risk is largely due to the increased likelihood of developing brain metastases.1, 3