Triple-Negative Breast Cancer

The triple receptor-negative breast cancer (TNBC) subtype is characterized by the lack of expression of both hormone receptors as well as lack of over-expression and/or lack of gene amplification of human epidermal growth factor receptor 2 (HER2). Approximately 10–15% of breast carcinomas are known to be of the TNBC subtype, which constitutes approximately 80% of all ‘basal-like tumours’. Risk factors for TNBC include young age at breast cancer diagnosis, young age at menarche, high parity, lack of breast feeding, high body mass index and African American ethnicity. The majority of BRCA1 tumours are TNBC. TNBC has a worse prognosis and tends to relapse early compared with other subtypes of breast cancer. Conversely, it displays increased chemosensitivity compared with other breast tumour subtypes. Several agents are currently being investigated as potential therapeutic agents for the treatment of women with TNBC including agents targeted against EGFR, anti-angiogenic agents, multityrosine kinase inhibitors and poly (ADP-ribose) polymerase (PARP) inhibitors. This review focuses on the epidemiology of TNBC, its pathological features, natural history and recurrence patterns as well as current and future management options.