The annals of the recalcitrant triple negative breast cancer: Classifications and its potential ameliorative measures

Breast cancer is a heterogeneous disease that can be classified into different clinical, histopathological and molecular subtypes.‘Triple-negative’ breast cancer (TNBC) comprises about 15% of all breast cancer cases and are devoid of the estrogen receptor (ER), progesterone receptor (PR) and the human epidermal growth factor receptor 2 (HER2) is overexpressed. Triple Negative Breast cancer is differentiated by Brenton et al 2005 on the basis of prognosis and response to the therapy. The treatment that was possible till date for TNBC was chemotherapy as these can breast cancer cells typically lack ER, PR and express ex HER2 Hence the patients are unable to receive any conventional endocrine therapies .It is quite intriguing for for scientific and translational researcher, as TN phenotype initially appears as a potential surrogate for basal-like breast cancers. ER and HER2 mRNA expression are found in basal/ myoepithelial cells of the normal breast, but one of the ‘intrinsic gene’ subtypes of the disease TNBC is characterized by the lack of these ER and HER2 mRNA expression. According, to Perou et al 2000 TNBC are lacking ER and PR expression and HER2 over-expression /HER2 gene amplification.

TNBCs usually exhibit quite high belligerent behaviour and is predominantly found in young women of Hispanic and African descent and a considerable link with BRCA1 germline mutations has also been detected. These TNBCs exhibit quite high metastasis which culminates in the death of the patient within 5 years after diagnosis. However, TNBC is vastly heterogeneous and best considered as an umbrella term which comprises of different entities with characteristic genetic, histological,transcriptional, and clinical attributes. Till date, no effective treatment for metastatic TNBC is available following surgery, radiation and chemotherapy