IbrahimAbdullahAlBalawi MDFRCSI, TahirAhmadMir BDS.
2017 International Journal of Advanced Research  
Breast cancers that demonstrate the absence of estrogen receptor and progesterone receptor and no overexpression of human epidermal growth factor receptor 2 (HER2) are referred to as triple-negative breast cancer (TNBC). Globally 1 million cases of breast cancer are diagnosed annually and Triple-negative breast cancer comprises 15%-20% of all breast cancers. The last decade has seen a revolution in the understanding of breast cancer, with new classifications proposed that have significant
more » ... stic value and provide guides to treatment options. There are many biomarkers in TNBC used for its subclassification. Clinically-practical assay/biomarkers that can reliably identify TNBC are necessary. Biomarkers may be useful as prognostic or predictive indicators as well as suggest possible targets for novel therapies. Copy Right, IJAR, 2017,. All rights reserved. ...................................................................................................................... Introduction:- Triple-negative breast cancers (TNBCs) are defined by the absence of estrogen and progesterone receptors and the absence of HER2 overexpression. These cancers represent a heterogeneous breast cancer subtype with a poor prognosis. In 2012 about 1.7 million women worldwide were diagnosed with breast cancer (BC), and 521,900 women died from it.(1-2) TNBC represents 10%-20% of invasive breast cancers and has been associated with African-American American race, deprivation status, younger age at diagnosis, more advanced disease stage, higher grade, high mitotic indices, family history of breast cancer and BRCA1mutations. TNBC is regularly reported to be three times more common in women of African descent and in pre-menopausal women, and carries a poorer prognosis than other forms of breast cancer. (3) These statistics include all subtypes of BC, but it is well known that BC is not a homogeneous disease. Tumors in the breast have long been classified according to their morphologic features, histologic type, and grade (severity). Four major intrinsic subtypes have been identified by genomic studies: the luminal subtypes A and B, which express hormone receptor-related genes, basal-like (BL) BC, and HER2-positive BC. (4) More recently, gene expression analysis using DNA microarray technology has identified additional breast tumor subtypes that were not apparent using traditional histopathologic methods. Based on gene expression profiles, breast cancer can be classified into 5 main groups Luminal A , Luminal B ,Basal-like ,HER2 ,Normal breast-like. (5-6) Most breast cancers originate from the inner ("luminal") cells that line the mammary ducts. Luminal A and luminal B tumors are similar in that both are typically ER+ or PgR+, or both. However, they are dissimilar in that the A type is usually HER2-and the B type is more likely to be HER2+ and lymph nodepositive.Women with luminal Atumors are often diagnosed at a younger age. They tend to have the best prognosis, with relatively high rates of overall survival and relatively low rates of recurrence. Those with luminal B tumorstend
doi:10.21474/ijar01/3580 fatcat:pwjeydex3rcfzkz45obdmky23u