Characteristics of triple-negative breast cancer

Abstract

BackgroundTriple-negative breast cancers (TNBC) neither express hormone receptors, nor overexpress HER2. They are associated with poor prognosis, as defined by low five-year survival and high recurrence rates after adjuvant therapy. Overall, TNBC share striking similarities with basal-like breast cancers (BBC), so a number of studies considered them being the same. The purpose of this review is to summarise the latest findings on TNBC concerning its relation and delineation to BBC, discuss the developmental pathways involved and address clinical implications for this complex type of breast cancer.MethodsThe recent literature from PubMed and Medline databases was reviewed.ResultsNot all TNBC are of the intrinsic BBC subtype (nonbasal (NB)-TNBC), nor are all BBC triple-negative (non-triple-negative (NTN)-BBC). There is increasing evidence that a triple-negative, basal-like breast cancer (TNBBC) subtype develops mainly through a BRCA1-related pathway. Somatic mutations that contribute to NTN-BBC and NB-TNBC development are possibly not related to this pathway, but may occur randomly due to increased genomic instability in these tumours. Several therapeutic options exist for TNBBC, which exhibited promising results in recent clinical trials. Cytotoxic therapies, e.g. combined treatment with anthracyclines or taxanes, achieved good tumour regression rates in the neo-adjuvant setting, but also showed considerable recurrence during the first 5 years after therapy. Targeted therapy options involve PARP1 and EGFR inhibition, although both approaches still need further investigation.ConclusionsTNBC and BBC are not the same disease entity. The TNBBC subtype shows the largest homogeneity in terms of tumour development, prognosis and clinical intervention options.

Different Prognostic Factors Correlate with Bcl-2 Expression among Triple Negative and Non-Triple Negative Breast Cancers

“…This is not surprising because a recent study proved that Bcl-2 is a prognostic factor in women with both ER positive and ER negative disease and also in women with both Her2 negative and Her2 positive disease and its positivity is maintained across various molecular subtypes of breast cancer (Dawson et al, 2010). Although the frequency of Bcl-2 expression ranged from 69-73% in previous studies (Dawson et al, 2010;Kallel-Bayoudh et al, 2011), a controversy exists because they found that TNBC tend commonly to have lower Bcl-2 expression compared to non-TNBC (Tawfik et al, 2010;de Ruijter et al, 2011), moreover, Bcl-2 oncogene expression was found to be statistically greater in the ER positive breast tumors compared to ER negative tumors (dos Santos et al, 2008). Such discrepancies between the studies are likely to be due to the wide variation between the methodologies and types of cases studied (Cecka et al, 2008).…”

“…Based on histopathological characteristics, the World Health Organization has defined a wide range of invasive breast cancer subtypes (Tavassoli and Devilee, 2003 ). Unfortunately, this way of categorizing breast tumors fails to predict prognosis and treatment possibilities (de Ruijter et al, 2011). Recently, gene-expression analysis-based studies subdivided breast carcinomas into molecular subtypes (Perou et al, 2000;Sorlie et al, 2001).…”

Clinicopathological Characteristics of Triple Negative Breast Cancer at a Tertiary Care Hospital in India

“…While basal-like breast cancer (BLBC) was originally a term used for a molecular subtype, the term TNBC applies to tumors which are negative for expression of ER, PR and HER2 on immunohistochemistry (IHC). Some authors have claimed that the basal type is composed almost entirely of TNBC and therefore, the TNBC phenotype could reliably be used as a surrogate for the basal type (De Ruijter et al, 2011). However, Rouzier et al (2011) revealed that ER and HER2 expression were seen in 5% and 14%, respectively of basal type those had been diagnosed by gene expression profiling.…”

Down-regulating HIF-1α by lentivirus-mediated shRNA for therapy of triple negative breast cancer

“…5 In particular, patients with triple negative breast cancer (TNBC) have the poorest prognosis, with the 5-year survival rate being lower than 30%. 6,7 Therefore, there is an urgent need for developing novel approaches to overcoming the limitations of current breast cancer therapies.…”