The Epigenetics of Triple-Negative and Basal-Like Breast Cancer: Current Knowledge

Abstract

Breast cancer has the highest incidence among all malignancies diagnosed in women. Therapies have significantly improved over the years due to extensive molecular and clinical research; in a large number of cases, targeted therapies have provided better prognosis. However, one specific subtype remains elusive to targeted therapies–the triple-negative breast cancer. This immunohistochemically defined subtype is resistant to both endocrine and targeted therapies, leading to its poor prognosis. A field that is of great promise in current cancer research is epigenetics. By studying the epigenetic mechanisms underlying tumorigenesis–DNA methylation, histone modifications, and noncoding RNAs–advances in cancer treatment, diagnosis, and prevention are possible. This review aims to synthesize the epigenetic discoveries that have been made related to the triple-negative breast cancer.

Long non-coding RNA LRRC75A-AS1 facilitates triple negative breast cancer cell proliferation and invasion via functioning as a ceRNA to modulate BAALC

“…As one of the most common female malignancy, breast cancer (BC) is the major cause of female fatality globally, accounting for around 6.6% of global cancer fatality rate 1 . BC is characterized by high heterogeneity and contains at least five subtypes: HER2 overexpressing, Luminal A, Luminal B, and triple-negative breast cancers (TNBC), which are generally divided into basal-like and claudinlow subtypes 2,3 . TNBC is featured by lacking the expression of estrogen receptors and progesterone receptors 4 .…”

Promoter Hypermethylation and Expression Changes of BRCA1 Gene in a Cohort of Sporadic Breast Cancer Cases among Pakistani Population

“…Up to 30% of triple negative cases have a germline mutation (Greenup et al, 2013). However, a large frequency of tumors share the molecular characteristics of BRCAness (Quigley et al, 2017) and there is a strong relation between the two entities, leading to a worse prognosis (Temian et al ., 2018). Aberrant DNA methylation regulated by abnormal expression of DNA methyl-transferase is the most well-studied epigenetic change, which culminates in altered gene expressions and BRCAness (Kanwal et al, 2015).…”

Association of HDAC8 Expression with Pathological Findings in Triple Negative and Non-Triple Negative Breast Cancer: Implications for Diagnosis

“…Researchers are currently studying HDAC and its inhibitors. Recent investigations have displayed a direct correlation between breast tumors and differences in histone proteins [11,12] . Equilibrium between the acetylation and deacetylation of nuclear histones is essential for the regulation of gene expression.…”