Breast as every cell is sustaining DNA lesions, this

Breast cancer is one of the most significant causes of
cancer death. It’s a disease in which cells in the breast become abnormal and
multiply uncontrollably to form a tumor. It is considered as one the most
common cancer in women worldwide and accounts for 25.1% of all cancers
(Ghoncheh et al., 2016). The tumor suppressor genes for breast cancer called
BRCA1 and BRCA2 genes, which stands for BReast CAncer, were
discovered in the 1990s. Dr. Mary-Claire King and her group began the research
in 1979 to determine why some families were severely affected by breast cancer.
They found that women whose sisters or mothers are affected by the disease have
a higher lifetime risk to develop breast cancer. Then they located the region
on chromosome 17q21 in families with early-onset breast cancer for which
likelihood of co-inheritance with breast cancer (Hurst, 2014). In 1990, the
existence of breast cancer genes, which named by Dr. King BRCA1, was proven by
mapping predispositions to young-onset breast cancer to that chromosome in
families (King, 2014). Mark Skolnick at Myriad Genetics in 1994 sequenced
BRCA1, and a year after that Michael Stratton and Richard Wooster mapped BRCA2
in (1995). The DNA is the genetic blueprint which needs to be kept intact, and
as every cell is sustaining DNA lesions, this damage needs to be repaired. The
tumor suppressor BRCA1 and BRCA2 proteins are required for
maintaining chromosomal stability. These proteins play an essential role
in DNA repair, ? homologous
recombination, cell cycle, transcriptional regulation, and protein degradation.
The BRCA germline mutation in either gene leads abnormalities and tumorigenesis
(Hurst, 2014). Approximately 85% of women who carry BRCA1 and BRCA2 mutation
will have the risk of developing breast cancer before age 70? (Tutt and Ashworth, 2002). The
comprehension of cells mechanism in responding and repairing DNA damage is
essential in treatments development. Based on cell repair mechanism, synthetic
lethality concept provides anticancer therapies such as Poly (ADP-ribose)
polymerase (PARP) inhibitors. A decade after discovering BRCA genes, PARP
inhibitors have been proven to be a beneficial treatment for patients with
germline BRCA1/2 mutations (Walsh, 2015).