• to give examples of genes which, if mutated, predispose to breast cancer

BRCA1 and BRCA2 are the two main genes effected

Gene sequencing is undergone to check for these mutations

BRCA1 mutations (often result in a truncated protein)

Breast cancer risk = increased by 50-80%

Ovarian cancer risk = 40% increase

Often people are predisposed to cancer if they have a germline mutation in a BRCA1 or 2 gene. a germline mutation is a mutation you are born with, it is genetic/hereditary. these are tumour suppressor genes and they require 2x mutations to become cancerous. a somatic mutation is a mutation that happens throughout your living life caused by a variety of things eg smoking etc etc. if a person already has a germline mutation then they only require one more chance mutation for the gene to become cancerous and so the risk is massively increased this is usually what the BRCA1 n 2 gene defects are and what they mean!

BRCA2 mutations

caused by the founder effect (a group or population mostly segregated eg orkney islands)

BRCA1 vs BRCA2 roles

BRCA1 is involved in repairing double-strand DNA breaks through a process called homologous recombination. It helps to stabilize DNA replication forks and promotes the repair of damaged DNA

• BRCA2 interacts with other proteins, including RAD51, to facilitate the repair of damaged DNA and maintain genomic stability.
• While BRCA2's precise role in DNA repair is not fully understood, it is believed to assist in the assembly of RAD51 filaments on single-strand DNA during homologous recombination.