A breast cancer gene is not a gene that causes cancer, but is a gene that regulates the growth and production of normal breast cells in the breast that is itself functioning abnormally. BRCA1 and BRCA2 genes are present in all people and faulty or not, can be passed to blood relatives. A breast cancer gene can therefore be hereditary and having a relative with breast cancer can increase the risk of developing the condition over time.
Genes are particles inside chromosomes, existing within cells in the human body. Genes are made from a substance called deoxyribonucleic acid, also known as DNA. This substance contains the blueprint for life or more specifically, the human or animal it exists within. DNA instructs the body on how to construct proteins which create the body itself and all of its characteristics. Each human has different DNA, hence we all look, sound and behave differently.
Occasionally a faulty gene occurs. Each cell within the body that contains the gene will contain the fault. Since genes are blueprints for proteins that create different cells, having faulty genes will result in faulty cells being created. These faulty cells multiply to create many more cells containing faulty genes.
BRCA1 and BRCA2 caretaker genes exist in all humans and are responsible for cleaning up and regulating other genes occurring within the breast. If these two genes are themselves faulty, they cannot fulfill their purpose. The individual is left at higher risk of breast cancer.
Breast cancer is more often due to other factors rather than having a breast cancer gene, such as chance or lifestyle variables. Genetic factors can however, have an effect on the chances of developing breast cancer. The breast cancer gene, or faulty gene, can be passed down through blood relatives.
There is a greater risk of breast cancer in people who have a mother, aunt, sister or even a male family member, who has had breast cancer. The closer the blood relative, for example sister rather than cousin, the greater the risk a person has of carrying the breast cancer gene. People from certain ethnic backgrounds have a greater risk of carrying the breast cancer gene, such as the Ashkenazi Jewish community, as do people with a family history of other cancers, for example, pancreatic or ovarian cancers.
Faults occurring in cells are called mutations. Many mistakes are usually required within the genetic code of a cell before it becomes cancerous. Cancerous cells often die before they have a chance to multiply, or they are killed off by the immune system. It therefore requires time for cancer to develop under usual circumstances, hence the breast cancer gene may only have an effect on individuals in later life, or never at all.
