Breast cancer develops when the cells that make up healthy breast tissue progressively develop numerous genetic mutations. These mutations eventually allow the cell to proliferate rapidly and continually while evading cellular death. As the cancer progresses, additional genetic mutations allow the cancer cells to migrate into other tissues and eventually colonize several organs throughout the body. Inherited mutations present from birth play a role in the risk of developing breast cancer, with several key genes involved in a family history of breast cancer.
BRCA1/2 Mutations
A very common set of genetic mutations involved in familial breast cancer are mutations to two genes: BRCA1 and BRCA2. These closely related genes normally work together to protect the cell from cancer. When a breast cell develops a genetic mutation, BRCA1 and 2 allow the cell to correct the mutation before it continues to divide, slowing the rate at which the cell develops permanent genetic mutations. Inherited mutations to BRCA1 or 2 can interfere with the normal function of these genes, so breast cells can more easily develop genetic mutations that promote cancer development. As a result, patients who inherit a mutant copy of BRCA1 or BRCA2 have a marked increase in their risk of developing breast cancer. Patients with these mutations typically have a family history of breast cancer, including male breast cancer. The National Cancer Institute indicates that women with a family history of breast or ovarian cancers may undergo genetic testing to screen for BRCA1/2 mutations and assess their risk of developing breast cancer.
ATM Mutations
Mutations to the ATM gene have also been linked to a family history and increased risk of developing breast cancer. Like BRCA1 and 2, ATM works to protect cells from developing cancer. ATM normally functions to stop the cell from dividing following radiation damage. It helps allow the cell to repair itself before it continues dividing, so that the cell does not accumulate genetic mutations easily. The Genome News Network indicates that women with a mutant ATM gene have nine times the risk of developing breast cancer compared to women with functional ATM genes. As a result, ATM mutations could lead to a family history of breast cancer as the mutation is passed down from generation to generation. The development of ATM genetic testing in the future may allow doctors to assess a patient's risk for familial breast cancer.
PTEN Mutations
Mutations to the gene PTEN may also contribute to a family history of breast cancer and increase the risk of developing breast cancer. PTEN works as a tumor suppressor protein--it helps slow down normal cell proliferation and aids in programmed cellular death after cell damage. Mutations to the PTEN gene help allow breast cells to proliferate out of control and avoid cell death, ultimately contributing to cancer development. The American Cancer Society also indicates that PTEN mutations cause Cowden Syndrome, a genetic disease characterized by the development of benign or cancerous breast tumors. Patients with a family history of Cowden Sydrome or breast cancer may undergo screening for PTEN mutations to determine their risk of developing breast tumors and breast cancer.
