Variations of the BRCA1, BRCA2, CDH1, PTEN, STK11, and TP53 genes increase the risk of developing breast cancer.
The AR, ATM, BARD1, BRIP1, CHEK2, DIRAS3, ERBB2, NBN, PALB2, RAD50, and RAD51 genes are associated with breast cancer.
Cancers occur when a buildup of genetic mutations in critical genes—those that control cell growth and division or the repair of damaged DNA—allow cells to grow and divide uncontrollably to form a tumor. In most cases, these genetic changes are acquired during a person's lifetime and are present only in certain cells. These changes, which are called somatic mutations, are not inherited. Less commonly, gene mutations inherited from a parent increase the risk of developing cancer. In people with these inherited genetic changes, additional somatic mutations in other genes must occur for cancer to develop.
In addition to specific genetic changes, researchers have identified many personal and environmental factors that may influence a person's risk of developing breast cancer. These factors include gender, age, ethnic background, a history of previous breast cancer, certain changes in breast tissue, and hormonal factors. A history of breast cancer in closely related family members is also an important risk factor, particularly if the cancer occurred at an early age. Some breast cancers that cluster in families are associated with inherited mutations in particular genes, such as BRCA1 or BRCA2.
BRCA1 and BRCA2 are major genes related to hereditary breast cancer. Women who have inherited certain mutations in these genes have a high risk of developing breast cancer, ovarian cancer, and several other types of cancer during their lifetimes. Men with BRCA1 mutations also have an increased risk of developing breast cancer. Additionally, BRCA1 mutations are associated with an increased risk of pancreatic cancer. Mutations in the BRCA2 gene are associated with an increased chance of developing male breast cancer and cancers of the prostate and pancreas. An aggressive form of skin cancer called melanoma is also more common among people who have BRCA2 mutations.
Inherited changes in several other genes, including CDH1, PTEN, STK11, and TP53, have been found to increase the risk of developing breast cancer. Mutations in these genes cause syndromes that greatly increase the chance of developing several types of cancer over a person's lifetime. Some of these syndromes also include other signs and symptoms, such as the growth of noncancerous (benign) tumors.
Some research suggests that inherited variants of the ATM, BARD1, BRIP1, CHEK2, NBN, PALB2, RAD50, and RAD51 genes, as well as certain versions of the AR gene, may also be associated with breast cancer risk. Not all studies have shown these connections, however. Of these genes, ATM and CHEK2 have the strongest evidence of being related to the risk of developing breast cancer.
Noninherited (somatic) mutations also have been identified in breast tumors. For example, somatic mutations in the ERBB2 (also called Her-2/neu), DIRAS3, and TP53 genes have been associated with some cases of breast cancer.
Read more about the AR, ATM, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, DIRAS3, ERBB2, NBN, PALB2, PTEN, RAD50, RAD51, STK11, and TP53 genes.