In the most type of breast cancer, the root cause is usually a change or a mutation in DNA. Mutations in some genes can result in breast cancer.
Some of these genes can be inherited, and this can increase the risk of developing breast cancer. Mutated BRCA genes can be inherited, and this increases the risk of breast cancer.
Mutations can also be acquired; this means that a person can have mutations in their own when born or later in life.
Mutations in genes that regulate cell growth, division, and cell death can cause breast cancer (proto-oncogenes and tumor suppressor genes).
Once these genes lose control, abnormal cells begin to grow in an unregulated pattern, and this can lead to cancer. For instance, BRCA1 and BRCA2 are tumor suppressor genes that suppress the growth of abnormal cells, but when it is mutated, it increases the risk of developing breast cancer.