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Studies show that 5% to 10% of all breast cancers are hereditary, caused by a gene change (mutation) passed down from a parent. Hundreds of genes are associated with breast cancer, but some of them play a bigger role in increasing the risk of breast cancer. Having an inherited gene mutation doesn’t mean you will surely develop breast cancer — it means you have a higher risk.

Different gene mutations are passed down in different forms. BRCA1 and BRCA2 gene mutations, for example, are passed down in an autosomal dominant pattern, which means inheriting even one bad gene from one parent increases the risk of gene mutation. Gene testing can help you determine if you have certain high-risk gene mutations. Below, we highlight some of the common breast cancer gene mutations.

Breast Cancer Gene Mutations:

  • ATM
  • BARD1
  • BRIP1
  • BRCA1
  • BRCA2
  • CDH1
  • CHEK2
  • NBN
  • NF1
  • PALB2
  • PTEN
  • RAD51C
  • RAD51D
  • STK11
  • TP53


The BRCA1 (breast cancer gene one) and BRCA2 (breast cancer gene two) mutations are the most high-risk gene mutations, responsible for over 10% of all hereditary breast cancers. Furthermore, BRCA mutations also increase the risk of pancreatic cancer, ovarian cancer, and prostate cancer (in men). Women with BRCA1 and BRCA2 gene mutations have a 72% risk of breast cancer.


The PALB2 gene usually produces a protein that repairs damaged DNA and prevents the growth of tumors. However, women with PALB2 gene mutations have a 14% risk of breast cancer by the age of 50 and a 35% risk of breast cancer by the age of 70.


The PIK3CA gene facilitates the production of certain proteins that are necessary for cellular functions. This is a sporadic rather than inherited mutation, which means it can only be developed during your lifetime rather than being passed down. Approximately 30% to 40% of all breast cancers display PIK3CA gene mutations. Identifying PIK3CA mutation helps doctors curate the ideal treatment plan.


The HER2 gene produces human epidermal growth factor receptor 2, a special protein that helps all breast cells grow. However, HER2 gene mutations can lead to the production of excess HER2 proteins, which, in turn, makes your breast cells grow uncontrollably. Approximately 10% to 20% of all breast cancers display HER2 gene mutations — this is a sporadic mutation rather than an inherited one.


The TP53 gene prevents cells with damaged DNAs from growing. However, an inherited TP53 gene mutation leads to the Li-Fraumeni syndrome, increasing the risk of brain tumors, leukemia, and breast cancer. Women with Li-Fraumeni syndrome because of TP53 gene mutations have a 54% risk of breast cancer by the age of 70.

Genetic Testing & Counseling in Wellesley, MA

At New England Breast and Wellness, we perform genetic testing to identify possible gene mutations that may increase the risk of breast cancer. Dr. Katherina Calvillo curates an individualized patient care program to perform genetic testing for specific abnormalities or larger panel tests to examine multiple genes. If you have strong risk factors for breast cancer, such as a family history of cancer, please consult Dr. Calvillo in Wellesley.

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