Other Names: BROVCA1, Familial susceptibility to breast-ovarian cancer 1
BRCA1 Hereditary Breast and Ovarian Cancer Syndrome (BRCA1 HBOC) is an inherited condition that is characterized by an increased risk for a variety of different cancers. Women with this condition have a 57-60% risk of developing breast cancer, a 40-59% risk of developing ovarian cancer and an 83% risk of developing contralateral breast cancer by age 70. Men have a 1% lifetime risk of breast cancer and an increased risk for prostate cancer. BRCA1 HBOC may also be associated with an elevated risk for cancers of the cervix, uterus, pancreas, esophagus, stomach, fallopian tube, and primary peritoneum; however, these risks are not well defined. This condition is caused by changes (mutations) in the BRCA1 gene and is inherited in an autosomal dominantmanner. Management may include high risk cancer screening, chemoprevention and/or prophylactic surgeries.

A diagnosis of Hereditary Breast and Ovarian Cancer Syndrome (HBOC) is considered when there are multiple cases of breast cancer and/or ovarian cancer on the same side of the family. The chance that a family has HBOC increases in any of these situations:

  • One or more women are diagnosed at age 45 or younger
  • One or more women are diagnosed with breast cancer before age 50 with additional family history of cancer, such as prostate cancer, melanoma, and pancreatic cancer
  • There are breast and/or ovarian cancers in multiple generations on the same side of the family, such as having both a grandmother and an aunt on the father’s side both diagnosed with these cancers
  • A woman is diagnosed with a second breast cancer in the same or the other breast or has both breast and ovarian cancers
  • A male relative is diagnosed with breast cancer
  • There is a history of breast cancer, ovarian cancer and/or pancreatic cancer on the same side of the family
  • There is a history of breast and/or ovarian, pancreatic, or male breast cancer in a family of Ashkenazi Jewish ancestry

HBOC is an inherited genetic condition. This means that the cancer risk is passed from generation to generation in a family. Two genes are associated with the majority of HBOC families: BRCA1 and BRCA2. BRCA stands for BReast CAncer. Other, less common genes have also been associated with an increased risk of developing breast and other cancers, such as mutations in the TP53, PTEN, CDH1, ATM, CHEK2 or PALB2 tumor suppression genes and many others. Blood tests now include many of these genes in a single, multiple-gene panel test. A mutation (alteration) in either BRCA1 or BRCA2 gives a woman an increased lifetime risk of developing breast and ovarian cancers. Men with these gene mutations also have an increased risk of breast cancer and prostate cancer.