Hereditary Breast and Ovarian Cancer
Breast cancer is a malignant tumour that starts in the cells of the breast. It is a group of cancer cells that can grow into (invade) surrounding tissues or spread (metastasize) to distant areas of the body. The disease occurs almost entirely in women, but men can develop it, too. Worldwide, breast cancer is the most frequently occurring malignant tumour diagnosed and the principal cause of death in women.
The most common hereditary cause of breast cancer is hereditary breast and ovarian cancer syndrome (Hereditary Breast and Ovarian Cancer Syndrome or HBOC), which is caused by a germline mutation in either the BRCA1 or BRCA2 gene. HBOC is characterized by an increased risk for male and female breast cancer, ovarian cancer (includes fallopian tube and primary peritoneal cancers), and to a lesser extent other cancers such as prostate cancer, pancreatic cancer, and melanoma. Germline pathogenic variants in BRCA1 and BRCA2 genes are inherited in an autosomal dominant manner.
In the 1990s, it was demonstrated for the first time that the DNA repair genes BRCA1 and BRCA2 are directly associated with HBOC. Currently, it is estimated that approximately 5–10% of all patients with breast cancer and approximately 20% of all patients with ovarian cancer exhibit a monogenic predisposition to breast and ovarian cancer.
In the past few years more than 25 genes have been associated with familial breast and/or ovarian cancer and still more expected to emerge. Most of the identified HBOC genes encodes for proteins involved in genome maintenance pathways connected with BRCA1 and BRCA2. For example we can found involved genes such as: ATM, BARD1, CHEK2, MLH1, PALB2, PTEN, TP53, FANCC and FANCM.
The risk of breast and ovarian cancer may differ between the individual genes and variants and from family to family. For nearly all of the emerging HBOC genes, it is currently not possible to provide individual accurate risk estimation. However, we can consider that people carrying pathogenic mutations in BRCA1 and BRCA2 genes have a significantly elevated risk of breast and ovarian cancer.
In the early stages of breast cancer, there are no symptoms. The first symptoms of breast cancer are usually an area of thickened tissue in the woman's breast, or a lump, a symptom that is felt only by the patient and may be described as a pain or headache or a rash or swelling.
Other frequent symptoms are:
- A lump in a breast
- A pain in the armpits or breast that does not seem to be related to the woman's menstrual period Pitting or redness of the skin of the breast; like the skin of an orange
- A rash around (or on) one of the nipples
- A swelling (lump) in one of the armpits
- An area of thickened tissue in a breast
- One of the nipples has a discharge; sometimes it may contain blood
- The nipple changes in appearance; it may become sunken or inverted
- The size or the shape of the breast changes
- The nipple-skin or breast-skin may have started to peel, scale or flake.
These symptoms can also be associated with benign ailments but should be discussed with a doctor.
The genetic/hereditary factors have a key role in the breast and ovarian cancer development which makes it difficult to prevent. Nonetheless there are trigger factors which can easily be avoided. Recent studies seem to demonstrate that breast cancer risk can be lowered by regular physical exercise (at least 4 hours/week), keeping an ideal body weight (not overweight or obese) after menopause and avoiding regular alcohol consumption.
Several epidemiological studies have demonstrated that the use of substitute hormonal treatments during menopause is associated with a higher breast cancer risk. This risk can be lowered by avoiding postmenopausal hormone treatments.
Gene or region studied