What is the breast cancer gene?
The development of breast cancer (mamma carcinoma) can have many different causes. In some cases it can be traced back to a gene mutation. However, it is assumed that only 5-10% of breast cancer cases are based on a hereditary genetic cause.
In this case one speaks of hereditary breast cancer. The most common cause is a mutation of the BRCA-1 or BRCA-2 gene. BRCA stands for BReast CAncer.
What influence does the breast cancer gene have on the breast cancer risk?
A mutation of the BRCA-1 or BRCA-2 gene increases the risk of developing breast cancer by up to 80%. In comparison, women without a gene mutation have a 10% risk of developing breast cancer by the age of 85. Furthermore, the age of onset of the disease is reduced.
Women who carry the gene develop breast cancer on average 10-20 years earlier than women without a family risk. The disease often occurs before the age of 50. Conspicuous and an indication of a gene mutation is a bilateral occurrence of breast cancer as well as the occurrence in men, who usually contract a very aggressive variant.
If there is a mutation in the BRCA1 or BRCA2 gene, not only the risk of breast cancer but also of other types of cancer is increased. Ovarian cancer (cancer of the ovaries) is particularly worthy of mention. However, there is also an increased risk of cancer of the colon, pancreas, stomach and prostate. More recent research is gradually discovering other genes that can lead to breast cancer (e.g. RAD51C). Often, if a gene mutation is present, there are several cases of breast cancer in the family, often with an early onset of the disease in the respective individuals.
What is the BRCA-1? What is the BRCA-2?
Hereditary gene mutations are present in all body cells from birth. They are passed on via the parental germ cells, including the BRCA-1 and BRCA-2 genes. These have a protective effect on the somatic cells when they are intact.
They are said to prevent cancer development in the cells. Therefore they are called “tumour suppressor genes”. However, if the BRCA gene does not function properly, it can no longer fulfil its protective function and the risk of developing cancer increases rapidly.
Studies to increase the risk are not easy. Recent figures have shown the following risk increase for a gene mutation in BRCA-1: 72% risk of developing breast cancer up to the age of 80. BRCA-1 mutations lead to cancer on average about 10 years earlier.
40% risk of a second, new breast cancer on the other side within the next 20 years 44% risk of ovarian cancer In comparison, the following risk increase results from a BRCA-2 mutation: 69% disease risk for breast cancer up to the age of 80 years 26% risk of a second, new breast cancer on the other side within the next 20 years 17% risk of ovarian cancer The figures show that a gene mutation means a significant risk increase for those affected. BRCA-1 in particular carries a high risk. Therefore, a detailed examination and questioning of possible gene carriers is indispensable.
Particularly in the case of increased occurrence in a family (positive family history) with early onset of the disease and rapid progression, the individuals should be closely examined and follow-up checked. – 72% risk of breast cancer up to the age of 80 years. BRCA-1 mutations lead to cancer on average about 10 years earlier. – 40% risk of a second, new breast cancer on the other side within the next 20 years
- 44% risk of ovarian cancer
- 69% risk of breast cancer up to the age of 80
- 26% risk of a second, new breast cancer on the other side within the next 20 years
- 17% risk of ovarian cancer
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