Library · Genetics
BRCA1 and BRCA2
Make it clearer
BRCA1 and BRCA2 are two genes, that is, two sets of instructions written in DNA. Each one carries the instructions for making a tumor suppressor protein, the kind that keeps cells from growing and dividing out of control, and both take part in repairing damaged DNA.
There are two copies of each gene. Almost everyone who inherits a harmful variant, a version of the gene that does not work properly, still has the second normal copy, and with it the cell keeps repairing DNA. The problem shows up if that second copy is also altered in a given cell: that cell can no longer repair DNA well and can turn cancerous. It is like being left with a single spare key: as long as you have it, the door opens.
That is why the risk of breast and ovarian cancer rises sharply in someone who inherits one of these variants. A higher risk is not the same as having the disease: not everyone who inherits one develops cancer.
In brief
BRCA1 and BRCA2 are two genes whose proteins act as tumor suppressors and help repair damaged DNA.
Almost everyone who inherits a harmful variant still has a second normal copy; if that copy is altered in a cell, that cell no longer repairs DNA well and can turn cancerous.
It is like being left with a single spare key: as long as you have it, the door opens.
The risk of breast and ovarian cancer rises sharply with that inherited variant, although not everyone who inherits it develops cancer.
Sources (3)
- MedlinePlus Genetics, U.S. National Library of MedicineBRCA1 gene, MedlinePlus GeneticsPublished
- MedlinePlus Genetics, U.S. National Library of MedicineBRCA2 gene, MedlinePlus GeneticsPublished
- National Cancer InstituteBRCA Gene Changes: Cancer Risk and Genetic Testing
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated