Medically reviewed by Huma Rana, MD
CHEK2 is the abbreviated name of the gene called checkpoint kinase 2 (gene names are written in italics). The gene provides cells with instructions for making a protein known as CHK2, which becomes active when DNA within the cell is damaged or strands of DNA break.
CHK2 and other proteins respond to the damage by halting cell division and assessing whether the cell is better off repairing the damage or self-destructing for the good of the body. This process ensures that cells with genetic damage or mutations don’t pass the “bad” DNA on to their descendants when they divide. Such mutations can be a first step toward cancer. Because it helps prevent cells from becoming cancerous, CHEK2 is known as a tumor-suppressor gene.
When CHEK2 itself is mutated — when the DNA that constitutes the gene acquires an error — its ability to perform its assigned role is reduced. Without a properly functioning CHEK2 gene, cells lose a key restraint on their growth and may be a step closer to the unbridled division that is characteristic of cancer.
CHEK2 mutations are found in a variety of cancer types, including breast, colon, prostate, kidney, thyroid, and other cancers, according to the National Institutes of Health. The mutations have also been found in some brain tumors and in osteosarcoma, a form of bone cancer.
People born with a CHEK2 mutation have a higher risk of developing certain types of cancer. The risk of breast cancer in women with a CHEK2 mutation is believed to be at least double that of a woman without such a mutation. Because of this increase, women with the mutation are advised to have more intensive breast screenings.
The amount of increased risk of colorectal and prostate cancer linked to a CHEK2 mutation is unclear, but people with such mutations should talk to their primary physicians and genetics team about screening for these cancers.
Most individuals who carry a mutation in CHEK2 have one normal copy of the gene and one mutated copy. Because children inherit one copy of each gene from each of their parents, people with a CHEK2 mutation have a 50% chance of passing on the mutation to their children. And, because CHEK2 mutations are usually genetically transmitted, people who learn they carry such a mutation should inform their close family members so they can be tested for it, if they choose.