Checkpoint kinase 2, or CHEK2, for short, is a gene that normally helps with DNA repair. If a person has a mutation or variation, in this gene, may have an increased risk of developing cancer.
Mutations to the CHEK2 gene have been linked to a wide range of cancers:
- Breast cancer
- Ovarian cancer
- Prostate cancer
- Colon cancer
- Kidney cancer
- Thyroid cancer
- Brain tumors
Scientists have also found that some people with a CHEK2 mutation develop Li-Fraumeni syndrome — a rare hereditary condition that’s usually associated with the TP53 gene.
CHEK2 gene mutations belong to Class II mutations in genes that are involved in processes of DNA replication, transcription, recombination, and reparation. The genes encode various enzymes (e.g., polymerases, helicase, topoisomerase, etc.) and cell cycle-regulating proteins. Defects in these genes result in chromosomal instability and therefore can lead to different cancer diseases.
The CHEK2 gene (cell-cycle checkpoint kinases 2) encodes a protein called the cell cycle checkpoint regulator, which is involved in DNA repair processes and in cell division regulating processes. The product of this gene is an enzyme called protein kinase enzyme which is synthesized in response to damage to DNA molecules. The mechanism of action is to block the cell cycle in the G1 phase or launch the apoptosis process while suppressing the malignant transformation of cells. CHEK2 gene mutations lead to the expression of defective truncated protein and they are associated with the emergence of different inherited forms of malignancies. Three mutations are the most important in the CHEK2 gene: 1100delC, IVS2 + 1G> A, and 470T> C Ile157Thr.
Indications for genetic testing of the CHEK2 gene are:
- Family history (breast cancer, prostate cancer, or colorectal cancer in first-degree relatives)
- One or more relatives with the same type of tumor
- Atypical proliferative breast diseases
- Multiple primary tumors in the same organ
- Multiple primary tumors in different organs
- Multiple primary tumors in paired organs
- Multifocality inside one organ
- Tumor manifestations at an early age
- Two or more relatives with rare forms of cancer
- Two or more relatives with tumors related to a family cancer
- Three or more relatives in two generations with tumors of one localization
- Negative test results for BRCA1 and BRCA2 gene mutations