New gene as cause of breast cancer

Researchers have identified a gene that when mutated can lead to an elevated but modest risk of breast cancer. The altered gene, called CHEK2 or CHK2, can double the estimated risk of breast cancer. It is believed to be associated with 1% of all female and 9% of male breast cancers. However the known breast cancer genes BRCA1 and BRCA2 are considered "riskier". About 50% to 60% of women with these particular genes develop cancer by 70 years of age. Researchers at the Institute of Cancer Research in Surrey, UK, established that the CHEK2 mutations were found in 5.1% of 1,071 breast cancer patients without a mutation in the BRCA1 or BRCA2 genes. However, only 1.1% of 1,620 healthy people were found to have the gene variation. The CHEK2 gene is located on human chromosome 22 and plays a role in the repair of damaged DNA. DNA damage can cause cancer and thus if the function of CHEK2 in repairing DNA is reduced then the risk of developing cancer is higher. The researchers believe that CHEK2 can cause breast cancer by acting together with another gene that has so far not been identified. This new discovery contributes to the small but growing body of ongoing research into the role of genes in breast cancer. About 1 percent of the general population - both women and men - carry the mutated gene. By being a carrier one is not necessarily destined to develop breast cancer but it is a fact that a family history of breast cancer is considered to be one of the strongest risk factors for the disease particularly in young women. Nearly half of the women with early-onset breast cancer have a family history of breast or ovarian cancer and yet only 9% of these women have a BRCA1 or BRCA2 mutation. This is suggestive of other genetic factors that may play a role. These findings indicate that there are biological pathways and other genes that are involved in breast cancer. This information would be useful in developing a new approach to the treatment of this type of cancer.

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