The CHEK2 *1100delC mutation is the most common “truncating” mutation (causing a shortened protein) in the CHEK2 gene among Europeans, with lifetime breast cancer risk in the range of 20-30% among female carriers. Results of data pooled from over 30 studies which included 40,000 breast cancer cases and 40,000 controls, showed that estrogen receptor (ER) positive breast cancer was significantly (i.e., 2.5-fold) more common for CHEK2 *1100delC carriers compared to non-carriers.1 Furthermore, breast cancer risk decreased with advancing age. CHEK2 mutation status and other familial risk factors may now be taken into account through a publicly available risk model, called BOADICEA, to provide women with a more precise estimate of their lifetime breast cancer risk.2 Another recent Dutch study3 reported that risks of developing cancers other than breast cancer among CHEK2 *1100delC mutation carriers was 15% to 82% higher than non-carriers; however, the exact risks by cancer type could not be calculated. Although these results are based on the *1100delC mutation, it is possible that this information may be applied to those with other truncating mutations in the CHEK2 gene. This type of data is crucial to help refine the level of cancer risk and the types of associated cancers among those with mutations in moderate risk genes as well as newer genes to best guide cancer risk management strategies.
1Schmidt, MK, et al. J Clin Oncol. 2016 Aug 10;34(23):2750-60. PMID: 27269948.
2Lee, A et al. Genet Med. 2016 Apr 14 . PMID: 27464310. 3Näslund-Koch, C., et al. J Clin Oncol. 2016 Apr 10;34(11):1208-16. PMID: 26884562.