ICARE Newsletter Winter 2017

Characterizing Breast Cancers That Develop Among Women with a CHEK2 Mutation

With increasing use of multi-gene panel tests, one of the genes in which mutations are frequently detected among breast cancer patients and others is the CHEK2 gene. This gene has been shown to have a 2-3 fold excess risk for breast cancer. There are many CHEK2 mutations that have been identified that generally fall into two broad categories: those that prematurely shorten the protein that is made from the gene (called “truncating” mutations) and those that change a single base pair within the gene that impairs it from working normally (called “missense” mutations). Most completed studies have focused on a specific “truncating” mutation called “1100delC”, as it is a relatively common change particularly among European populations.

A few studies have tried to assess if breast cancers associated with CHEK2 mutations may have specific characteristics, although results have not been consistent. For example, a study from 2014 which included 3 CHEK2 truncating mutations (including the 1100delC mutation) found no differences in survival between those with and without mutations,2 while an earlier study from 2012 suggested that these CHEK2-associated breast cancers might have a poorer prognosis.1 More recently, a study focused on a CHEK2 missense mutation (p.1157T) suggested this change was not associated with poorer prognosis. Overall, there is currently insufficient evidence to conclude an association between a CHEK2 mutation and poorer breast cancer prognosis; however, additional studies are warranted to better understand this relationship.

1Weischer M, et al. J Clin Oncol. 2012 Dec 10. PMID: 23109706.
2Huzarski T, et al. Breast Cancer Res Treat. 2014 Apr. PMID: 24557336.
3Muranen TA, et al. Breast Cancer Res. 2016 Oct 3. PMID: 27716369.