Breast cancer risks were recently reported among a sample of 423 women with mutations in one of the Lynch syndrome genes (MLH1, MSH2, MSH6, or PMS2).1 Results indicated that breast cancer risks were substantially higher among those with MSH6 and PMS2 mutations, compared to MLH1 and MSH2 mutations. In fact, breast cancer risk to age 60 was 37.7% for PMS2, 31.1% for MSH6, 16.1% for MSH2, and 15.5% for MHL1. These findings are consistent with another recent study of 528 patients with Lynch syndrome gene mutation (including MLH1, MSH2, MSH6, PMS2, and EPCAM) in which PMS2 and MSH6 mutations were much more frequent among those with only breast cancer, whereas MLH1 and MSH2 mutations were much more frequent among those with only colorectal cancer.2 These studies highlight how the risk profile among patients with Lynch syndrome is continuing to evolve as more individuals are tested through multi-gene panel testing, with particular focus on the complexities of the PMS2 mutation carrier phenotype.3
1Roberts ME, et al. Genet Med. 2018 Jan 18. PMID: 29345684.
2Espenschied CR, et al. J Clin Oncol. 2017 Aug 1. PMID: 28514183.
3Blount J, et al. Clin Genet. 2018 Jul. PMID: 29286535.