In less than 5% of cases, genetics plays a more significant role by causing a hereditary breast–ovarian cancer syndrome. This includes those who carry the "BRCA1" and "BRCA2" gene mutation. These mutations account for up to 90% of the total genetic influence with a risk of breast cancer of 60–80% in those affected. Other significant mutations include "p53" (Li–Fraumeni syndrome), "PTEN" (Cowden syndrome), and "STK11" (Peutz–Jeghers syndrome), "CHEK2", "ATM", "BRIP1", and "PALB2". In 2012, researchers said that there are four genetically distinct types of the breast cancer and that in each type, hallmark genetic changes lead to many cancers.