CHEK2 and breast cancer: Besides, mutations in tumor protein p53 (TP53) [19], phosphatase and tensin homolog (PTEN) [20], serine/threonine kinase 11 (STK11), cadherin 1 (CDH1) [21], partner and localizer of BRCA2 (PALB2) [22] and checkpoint kinase 2 (CHEK2) [23] were also associated with an increased risk of breast cancer.