CHEK2 and breast cancer: Pathogenic germline variants in Partner And Localizer of BRCA2 (PALB2), ATM Serine/Threonine Kinase (ATM), BRCA1 Associated RING Domain 1 (BARD1), and Checkpoint Kinase 2 (CHEK2) individually increase breast cancer risk, while TP53, Phosphatase And Tensin Homolog (PTEN), Serine/Threonine Kinase 11 (STK11), Neurofibromin 1 (NF1), and CDH1 mutations increase breast cancer risk in association with genetic syndromes [24,25].