CHEK2 and breast cancer: Another CHEK2 missense GPV, c.1283C>T (p.Ser428Phe), herein referred to as “S428F”, is established to also confer lower breast cancer risks, with a previously reported odds ratio of 1.26 (95% CI 0.76–2.12; p = 0.37) [14], consistent with estimates from other studies [10,12].