CHEK1 and cancer: HMGA2 also interacts with ataxia telangiectasia and Rad3-related kinase (ATR) and HMGA2-mediated activation of the ATR–checkpoint kinase 1 (CHK1) signaling pathway with resulting G2/M arrest increases chemoresistance against BER-inducing genotoxic alkylating agents in human thyroid and other cancer cells (17).