CHEK2 and neoplasm: Unmethylated cytidine-phosphate-guanosine (CpG) motifs (CpG ODNs), a TLR9 agonist, can stimulate antitumor immunity by activating the NF-κB pathway [5,62–64], and increase tumour cell death via cell cycle S phase arrest triggered by phosphorylated CHK2 [65–69].