Likewise, the reduced expression of 53BP1 decreased the protein expression of ATM, CHK2, and the phosphorylated products associated with the p53 apoptotic pathway, leading to radiotolerance [29], and low tumor tissue 53BP1 expression was an independent predictor of disease-free survival in patients receiving chemoradiotherapy for rectal cancer [30]. Here, CHEK2 is linked to neoplasm.