CHEK1 and prostate carcinoma: Recently, using human bone osteosarcoma, non-small-cell lung cancer (NSCLC) and prostate cancer cell lines in vitro, Sato et al. have shown for the first time that an increase in PD-L1 expression can emerge as a direct consequence of radiation induced DNA DSBs which was regulated by ATM/ATR/Chk1 kinases, the key enzymes involved in DNA damage signaling43.