In addition, Western blot analysis of DNA damage markers (ATM, Chk2, and γH2AX) revealed that the levels of p-ATM, p-Chk2 and γH2AX in the OE-CTSB group were markedly higher than those in the RB group, while the levels of these proteins in the si-CTSB group were significantly lower than those in the RB group. This evidence concerns the gene ATM and retinoblastoma.