Similarly, evidence that OGG1-initiated BER can be detrimental includes reports that OGG1 loss reduces cytotoxicity and DNA breaks caused by 8-oxodGTP in A549 cancer cells63, H2O2-induced PARP1 overactivation and DNA breaks in MEFs64 and H2O2-induced telomere breaks in HeLa cells65. Here, PARP1 is linked to cancer.