Furthermore, no sensitization to TMZ + ATRi was observed in MGMT+ve lines in the absence of AZD5896 (data not shown), demonstrating that ATR protects against O6-MeG cytotoxicity as reported [20] and confirming the recent report that MGMT+ve cells glioblastoma cells are not sensitized to TMZ by ATR inhibition [21]. Here, MGMT is linked to glioblastoma.