Further investigation of the effects of PRIMA-1MET in established GBM cell lines showed that wtp53/MGMT-negative U87MG cell line displayed relatively strong basal levels of p21, heightened sensitivity to PRIMA-1MET, G1/M arrest and was the only cell line undergoing a senescent phenotype in response to PRIMA-1MET. Here, MGMT is linked to glioblastoma.