We have previously described three mechanisms of resistance in GBM cells treated with TMZ, increased intracellular communication (Munoz et al., 2014a), miRNA regulation of Sonic Hedgehog signaling (Munoz et al., 2014a), and EGFR regulation of the MDR1 gene (Munoz et al., 2014a). The gene discussed is EGFR; the disease is glioblastoma.