Regarding CNUs, it was reported that knockdown of the AP-1 component FRA1 sensitizes glioma cells towards ACNU via the attenuation of CHK1 phosphorylation and abrogation of the G2/M arrest [34], whereas carmustine (BCNU) induced ERK- and JNK-dependent cell death of neuronally-differentiated PC12 cells via generation of reactive oxygen species [35]. Here, JUN is linked to central nervous system cancer.