RRM2 and glioblastoma: Even though the extensive exploration of RRM2 in GBM was rare, Li C. et al. illustrated that RRM2 was overexpressed in human GBM cells and can promote proliferation, migration, and invasion but inhibit apoptosis of GBM cells at experiment level [38]; however, the study only focused on RRM2 simply and the signaling pathway about how RRM2 was involved in was not mentioned.