CLOCK and breast cancer: In the context of this work, what makes the RAC1 pathway an interesting target from a chronopharmacological perspective, is that it is related to most of the pathways linking GBM to the circadian clock: (a) an NR1D2 knock-down was found to impair p-Rac1, (b) the p38 MAPK pathway is known to be activated by RAC1 and (c) CK-1e mutants were shown in breast cancer to activate the non-canonical Wnt/Rac-1/JNK pathway contributing to cancer development [47].