This bi-modal effect has been reported in breast cancer cells where partial inhibition of PLK4 dimeric complexes was shown to impair degradation of PLK4, resulting in a paradoxical increase of overall PLK4 activity, consistent with prior reports; we observed centrosome loss indicating complete inhibition beginning at 50 nM of CFI (Fig. 1e)25,28,53. Here, CFI is linked to breast carcinoma.