PLK1 and cancer: By virtue of their ability to induce cell cycle arrest in G2/M by targeting PLK1 (ref. 19), and to dampen the DNA repair response through the inhibition of CHK2 activity, allosteric RAF inhibitors such as KG5 would be expected to have a broad application for the sensitization of genetically diverse tumours to the effects of cancer therapies such as ionizing radiation or etoposide that function by inducing genotoxic stress.