KRAS and neoplasm: Biomarker analysis of CORRECT trial data demonstrated that benefit from regorafenib was independent of the RAS pathway mutational status of the tumour, suggesting primarily an anti-angiogenic mechanism of action, and that liquid biopsy could be reliably used to characterise clonal mutations.8 We investigated if the circulating tumour genotype could be used as a biomarker of sustained anti-angiogenic activity to regorafenib by tracking known KRAS clonal mutations and performing serial plasma analysis by highly sensitive ddPCR methodology, at clinically relevant time points.