In these tumour xenograft samples, a correlation was observed between Chk1 S296 phosphorylation and Cdc6 (R2 = 0.815) and a weaker correlation between total Chk1 protein and Cdc6 (R2 = 0.556) but not between pChk1 (S317) and Cdc6 (R2 = 0.004) (Fig. 5b). This evidence concerns the gene CDC6 and neoplasm.