CHEK1 and cancer: A similar analysis of gene expression data from the 1036 cancer cell lines present in the Cancer Cell Line Encyclopaedia26 revealed similar, though less robust, correlations between CDC6 and CHEK1 mRNA expression levels in colon (R2 = 0.515), CNS (R2 = 0.352), liver (R2 = 0.325), oesophageal (R2 = 0.509), ovarian (R2 = 0.240) and pancreatic (R2 = 0.311) but not breast (R2 = 0.060) or lung (R2 = 0.072) cancer (Supplementary Fig. S7).