Fig. 1

5hmC levels are increased in liver metastasis tissue compared to primary colon tumours in CRC. A Mass spectrometer analysis for global 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) levels in DNA from 14 normal colon (NC) tissues from CRC patients; 15 tumours in colon (TC) and 10 metastases to liver tumours (LT), showing global demethylation with CRC progression for 5mC. By contrast global 5hmC in metastasis increases compared to the primary cancers. Boxplots depict median and interquartile ranges and standard deviation. ***P < 0.005. Supporting data values are in Additional file 6. B RNA-seq data downloaded [28], showing normalised read counts for TET transcripts in normal colon (NC), tumour colon (TC) and metastasised to liver tumours metastasis (LT). Error bars represent standard deviation around the mean. C Kaplan-Meier plots for time (years) to metastasis generated from the Loboda Yeatman study of colon cancer [29, 30], dividing patients into high or low risk for metastasis depending on TET2/TET3 expression. Concordance index = 57.87, log-rank equal curves P = 0.1093, R^2 = 0.166/0.994. Risk groups hazard ratio = 1.83 (conf. int 0.86–3.86). D TET2 and TET 3 expression in these high and low metastasis risk groups. Patients with high risk of metastasis have higher expression of TET (P = 0.000333); no significant difference for TET3 expression (P = 0.965127)