Fig. 6

RSPO2 DNA methylation and gene expression levels are anti-correlated along the adenoma to carcinoma sequence. A Barplot depicting the DNA methylation status of colon organoids obtained from FAP or control patients. Data represent the average methylation value of the four CpG sites identified as differentially methylated in our study. Dashed lines indicate the median DNA methylation value of FAP or control organoids and statistical significance between these groups was calculated by means of a one-sided Welch’s t-test. B Oncoprint representation of the TCGA-COAD samples with mutations in the APC, KRAS and TP53 genes included in these analyses. C Boxplots illustrating the DNA methylation score of the indicated samples along the adenoma to carcinoma sequence in the context of a single (APC), double (APC + KRAS) or triple mutant group (APC + KRAS + TP53). Statistical significance was inferred using a one-sided Wilcoxon rank sum exact test (*p value < 0.05). D Scatter plots showing the correlation between DNA methylation and gene expression levels for the gene RSPO2 in the context of the above-mentioned categories. Resulting Spearman correlations and p values are indicated in the figure legend. E Kaplan–Meier plot showing the overall survival estimates of the single, double- and triple-mutant categories. p value refers to differences in event rates between the Kaplan–Meier curves and was calculated with the log-rank test function