Absolute values for global DNA methylation estimated by 4 different methods.

§Data for measurements on DNA from colon biopsies are presented as mean % methylation for 10 paired samples of normal and tumor tissue (± standard error of the mean (SEM)). Data from analysis of DNA from the cells lines represent means of 3 technical replicates (± SEM). NB: The nature of the measurements is different for each of the assays so direct comparison of the methylation percentages between assays cannot be made. *P<0.03 and **P≤0.009; non-parametric Wilcoxon matched-pair test was used for comparison of normal vs. tumor tissue for colon biopsies, and unpaired homoscedastic t-test was used to test for significance between 5-AzaC- treated and untreated cells (each cell line analyzed separately).