Promoter methylation and gene expression.

<p>The ratio of gene expression data of tumor to non-cancerous (normal) from a genome-wide gene expression microarray <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0037928#pone.0037928-Martin1" target="_blank">[23]</a> was correlated with the methylation difference between the tissue pairs. The log 2 ratio of gene expression in matched pair tumor and normal is shown on Y axis. The relative methylation frequency is shown on the X-axis. <i>P</i> value and the correlation index; <i>r</i> (Rho) values are from Spearman rank correlation analysis.