Fig. 2From: Machine-learned analysis of global and glial/opioid intersection–related DNA methylation in patients with persistent pain after breast cancer surgeryExplorative analysis of the correlations between the methylation status at d = 14 CpG sites in OPRM1, TLR4, or LINE1 and with the pain ratings acquired between 1 and 36 months after breast cancer surgery. At the lower left part, the correlations are shown as ellipses. The narrower the ellipse is drawn, the higher is the correlation coefficient. Positive correlations are indicated by ellipses directed from the lower left corner to the upper right corner of each cell. Negative correlations are indicated by ellipses drawn in the opposite direction from the upper left to the lower right corner of each cell. Ellipses are colored according to the color code of Spearman’s ρ [45] shown at the bottom of the panels. At the upper right parts, the correlations are provided numerically as values of Spearman’s ρ (colored). The corresponding p values are shown in black numbers below the correlation coefficients; “0” indicates p < 1 × 10−5. The figure has been created using the R software package (version 3.4.4 for Linux; http://CRAN.R-project.org/ [40]) and the library “corrplot” (https://cran.r-project.org/package=corrplot [63])Back to article page