Residuals plot of multivariate linear regression model to predict LINE-1 methylation in 869 colorectal cancers. Each dot represents each case. The x axis represents LINE-1 methylation level predicted by the regression model, and the y axis represents the residuals (observed LINE-1 methylation level minus predicted LINE-1 methylation level by the regression model). A distribution of the residuals is approximately normal across predicted LINE-1 methylation levels, except for the presence of outliers (arrow). The arrow suggests the presence of a distinct group of tumors, separate from the normal and homoscedastic distribution around the 0 residual line.