The effects of purity adjustment on X-chromosome methylation.

A) Density plot highlighting the beta distribution of inferred non-tumor samples (red) and normal breast tissue (blue) in X-chromosome promoters for samples in the TCGA BRCA cohort. Partitioning of promoters based on average methylation state into hypo-, hyper-, and Xi showed high concordance in the respective data sets. Hypomethylated promoters were more frequently found to overlap previously published genes that undergo X-escape. B) Purity-adjustment of tumor sample methylation beta values result in a distribution that more closely adheres to the distribution expected from the process of Lyonization.