Sample clustering. (a) Hierarchical clustering of seven breast cancer methylation profiles using 1-Pearson's correlation distance. (b) Principal Component Analysis (PCA) of seven breast cancer methylation profiles, plot shows principal component 1 and principal component 2 for each sample. Samples closer to each other in principal component space are similar in their methylation profiles.
Akalin et al. Genome Biology 2012 13:R87 doi:10.1186/gb-2012-13-10-r87