Unsupervised hierarchical clustering of CpG methylation in GCTs by tumor histology. Heat map from unsupervised hierarchical clustering based on Manhattan distance and average linkage of the 1404 autosomal CpG loci that passed initial quality control checks. Colored bars represent histologic subtype of the tumor. Light purple represents mature teratoma, dark purple represents immature teratoma, orange represents germinoma and red represents yolk sac tumor. Samples are in columns (N = 51) and CpG loci are in rows. Blue indicates high level of methylation (51-100%), black equals 50% methylation, and yellow indicates low level of methylation (0-49%).