However, rather surprisingly, of the ‘top 14’ most frequently reported genes that are hypermethylated in human cancers (Cheung et al, 2009), all of which were included in our array analysis, only RASSF1A, APC and ESR1 were methylated in the majority of YSTs and almost none were methylated in germinomas. This evidence concerns the gene ESR1 and germinoma.