We have applied an analytic strategy to decipher the DNA methylome of 86 mantle cell lymphomas (MCL) in light of the methylome of the entire B-cell lineage. In this way, we first identified two MCL subgroups that respectively carry epigenetic imprints of pre- and post-germinal center B cells. Secondly, we observed that pure tumor-specific changes are rare, as most (89-99%) DNA methylation alterations in MCL are within or in close proximity of those regions showing dynamic methylation in normal B cells. Several thousand of these differentially methylated regions in MCL show concurrent changes in enhancer-associated histone modifications, including a region located 650 Kb away from the MCL oncogene SOX11. At the clinical level, epigenetic and genetic changes co-evolve during MCL progression and the magnitude of epigenetic changes is associated with overall survival of the patients.