Hlady et al. (2012) deliberately inactivated DNMT3B in T-cells in a mouse model of MYC-induced lymph angiogenesis, leading to increased cell proliferation and accelerated lymphoma development. In the study process, they found that numerous gene promoter was not methylated in DNMT3B−/- pretumor thymocytes, which implicated that DNMT3B maintained cytosine methylation in cancer. The gene discussed is DNMT3B; the disease is cancer.