DNMT1 and anaplastic large cell lymphoma: This combination caused a significant downregulation of the DNA methyltransferase 1 gene (DNMT1; Figure 5A,D), which correlated with an increase in histone H3 methylation on lysine 4 (H3K4me, a marker of active transcription; Figure 5G) and higher expression of the transcription factor GATA3, which is epigenetically silenced in ALK+ ALCL compared to normal T cells [17].