ALK-dependent transcription factor networks are associated with epigenomic alterations of DNA methylation in ALCL

Aberrant DNA methylation patterns of malignant cells allow for the study of the tumor phenotype and behavior, and can be used for tumor classification. Here, we describe the genome-wide DNA methylation signatures of a T cell lymphoma that is driven by the oncogenic fusion protein NPM-ALK. Differences in DNA methylation of tumor cells compared to normal T cells concern pathways that are implicated in T cell development and function and reveal a close relationship to thymic progenitor cells. We find DNA hypomethylation in regulatory regions that are enriched for conserved transcription factor binding motifs for NPM-ALK dependent transcription factors, such as AP1. Our results suggest a direct relationship of oncogenic signaling with epigenetic modifications via transcription factor induction and occupancy. Archived fresh frozen tissue from 5 female ALK+ patients and blood samples for CD3 T cell isolation from 5 healthy age matched female patients as controls were used