EPZ004777 hydrochloride is primarily used in biochemical research to study and inhibit the activity of DOT1L, a histone methyltransferase enzyme. This compound is particularly valuable in cancer research, as DOT1L plays a role in the regulation of gene expression and is implicated in certain types of leukemia, such as MLL-rearranged leukemia. By inhibiting DOT1L, EPZ004777 hydrochloride helps researchers understand the mechanisms of gene regulation and evaluate its potential as a therapeutic target. Additionally, it is utilized in epigenetic studies to explore the impact of histone methylation on cellular processes and disease development. Its application extends to drug discovery efforts aimed at developing targeted therapies for cancers driven by DOT1L dysregulation.