EPZ004777 is primarily used in research settings to study the role of histone methyltransferases in gene regulation. It is a selective inhibitor of DOT1L, an enzyme involved in the methylation of histone H3, which plays a critical role in chromatin structure and gene expression. By inhibiting DOT1L, this compound helps researchers investigate its impact on cellular processes, particularly in the context of cancer biology. It has been utilized in studies focusing on leukemia, where aberrant DOT1L activity is linked to disease progression. Additionally, EPZ004777 serves as a tool to explore potential therapeutic strategies targeting epigenetic modifications in various diseases.