EZH2 and leukemia: Both human leukemia cell lines and zebrafish myeloid malignancies and xenograft models were utilized to study the pharmacological function and mechanisms of Tan I. We found that Tan I can inhibit both normal and malignant hematopoiesis by binding directly to EZH2 and subsequent repression of the histone H3K27 methyltransferase activity of PRC2 complex.