OBJECTIVE: To investigate Daxx expression and its clinical significance in children with acute leukemia. METHODS: The expression of Daxx protein was detected by immunohistochemical assay in 50 children with newly diagnosed acute leukemia (34 cases of acute lymphocytic leukemia and 16 cases of acute non-lymphocytic leukemia). Twenty children with normal bone marrow were used as the control group. RESULTS: Daxx protein was expressed in 38.0% of 50 children with acute leukemia, which was significantly higher than that of the control group (5.0%) (P<0.05). The children with acute non-lymphocytic leukemia had significantly higher Daxx expression levels (62.5%) than those with acute lymphocytic leukemia (26.5%; P<0.05) as well as the control group (P<0.05). There were no significant differences in the Daxx expression between acute lymphocytic leukemia children and the control group. Daxx protein was expressed in 55.6% of high risk group of acute lymphocytic leukemia but it was not expressed in standard risk group of acute lymphocytic leukemia (P<0.05). CONCLUSIONS: Daxx expression is abnormal in children with acute leukemia and associated with some clinical features of acute leukemia, suggesting that it may play an important role in the genesis and development of acute leukemia. ［Chin J Contemp Pediatr, 2007, 9 (1) :33-36］