目的：通过单中心小样本研究，探讨我国北方地区儿童急性白血病群体生物学特征。方法：对2003年10月至2006年6月于中国医学科学院血液病医院就诊的688例急性白血病患儿发病情况进行回顾性分析。结果：400例急性淋巴细胞白血病(ALL)患儿的发病高峰为1~4岁，其中B-ALL 218例，T-ALL 34例。154例ALL患儿中高超二倍体占13.0%，低超二倍体占3.9%,假二倍体占5.2%，亚二倍体占5.8%，E2A-PBX1阳性B-ALL占3.9%。222例急性髓系白血病（AML）患儿的发病高峰年龄为10~15岁，以AML-M2最多见。急性杂合性白血病（AHL）占4.2%，中位年龄9岁，74% AHL的患儿在髓系积分中主要以CD13、CD33阳性为主。结论：我国北方地区儿童急性白血病的生物学特性与其他地区及种族之间存在差异，提示在不同环境因素作用下的急性白血病的发生可能存在差别。［中国当代儿科杂志，2009，11（10）：793-796］

OBJECTIVE: To investigate the biologic features of childhood acute leukemia in the northern region of China through a small cohort study in a single center. METHODS: The medical records of 688 children with acute leukemia (age ≤15 years) who were initially diagnosed at Blood Disease Hospital of Chinese Academy of Medical Sciences from October 2003 to June 2006 were retrospectively studied. RESULTS: Four hundred children were diagnosed as acute lymphoblastic leukemia (ALL), with a peak incidence at ages of 1-4 years. Two hundred and eighteen children were classified into B-cell ALL, and 34 into T-cell ALL. In the 154 patients with cytogenetic data, high hyperdiploidy was presented in 13.0% of patients, low hyperdiploidy in 3.9%, pseudodiploidy in 5.2%, and hypodiploidy in 5.8%. E2A-PBX1 fusion gene was expressed in 3.9% of children with B-cell ALL. Two hundred and twenty-two children were diagnosed as acute myeloid leukemia (AML), with a peak incidence at ages of 10-15 years. AML-M2 was the most common subtype. Acute hybrid leukemia (AHL) was confirmed in 24 children (4.2%), with a median age of 9 years. Seventy-four percent of the children with (AHL) had mainly CD13 and CD33 expression in myeloid antigen integral. CONCLUSIONS: There are differences in the biologic features of childhood acute leukemia between the northern region of China and other regions and races, which suggests that there might be differences in the pathogenesis of childhood acute leukemia in different environmental exposures.［Chin J Contemp Pediatr, 2009, 11 (10):793-796］