OBJECTIVETo investigate the biologic features of childhood acute leukemia in the northern region of China through a small cohort study in a single center.

METHODSThe medical records of 688 children with acute leukemia (age< or =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.

RESULTSFour 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.

CONCLUSIONSThere 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.