目的：分析具有不同融合基因的B系急性淋巴细胞白血病（acute lymphoblastic leukemia, ALL）患儿的临床特征、分子遗传学特征与免疫分型和预后之间的差异。方法：总结2006年3月至2008年12月北京大学人民医院儿科收治的B系ALL患儿80例，其中TEL/AML1阳性组18例、E2A/PBX1阳性组14例、BCR/ABL阳性组11例、MLL/AF4阳性组2例及4种融合基因均阴性的患儿35例，总结其临床特征、形态学、免疫分型及分子生物学、染色体等相关资料，并分析各组患儿的无病生存率（DFS），随访时间至2009年4月。结果：TEL/AML1阳性组中，年龄≤5岁的患儿占66.7%，发病时的肿瘤负荷不高，形态学以FAB-L2型多见，而染色体核型均未见t(12;21)的异常，长期预后好，至今有17例患儿达到无病生存；14例 E2A/PBX1阳性组中，女性患儿多见，其中13例患儿形态学表现为FAB-L1型，12例患儿的免疫分型为前B细胞型，DFS接近80%；11例BCR/ABL阳性患儿中10例免疫分型为普通B细胞型，FAB-L1 和L2 型各4例。DFS不足20%；而MLL/AF4阳性的2例患儿发病时肿瘤负荷均高，形态学均为FAB-L1型，免疫分型均为早前B细胞型。1例化疗早期放弃治疗，另1例至今已无病生存达21个月。结论：具有不同融合基因的患儿，其临床特征、免疫分型及预后等方面具有显著差异。［中国当代儿科杂志，2010，12（3）：172-176］

OBJECTIVE: To investigate whether there were differences in the clinical characteristics, cytogenetic characteristics, immunophenotype and prognosis in children with B cell type acute lymphoblastic leukemia (B-ALL) carrying different fusion genes. METHODS: The research included 80 children with B-ALL from Peking University People’s Hospital between March 2006 and December 2008. Eighteen children were positive for TEL/AML1, 14 for E2A/PBX1, 11 for BCR/ABL,and 2 cases for MLL/AF4, and 35 cases were negative for all of the 4 fusion genes. Data including clinical characteristics, morphology, immunophenotype and cytogenetic characteristics were collected, and the disease-free survival (DFS) was evaluated. The children were followed up until April 2009. RESULTS: In the 18 children with TEL/AML1+B-ALL, 66.7% were younger than 5 years old. They had low tumor load. FAB-L2 morphology was commonly observed, but t(12;21) was often absence in these children. Up to now，17 children who survived were disease-free. In the 14 children with E2A/PBX1+B-ALL, the majority were female. Thirteen children showed FAB-L1 morphology. Twelve children showed pre-B-ALL immunophenotype. The EFS was close to 80%. In the 11 children with BCR/ABL+B-ALL, 10 children showed common B type immunophenotype. FAB-L1 and FAB-L2 morphology was found in 4 children respectively. The DFS was less than 20%. Two children with MLL/AF4 positive B-ALL had high tumor load. Their morphologic diagnosis was FAB-L1. Both showed the Pro-B-ALL immunophenotype. One child discontinued treatment at the early stage of chemotherapy, and the other child survived disease-free until now. CONCLUSIONS: The B-ALL children with different fusion genes have different clinical characteristics, immunophenotypes and prognosis.［Chin J Contemp Pediatr, 2010, 12 (3):172-176］