中文摘要：

目的初步了解PAX5缺失在无特殊重现染色体异常的B系急性淋巴细胞白血病（B-ALL）患儿中的发生情况,并进一步分析PAX5基因缺失与ALL预后的相关性。方法用多重连接探针扩增（MLPA）技术检测2008年4月至2013年4月初诊无特殊重现染色体异常的B-ALL患儿及对照组（同期非血液系统疾病及肿瘤儿童）的PAX5基因拷贝数情况。根据有无PAX5基因缺失分为缺失组和非缺失组。结果 86例患儿中18例（21%）发生了PAX5缺失。缺失组初诊时白细胞总数明显高于非缺失组（P=0.001）。Kaplan-Meier法分析显示：缺失组无病生存（DFS）率明显低于非缺失组（0.69±0.12 vs 0.90±0.04,P=0.017）,但两组患儿的总生存（OS）率差异无统计学意义（P=0.128）。Cox法分析显示,PAX5缺失为影响DFS的不利因素（P=0.03）。结论 PAX5缺失为无特殊重现染色体异常B-ALL患儿DFS的独立危险因素。

英文摘要：

Objective To identify the incidence of PAX5 deletion in childhood B-lineage acute lymphoblastic leukemia（B-ALL） without reproducible chromosomal abnormalities and to investigate the association between PAX5 abnormalities and prognosis of ALL. Methods Multiplex ligation-dependent probe amplification was used to determine the copy numbers of PAX5 gene in children newly diagnosed with B-ALL without reproducible chromosomal abnormalities between April 2008 and April 2013 and controls（children with non-hematologic diseases or tumors）. The patients were classifiied into deletion group and non-deletion group based on the presence of PAX5 deletion. Results Eighteen（21%） out of 86 children with B-ALL had PAX5 deletion. The deletion group had a significantly higher total white blood cell count at diagnosis than the non-deletion group（P=0.001）. The Kaplan-Meier analysis demonstrated that the deletion group had a significantly lower disease-free survival（DFS） rate than the non-deletion group（0.69±0.12 vs 0.90±0.04; P=0.017）, but there was no significant difference in the overall survival rate between the two groups（P=0.128）. The Cox analysis showed that PAX5 deletion was a risk factor for DFS（P=0.03）. Conclusions PAX5 deletion is an independent risk factor for DFS in B-ALL children without reproducible chromosomal abnormalities.