Objective: To study the clinical features of acute lymphoblastic leukemia (ALL) in children with IKAROS family zinc finger 1 (IKZF1) deletion, and to observe the effect of increasing the intensity of chemotherapy on the prognosis of this disease.
Methods: A total of 278 children diagnosed with ALL between December 2015 and February 2018 were systematically treated according to the Chinese Children's Leukemia Group-ALL 2008 protocol (CCLG-ALL 2008). The patients were divided into an IKZF1-deleted group and a control group according to the presence or absence of IKZF1. The IKZF1-deleted group was treated with the regimen for high-risk group (HR) in the CCLG-ALL 2008 protocol, while the control group received different intensities of chemotherapy according to clinical risk classification. The clinical features and event-free survival rate (EFS) were compared between the two groups.
Results: A total of 24 (8.6%) cases of 278 children were found to have large deletions of exons of the IKZF1 gene. The IKZF1-deleted group had significantly higher proportions of cases with white blood cell count ≥50×109/L at initial diagnosis, BCR-ABL1 fusion gene positive, minimal residual disease ≥10% on the 15th day of induction remission treatment, minimal residual disease-high risk and clinical risk classification-high risk compared with the control group (P<0.05). The 3-year EFS rate (76%±10%) in the IKZF1-deleted group was lower than that in the control group (84%±4%), but with no significant difference between the two groups (P=0.282). The estimated 3-year EFS rate in the IKZF1-deleted-non-HR group (actually treated with the chemotherapy regimen for HR in the CCLG-ALL 2008 protocol) was 82%±12%, which was lower than that in the control-non-HR group (86%±5%), but there was no significant difference (P=0.436).
Conclusions: ALL children with IKZF1 deletion have worse early treatment response, and increasing the intensity of chemotherapy might improve the prognosis.
目的: 总结伴IKZF1基因缺失儿童急性淋巴细胞白血病（ALL）的临床特征并观察提高化疗强度对其预后的影响。
方法: 2015年12月至2018年2月间确诊并按照中国儿童白血病协作组-ALL 2008（CCLG-ALL 2008）方案规范治疗的ALL患儿共278例，根据有无IKZF1基因缺失将其分为IKZF1基因缺失组和IKZF1基因正常组，IKZF1基因缺失组均接受CCLG-ALL 2008高危（HR）方案治疗，IKZF1基因正常组则按临床危险度分型接受不同强度化疗，比较两组的临床特征及无事件生存（EFS）率。
结果: 278例患儿中共24例（8.6%）检出IKZF1基因外显子大片段缺失。IKZF1基因缺失组初诊时WBC ≥ 50×109/L、BCR-ABL1融合基因阳性、诱导缓解治疗第15天微小残留病≥ 10%、微小残留病-HR、临床危险度-HR所占比例均高于IKZF1基因正常组（P < 0.05）。IKZF1基因缺失组3年EFS率（76%±10%）低于IKZF1基因正常组（84%±4%），但差异无统计学意义（P=0.282）；其中，IKZF1基因缺失组-非HR（实际按CCLG-ALL 2008 HR方案化疗）的预计3年EFS率为82%±12%，低于IKZF1基因正常组-非HR（86%±5%），但差异无统计学意义（P=0.436）。
结论: 伴IKZF1基因缺失的儿童ALL早期治疗反应更差，提高化疗强度可能改善其预后。