Objectives: To study the clinical and prognostic significance of the preferentially expressed antigen of melanoma (PRAME) gene in the absence of specific fusion gene expression in children with B-lineage acute lymphoblastic leukemia (B-ALL).
Methods: A total of 167 children newly diagnosed with B-ALL were enrolled, among whom 70 were positive for the PRAME gene and 97 were negative. None of the children were positive for MLL-r, BCR/ABL, E2A/PBX1, or ETV6/RUNX1. The PRAME positive and negative groups were analyzed in terms of clinical features, prognosis, and related prognostic factors.
Results: Compared with the PRAME negative group, the PRAME positive group had a significantly higher proportion of children with the liver extending >6 cm below the costal margin (P<0.05). There was a significant reduction in the PRAME copy number after induction chemotherapy (P<0.05). In the minimal residual disease (MRD) positive group after induction chemotherapy, the PRAME copy number was not correlated with the MRD level (P>0.05). In the MRD negative group, there was also no correlation between them (P>0.05). The PRAME positive group had a significantly higher 4-year event-free survival rate than the PRAME negative group (87.5%±4.6% vs 73.5%±4.6%, P<0.05), while there was no significant difference between the two groups in the 4-year overall survival rate (88.0%±4.4% vs 85.3%±3.8%, P>0.05). The Cox proportional-hazards regression model analysis showed that positive PRAME expression was a protective factor for event-free survival rate in children with B-ALL (P<0.05).
Conclusions: Although the PRAME gene cannot be monitored as MRD, overexpression of PRAME suggests a good prognosis in B-ALL.
目的: 研究在无特异性融合基因表达时，黑色素瘤特异性抗原（preferentially expressed antigen of melanoma，PRAME）基因阳性在儿童急性B淋巴细胞白血病（acute B lymphoblastic leukemia，B-ALL）中的临床及预后意义。方法: 纳入167例新诊断的B-ALL患儿，其中70例PRAME基因阳性，97例PRAME基因阴性，所有患儿均不表达MLL-r、BCR/ABL、E2A/PBX1、ETV6/RUNX1，分析2组患儿的临床特点、预后及预后的相关因素。结果: PRAME阳性组肝肋下>6 cm患儿比例高于PRAME阴性组（P<0.05）。诱导化疗后PRAME基因拷贝数较治疗前下降（P<0.05），诱导化疗后微小残留病（minimal residual disease，MRD）阳性组中，PRAME基因拷贝数与MRD水平无相关性（P>0.05）；在诱导化疗后MRD阴性组中，二者亦无相关性（P>0.05）。PRAME阳性组4年无事件生存率高于PRAME阴性组（87.5%±4.6% vs 73.5%±4.6%，P<0.05），2组4年总生存率差异无统计学意义（88.0%±4.4% vs 85.3%±3.8%，P>0.05）。Cox比例风险回归模型分析显示PRAME基因表达是影响B-ALL患儿4年无事件生存率的保护因素（P<0.05）。结论: 尽管PRAME基因不能作为MRD监测，但在B-ALL中PRAME基因过表达提示预后良好。.
Keywords: Acute lymphoblastic leukemia; Child; Minimal residual disease; Preferentially expressed antigen of melanoma.