Clinical features and prognosis of B-cell acute lymphoblastic leukemia children with intrachromosomal amplification of chromosome 21 / 白血病·淋巴瘤

ABSTRACT

Objective:To investigate the clinical features and prognosis of B-cell acute lymphoblastic leukemia (B-ALL) children with intrachromosomal amplification of chromosome 21 (iAMP21).Methods:The data of 233 children diagnosed with B-ALL who received chemotherapy according to Chinese Children Cancer Group (CCCG) - acute lymphoblastic leukemia -2015 (CCCG-ALL-2015) protocol in the Affiliated Union Hospital of Fujian Medical University from January 2019 to December 2020 were retrospectively analyzed. These patients were divided into iAMP21 group and non-iAMP21 group according to whether iAMP21 was positive in the bone marrow fluid of children before chemotherapy based on ETV6-RUNX1 probe fluorescence in situ hybridization. Children in iAMP21 group received CCCG-ALL-2015 intermediate-risk group regimen induction chemotherapy, while children in non-iAMP21 group received different intensities of chemotherapy according to the clinical risk classification. The clinicopathological characteristics of patients were compared in both groups, the therapeutic efficacy and prognosis of B-ALL children with iAMP21 was analyzed.Results:iAMP21 was found in 5 (2.1%) of 233 B-ALL children. The median hemoglobin concentration in iAMP21 group was higher than that in non-iAMP21 group [99 g/L (71-148 g/L) vs. 74 g/L (30-156 g/L); U = 268.50, P = 0.043]; there were 4 cases (80%) with bone pain in iAMP21 group (5 cases) and 53 cases (23.2%) with bone pain in non-iAMP21 group (228 cases),and the difference in the osteoarticular pain incidence of both groups was statistically significant ( χ2 = 8.53, P = 0.017). There were no significant differences in the proportion of patients with different gender, age, white blood cell counts, platelet counts, hepatosplenomegaly between the two groups (all P > 0.05). Among 5 children with iAMP21, 1 patient was detected with high CRLF2 expression and 1 patient with IKZF1 1-8 exon loss of heterozygosity. The above mentioned two children with iAMP21, whose minimal residual disease (MRD) were still positive after consolidation therapy, and then they received chimeric antigen receptor T-cell treatment and hematopoietic stem cell transplantation. MRD of the other 3 children with iAMP21 turned negative after induction therapy. Up to the last follow-up in October 2021, 5 patients with iAMP21 had disease-free survival. Conclusions:The incidence of B-ALL children with iAMP21 is about 2%. These patients are prone to osteoarticular pain and have relatively mild anemia. The curative effect of some children is still poor after active treatment,which needs to be further clarified with more samples.