PROGNOSTIC IMPACT OF WT-1 GENE EXPRESSION IN EGYPTIAN CHILDREN WITH ACUTE LYMPHOBLASTIC LEUKEMIA

Abstract

Background: Acute lymphoblastic leukemia (ALL) is the most common childhood cancer representing 23% of pediatric cancers. Wilms' tumor -1 gene has is a novel prognostic factor, minimal residual disease marker and therapeutic target in acute leukemia. Aim of the work: The aim of this work was to study the impact of WT-1 gene expression in prognosis of Egyptian children with ALL. Patients and methods: This study was conducted on 40 children with newly diagnosed ALL who were subjected to full history taking, thorough clinical examination and laboratory investigations including; complete blood count, LDH, BM aspiration, cytochemistry, immunophenotyping, assessment of WT-1 Gene by real time PCR in BM samples at time of diagnosis. Results: Positive WT-1 gene expression was found in 22 cases (55%) and negative expression in 18 cases (45%). Positive WT-1 gene expression group (n=22) includes 14 males and 8 females with mean age at presentation of 5.261 ± 0.811 while negative WT-1 gene expression group (n=18) includes 12 males and 6 females with mean age at diagnosis of 9.669 ± 3.731 with significantly older age in negative WT-1 gene expression group but no significant differences between positive and negative WT-1 gene expression groups regarding sex and clinical presentations. There were no significant differences in platelets and WBCs counts, hemoglobin and LDH levels and number of peripheral blood and BM blast cells at diagnosis between positive and negative WT-1 gene expression groups but after induction therapy there were significantly lower BM blast cells in positive WT-1 gene expression group. There were no statistically significant differences between positive and negative WT-1 gene expression groups regarding immunophenotyping. There were significantly higher relapse and death rates and lower rates of CR, DFS and OAS in negativeWT-1 gene expression group.MRD at end of induction therapy was found in 14 cases out of 40 patients. There was significantly higher number of cases with MRD in negative WT-1 gene expression group (In 26 cases with negative MRD; 20 have positive WT-1 gene expression and 6 have negative WT-1gene expression while in 14 cases with positive MRD ; 12 cases showed negative WT-1 gene expression and 2 cases showed positive WT-1 gene expression) (p value = 0.006). Conclusions and Recommendation: WT-1 gene expression is important prognostic factor in patients with ALL and therefore we recommend its incorporation into novel risk-adapted therapeutic strategies in patients with ALL.