Fms-Like Tyrosine Kinase 3 expression in Childhood Acute lymphoblastic Leukemia at South Egypt Cancer Institute, Assiut University, Egypt

Background: FMS-Like Tyrosine kinase 3 (FLT3) plays an important role in early stages of hematopoiesis. FLT3 stimulation enhances proliferation and reduces apoptosis. One potential mechanism of FLT3 involvement in leukemia is over expression of its wild type and its ligand. The FLT3 protein is highly expressed in most patients with AML. In patients with ALL, FLT3 protein is highly expressed in up to 50% of leukemic blasts. Here, we aimed to evaluate the frequency of FLT3 protein expression in pediatric patients with ALL at South Egypt Cancer Institute, Assiut University, Egypt.
Method: FLT3 surface protein expression on leukemic blasts was detected by flowcytometry of 101 denovo pediatric acute lymphoblastic leukemia patients. High FLT3 expression considered when ≥20% of malignant cells expressed CD135 and low FLT3 expression considered when <20% of malignant cells expressed CD135. Relation between FLT3 expression and other clinical and laboratory findings were studies.
Results: High FLT3 expression was found in 47.5% of patients {39/74(52.7%) of precursor B-ALL and 9/27(33.3%) of precursor T-ALL}. High FLT3 level was significantly expressed in patients with the low risk age group (p < 0.001), patients who had no mediastinal mass, patients without lymphomatous features at presentation and patients with no CNS involvement at presentation (p < 0.001). 75% of patients with high FLT3 expression had TLC <50.000×109 (p=0.004).
Conclusion: High  FLT3  protein  expression  may  be  more  commonly  associated  to  favorable  criteria  of  our  ALL patients.