Relation between FLT3 Mutations, High Flow Cytometric FLT3 Expression and CXCR4 Expression in CD34+ Cells in Adult Acute Myeloid Leukemia.

Objective

1. To evaluate the prevalence of FLT3 mutation-interna tanden duplication in adult acute leukemia patients and its clinical significance

2. To evaluate the surface expression of FLT3 difference between AML and non malignant hemopoietic disease, and the possibility of detection of CD135 being included in the diagnostic immunophenotyping of acute leukaemias

3. To study if constitutive FLT3 activity induce cell surface expression of CXCR4 in CD34 cells .

Methods

1. Genomic DNAs from 95 cases of AML and 22 cases of ALL were screened bypolymerase chain reaction and gel electrophoresis for FLT3-ITD mutations.

2. Flow cytometry is used to investigate FLT3 expression in 68 cases AML and 8cases non-malignant hemopoietic disease

3. To investigate FLT3 expression using flow cytometry between 56 cases FLT3-ITD- AML and 12 cases FLT3-ITD+ AML.

Results

1. FLT3-ITD were found in 15 (16%) of 95 AL patients,including 3/ 15 of M1, 4/ 24 of M2, 2/ 18 of M3, 5/ 29 of M5, 1/4 of M6.Significantly more FLT3 mututations were found in AML M1, M5. No FLT3-ITD was found in 22 ALL. FLT3-ITD was associated with a higher peripheral white cell count (P<0.05) and a lower complete remission rate (P<0.05).and was more prevalent in patients with normal karyotype(P<0.05) an t(15;17).

2. High level expression of CD135 in acute myeloid leukaemias has been demonstrated by flow cytometry .Dection of CD135 maybe included in the diagnostic immunophenotyping of AML.

3. Significant difference of FLT3 expression between FLT3 ITD posive cases and FLT3 ITD negative cases.