Expression of CD117 in Acute Leukemia

Abstract

C-kit is an early. haematopoietic marker which identifies the transmembrane tyrosine kinase receptor encoded by the human c-kit proto- ' oncogene located on chromosome 4q21.

It is expressed in 1 to 4% of normal human bone marrow •

mononuclear cells. A ligand for c-kit has been isolated and named as stem

;.. cell factor. The interaction of the c-kit with its ligand plays a fundamental role in haematopoiesis.

Our aim was to detect expression of c-kit in different types of acute leukemias. The study was carried on 50 patients suffering from acute leukemia, they included 30 patients with AML (group I), 14 patients with ALL (group II), 4 patients with CML in blast crisis (group III) and 2

patients with RAEB in transformation to AML (group IV).

All the patients were subjected to haematological examination including complete blood picture and bone marrow examination for morphologic and immunologic diagnosis. Expression of c-kit was done by APAAP technique.

We found that c-kit was expressed in 60% of group I patients, non of group II, 50% of group III and 100% of group IV patients.

There was a significant statistical correlation between expression .of c-kit and degree of myeloid differentiation by FAB subtypes. On the contrary, there was no significant correlation between CD34 expression and the degree of myeloid differentiation.