Detection of c-KIT antigen (CD117) and c-kit mRNA in acute leukemia

Study population: 29 patients (pts), mean age 50 years (range 18-78), with acute leukemia ( 8 ALL. 21 AML) were studied at diagnosis. Methods:detection of GDI 17 on bone marrow and/or peripheral blood samples was carried out by flow cytometric analysis using a 95C3 monoclonal antibody; positivity was defined as > 20% of stained leukemic cells, c-kit mRNA analysis was performed by RT-PCR using 8 differenl primers spanning the coding region of the gene and by dot blot analysis using a specific probe. Results : 17/21 AML pts resulted CD 117 positive ; in this group a relevant amount of c-kit mRNA was detected in all the cases. The table summarizes the results in the group of CD! 17 negative pts (7 B-ALL, 1 T-ALL, 4AML) N Dagnosis CD34 CD117 c-kil c-kit Karyoiype bcr/abl % % RT-PCR dot blot transcript 1 B- ALL 91 1 pos +++ complex kiryorype ND 2 B LL 96 004 pos + 46XX p210 3 B- LL* 75 3 pos ++ 46XX 1(9 22) pl90 4 B- LL* 88 03 pos ++ 47XX-21 ND 5 B- LL* 9? 03 pos 46XX t(9 22] p210 6 B- LL* 91 02 pos ++ ND p190 7 B-ALL* 57 15 pos + ND ND 8 T ALL 4 01 pos ++ ND p210 9 AML 78 g pos 46XY-21 mar 10 AML 01 03 pos ++ ND 11 AML 30 0.2 pos + 46XY 1(5 17) - 12 AML 2 6 pos 46XX - Myeloid antigen positive;ND: not determined; Complex karyotype: more than 2 abnormalities Comment: in agreement with other reports we did not find CD117 expression on B-ALL blasts ; dot blot analysis showed consistent levels (+++) of c-kit mRNA in 7/12 CDU 7 negative pts and trace levels (+) in the remaining ones.