Objective: To determine the expression and function of the c-kit receptor in bone marrow mononuclear cells (BMMNC) of patients with myelodysplastic syndromes (MDS).
Methods: Direct immunofluorescence assay and reverse transcriptase-polymerase chain reaction (RT-PCR) were used to detect c-kit protein and c-kit mRNA expressions in the BMMNC of 29 MDS patients and 10 normal controls. Cell culture was used to detect the function of the c-kit receptor.
Results: c-kit protein expression in the MDS group was significantly higher than that in the control group (8.58% +/- 5.28% vs 3.04% +/- 1.49%, P < 0.05). c-kit protein expression in the refractory anemia (RA) group was significantly lower than that in the RA with an excess of blasts (RAEB)/RAEB in transformation (RAEB-t) group (5.12% +/- 2.13% vs 10.01% +/- 5.07%, P < 0.05). The rate of c-kit protein expression was 32.43% in acute myeloblastic leukemia (AML) cases transformed from MDS (t-AML). c-kit mRNA expression in the MDS group was correlated with c-kit protein expression. Interleukin-3 (IL-3) and erythropoietin (Epo), with or without stem cell factor (SCF), upregulated c-kit protein and its mRNA expression. In the presence of IL-3 and Epo, SCF showed significant stimulating effects on the formation of CFU-GM and BFU-E in semi-solid cultures of normal BMMNC, but had no effects on those of the MDS patients.
Conclusion: The protein and mRNA expression of the c-kit receptor in the BMMNC of MDS patients were higher than those of normal controls, and the function of this receptor in MDS BMMNC was abnormal.