OBJECTIVETo explore the expression of epidermal growth factor receptor (EGFR) in hematopoietic cells and investigate its relationship to apoptosis in myelodysplastic syndrome (MDS) patients.

METHODMononuclear cells from 18 MDS patients were used to analyze the expression of EGFR and the apoptotic signals by immunocytochemical technique and TdT-mediated dUTP nick end labelling (TUNEL) fluorescein. Flow cytometry (FCM) sorted CD(34)(+) cells from 15 MDS cases and 6 normal donors were also analyzed for the EGFR expression and apoptotic signals. Nine normal marrow samples were taken as controls. EGFR expression and its relationship to apoptosis were analysed.

RESULTS(1) There was a higher EGFR expression rate (38.6 +/- 24.6)% in nucleated cells of MDS marrow than in normal marrow (18.1 +/- 14.0)% (P < 0.05). (2) Apoptosis occurred much more in EGFR negative cells (16.1%) than in EGFR positive cells (1.4%) (P < 0.01). EGFR expression showed negative correlation with apoptosis (r = -0.701; t(r) = 3.60; P < 0.01). (3) In CD(34)(+) cells, EGFR expression rate seemed higher in RAEB/RAEB-t/CMML than that in RA/RAS (20.6 +/- 27.9 vs 8.9 +/- 11.8%) subgroup (P > 0.05), while apoptosis was lower in RAEB/RAEB-t/CMML subgroup than in RA/RAS cases (18.2 +/- 12.5 vs 45.2 +/- 20.5%) (P < 0.05).

CONCLUSIONThere is overexpression of EGFR in MDS cases. And it seems that the overexpressed EGFR represent somewhat the malignant proliferation in MDS and suppress apoptosis through a unknown mechanism.