PRIOR CONCURRENT THERAPY: Biologic therapy: At least 2 months since prior growth factors or biological response modifiers for myelodysplastic syndrome except for supportive care No other concurrent hematopoietic growth factors Chemotherapy: At least 2 months since other prior chemotherapy for myelodysplastic syndrome Endocrine therapy: No concurrent glucocorticoids No concurrent androgens Radiotherapy: Not specified Surgery: Not specified Other: No concurrent vitamin A or D derivatives