Objective.To investigate the differentiation process of the human glioblastoma cells. Methods.Differential display reverse transcribed-PCR（DDRT-PCR） was used to isolate the genes differentially expressed in control and all-trans retinoic acid treated human glioblastoma cell line BT-325.Routine method of cDNA library screening was performed to clone full-length cDNA. Results.Thirty-six RT-PCR reactions were performed and 64 differentially expressed fragments were recovered

amplified and cloned.Of them

46 ESTs were sequenced and delivered into the GenBank.The homology comparison using BLAST algorithm revealed that 22ESTs are highly homologous with the known genes and many of them play important roles in the cell differentiation progress.A dot-blot hybridization was conducted to certify the differentiation expression.The result showed that 27 EST clones are expressed at different level in control and all-trans retinoic acid treated BT-325 cells.A full-length cDNA was cloned using the EST-HGBB098. Conclusion.DDRT-PCR was a simple and effective method to serially analyze the differentially expressed genes.