Objective      To select and identify the specific cell marker of healthy human nucleus pulposus cells.       Methods      Samples were taken from 13 patients who underwent spine fracture internal fixation in Xinqiao Hospital during Apr. 2012 to Dec. 2013. For each patient

healthy nucleus pulposus and cartilage endplate were collected. Total RNA extraction and reverse transcription were performed after monolayer culture of nucleus pulposus cells and chondrocytes from 10 patients separately and the differentially expressed genes were analyzed with microarray gene chip. The same samples were subjected to real-time PCR to evaluate the expression difference on the transcription level. Western blotting was performed to identify the genes with the greatest expression difference on the protein level in the samples from other 3 patients.       Results      Fifteen genes with greater than 20 fold change were found with microarray gene chip. POTEB was proven by real-time PCR results to be the gene with the greatest expression difference. It was identified with Western blot analysis that POTEB expressionlevel was much higher in the nucleus pulposus cell than in the chondrocyte.       Conclusion      POTEB is considered a specific marker for nucleus pulposus cell.