Abstract: Objective To explore the expression of the CD90 gene at different stages of chemically induced hepatocellular carcino-ma（HCC）in C57BL/6J mice. Methods HCC was chemically induced in an experimental group of 50 male mice，while a control group of 50 male mice was raised normally.Every 4 weeks，some animals were sacrificed to collect specimens.Changes in CD90 expression were detected by RT-PCR，FQ-RT-PCR and Western blot，while pathological changes were assessed using HE staining. Results After 16 weeks of chemical induction，the experimental mice had obvious nodules with diameters of 2~25 mm. Tissue in the experimental group showed pathological changes consistent with well-differentiated HCC，including structural disorder，dysplasia，pathological mito-sis and partial cirrhosis.RT-PCR，FQ-RT-PCR and Western blots showed CD90 expression to be significantly higher in the liver tissue of the experimental mice than in the liver tissue of control mice after 16 weeks of induction（P<0.05）. Conclusion The expression of liver cancer stem cell marker CD90 increases gradually during hepatocarcinogenesis.CD90 plays a regulatory role in the occurrence and development of HCC.

Key words: Liver neoplasms, Stem cell, CD90, Carcinogenesis, Dynamic changes