AIM:To study the effect of cell fusion on metastatic ability of mouse hepatocarcinoma cells and the factors involved in the process of metastasis.METHODS: By the method of successively increasing the concentrations, cell fusion and limit dilution, 8-Ag resistant cells were selected, and HGPRT-Hca-P cells and eight cloned hybridoma cells were obtained. To observe their metastatic ability, they were inoculated into mice foodtaps and the drainage lymph nodes were examined under microscope.RESULTS:The end concentration of 8-Ag which was used to select HGPRT deficient Hca-P cells was 30mg/L.All the cells selected died in HAT culture medium in one week.Fused cells appeared approximately 9 days later. They were round, transparent and a little larger than their parental cells. Eight clones of hybridoma cells were obtained and named as PSH1-PSH8. The metastatic rate of HGPRT-Hca-P cells and PSH7 cells was 28.6% and 71.4% respectively, the difference being significant (P < 0.05). The metastatic rate of other clones was no more than 20% and there was no significant difference from HGPRT-Hca-P cells (P >0.05).CONCLUSION:In normal mice splenic lymphocytes, there are some factors that could inhibit tumor metastasis, however, there are some other factors accelerating tumor cells to metastasize. The establishment of PSH7 provides an experimental model which could be used to study the factors involved in metastasis.