Objective：To investigate the expression of BMI-1 mRNA and MMP-9 mRNA in colon carcinoma cells and its significance.
Methods：The expression of BMI-1 mRNA and MMP-9 mRNA in colon carcinoma cells and human colon smooth muscle cell (CSMC) was detected by RT-PCR technique, and their correlation was analyzed.
Results：The expression of BMI-1 mRNA and MMP-9 mRNA in colon carcinoma cell lines SW620 and LoVo was significantly higher(P＜0.05) than those in colon carcinoma cell line SW480 and CSMC. There was significant positive correlation between the expression of BMI-1 mRNA and MMP-9 mRNA(r=0.966，P＜0.05).
Conclusions：As an oncogene, BMI-1 may act as a biological indicator of invasion capablity of colon carcinoma cells.