Objective    To establish the subclones of MDA-MB-435s human breast cancer cells with high and low potentiality of metastasis

and then investigate the differences of the expressions of matrix metalloprotainese-2 and -9 (MMP-2 and MMP-9) between these 2 subclones.     Methods    Transwell invasion assay was used to screen the subclones of MDA-MB-435s cells with high- and low- metastatic potentiality. The expressions of MMP-2 and MMP-9 were examined with immunohistochemical staining and Western blot analysis

and cell invasion ability was evaluated Transwell invasion assay.     Results    Transwell invasion assay showed the ivasion ability of breast cancer cells was higher in the cells with high-metastatic potentiality than those with low-metastatic potentiality

with significant difference (P0.05). Immunohistochemistry showed that the expression levels of MMP-2 and MMP-9 were significantly higher in cells with high metastatic potentiality (0.24±0.04 and 0.23±0.05 respectively) than that in cells with low metastatic potentiality (0.16±0.02 and 0.13±0.03 respectively

P0.05). These results were confirmed by Western blot assay. A positive correlation was found between the expression levels of MMP-2/9 and the invasion potentiality of MDA-MB-435s (r=0.957

0.964

P0.05).     Conclusion    The subclones of human breast cancer cells with high- and low- metastatic potentiality can be screen with Transwell invasion assay. Tumour cells to penetrate a matrigel barrier in vitro is closely related with the expression levels of MMP-2 and MMP-9 in human breast cancer cells.