The expression level of 67-KD LN-R mRNA was observed in high-metastatic PG tumor cells and low-metastatic PAa tumor cells based on the cDNA fragments of 67-KD LN-R amplified by PCR technique and the specific cDNA probe prepared by random primer labeling method. Results showed that the transcripts were homologous in size, about 1.7kb, in PG and PAa tumor cells. The 67-KD LN-R mRNA level was higher in PG than that in PAa tumor cells, and gene amplification was also more marked in PG tumor cells. After treated with 67-KD LN-R monoclonioal antibody (50, 100 and 400 micrograms/ml) for 48 hours, LN-R mRNA of PG tumor cells decreased significantly. It is suggested that 67-KD LN-R may play important roles in metastatic processes of PG tumor cells.