Objective To explore the expression of matrix metalloproteinase-11 (MMP-11) gene in gastric cancer and its correlation with transcription factor Sp1.Methods The expressions of the MMP-11 and Sp1 in level of RNA and protein in 11 specimens from the gastric cancer patients s were detected by RT-PCR,differential PCR and Western-blot,respectively.Results Electrophoresis illustration showed MMP-11 mRNA expression had significant differences in eight pairs of gastric cancer tissues and normal tissues,including 7 pairs of over expressed in gastric cancer tissues and low or no expression in normal tissues,and 1 pair of low expression in cancer tissues but high in normal tissues.The relative molecular weight of Sp1 protein was mainly 95×103 in cancer tissue and 106×103 in normal tissues.Activated MMP-11 protein mainly was over expressed in gastric cancer tissues,and low or no expression in normal tissues,but degradable MMP-1 1 protein was not observed.The enzyme prototype of and activated type of MMP-11 protein were also associated with Sp1 protein.Conclusions The MMP-11 mRNA expression in gastric tissue is higher than that in the adjacent tissues.Sp1 protein and MMP-11 protein are expressed in gastric cancer,but are low or no expression in normal tissue.There is relationship between Spl and MMP-11.