By comparing gastric ulcer and nonulcer tissues within the same individual, this study is highly original in revealing how MMP-3, -7, and -9 and TIMP-1 expressions are upregulated in gastric ulcers induced by H. pylori infection and NSAID use, respectively (P < 0.05; Table 2, Figures 2 and 3). This evidence concerns the gene TIMP1 and gastric ulcer.