List of the 254 genes of Helicobacter pylori strain 26695 used for gene amplification and preparation of the home-made macroarray membranes. Distribution of each gene in the 120 French isolates of this study associated with gastritis (G), duodenal ulcer (DU), gastric MALT lymphoma (MALT) or metaplasia (META). The percentages were based on the binary analysis (presence/absence/) according to the normalization process and the cutoff ratio described in Material ad Methods. "HPXXXX+", genes were designated as ubiquitous genes based on previous comparative analysis [25]; "HPXXXX" are the non-ubiquitous genes; the 48 most discriminatory genes identified as key combinations of variables (genes/axes) from the Principal Component Analysis, which were used for the clustering analysis, are in bold (Figure 2).