Metaplastic cell lineages arising in response to chronic injury are precursors for the evolution of dysplasia and adenocarcinoma. Although a subtype of intestinal metaplasia has been associated with gastric adenocarcinoma, the link between this lineage and the evolution of gastric adenocarcinoma has remained unclear. Wang et al (1998) have reported that an aberrant metaplastic cell lineage with morphological characteristics similar to Brunner's glands of the duodenum develops in the fundic mucosa of mice infected with Helicobacter felis. This metaplastic lineage expresses the trefoil peptide spasmolytic polypeptide (SP). Given the epidemiological association of Helicobacter species infection with gastric cancer, we hypothesized that this SP-expressing metaplastic (SPEM) lineage may represent a precursor to or appear commensurate with gastric adenocarcinoma. The SPEM lineage was present in 68% of fundic biopsies from patients with fundic Helicobacterpylori-associated gastritis, but was absent in biopsies of fundic mucosa from patients without H. pylori infection. In a review of archival samples from 22 resected gastric adenocarcinomas, we found the SPEM lineage in 91% of cases, typically located in mucosa adjacent to the carcinoma or areas of dysplasia. Importantly, 59% of resections showed SP immunoreactivity within dysplastic cells. These data indicate a strong association of the SPEM lineage with both chronic H. pylori infection and gastric adenocarcinoma.